
Land -based activities
and their physical impacts
on marine habitats
of the Gulf of Maine
Final draft of a working paper prepared for the Global
Programme of Action Coalition for the
Gulf of Maine (GPAC) and the Secretariat
of the Commission for Environmental Cooperation
This working paper was prepared by:
J.A. Percy
Clean Annapolis River Project
P.O. Box 395, Annapolis Royal
Nova Scotia, B0S 1A0, Canada
Commission for Environmental Cooperation
Montreal, Canada
May 1997
This working paper was prepared for the Global Programme of Action Coalition for the Gulf of Maine (GPAC) and the Secretariat of the Commission for Environmental Cooperation (CEC). The views contained herein do not necessarily reflect the views of the CEC, or the governments of Canada, Mexico or the United States of America.
Reproduction of this document in whole or in part and in any form for educational or non-profit purposes may be made without special permission from the CEC Secretariat, provided acknowledgment of the source is made. The CEC would appreciate receiving a copy of any publication or material that uses this document as a source.
© Commission for Environmental Cooperation, 1997
For more information about this or other publications from the CEC, contact:
Commission for Environmental Cooperation
393, rue St-Jacques Ouest, bureau 200
Montréal (Québec) Canada H2Y 1N9
Tel: (514) 350-4300 Fax: (514) 350-4314
http://www.cec.org
TABLE OF CONTENTS
Profile of the Commission for Environmental Cooperation
Global Programme of Action Coalition for the Gulf of Maine
1. Introduction
2. Background on the GPA/CEC
3. Approach and sources of information
4. Overview: land-based activities in watershed/coastal zone
4.1 Population growth and urbanization
4.2 Alterations to coastal morphology
4.3 Hydrologic alterations/tidal restrictions
4.4 Resource harvesting
4.5 Energy production
4.6 Recreation and tourism
4.7. Confounding factors and intermediary processes
5. Marine habitats
5.1 Estuaries
5.2 Salt marshes
5.3 Mud flats
5.4 Sand beaches
5.5 cobble/shingle beaches
5.6 Rockweed beds
5.7 Coastal islands
5.8 Inshore benthic
5.9 Inshore pelagic
5.10 Eelgrass meadows
5.11 Kelp beds
5.12 Offshore benthic
5.13 Offshore pelagic
6. Ranking the habitat/activity issues
7. Management objectives for priority issues
8. Bibliography
9. Acknowledgments
Appendix 1.
LIST OF TABLES AND FIGURES
Table 1.
Matrix of potential impacts of land-based activitieson Gulf of Maine marine habitats 76
Table 2. Relative significance of impacts of land-based activities
on marine habitats based on selected attributes 77
Figure 1. Productivity of selected coastal habitats. Black portion
of bar indicates upper and lower values of range of available estimates 79
Figure 2. Frequency distributions (percent) of marine habitat concerns based
on interviews with community groups and CLF/CCNB compilations 80
Figure 3. Frequency distributions (percent) of land-based activity concerns based on interviews with community groups and CLF/CCNB compilations 81
Profile of the Commission for Environmental Cooperation
In North America, we share vital natural resources including air, oceans and rivers, mountains and forests. Together, these natural resources are the basis of a rich network of ecosystems which sustain our livelihoods and well-being. If they are to continue being a source of future life and prosperity, these resources must be protected. Protecting the North American environment is a responsibility shared by Canada, Mexico and the United States.
The Commission for Environmental Cooperation (CEC) is an international organization whose members include Canada, Mexico and the United States. The CEC was created under the North American Agreement on Environmental Cooperation (NAAEC) to address regional environmental concerns, help prevent potential trade and environmental conflicts and to promote the effective enforcement of environmental law. The Agreement complements the environmental provisions established in the North American Free Trade Agreement (NAFTA).
The CEC accomplishes its work through the combined efforts of its three principal components: the Council, the Secretariat and the Joint Public Advisory Committee (JPAC). The Council is the governing body of the CEC and is composed of the highest-level environmental authorities from each of the three countries. The Secretariat implements the annual work program and provides administrative, technical and operational support to the Council. The Joint Public Advisory Committee is composed of fifteen citizens, five from each of the three countries, and advises the Council on any matter within the scope of the agreement.
Mission of the Commission for Environmental Cooperation
The CEC facilitates cooperation and public participation to foster conservation, protection and enhancement of the North American environment for the benefit of present and future generations, in the context of increasing economic, trade and social links among Canada, Mexico and the United States.
Global Programme of Action Coalition for the Gulf of Maine
VisionA healthy marine and coastal environment in the Gulf of Maine where human use and biological diversity thrive in harmony.
Mission
The GPAC will work with all interested parties to assist in the application of the Global Programme of Action for the Protection of the Marine Environment from Land Based Activities (GPA). This Coalition will draw from and build upon the existing work of the Gulf of Maine Council, the Regional Association for Research in the Gulf of Maine, the Commission for Environmental Cooperation (CEC) and other organizations and individuals committed to the protection of this shared public resource of world-class cultural, economic, ecological and intrinsic value.
The GPAC will assist public and private entities in the Gulf of Maine region identify pollution and habitat priorities and work to strengthen the capacity of these organizations and individuals to address them.
1998 Objectives
Identify and assess current knowledge on the marine and coastal habitats of the Gulf of Maine and the existing and potential effects of pollutants from land based activities on their sustainability.
Organize a workshop of multidisciplinary and cross-sectoral participants to review this knowledge and produce a consensus list of the priority pollutants and critical habitats in the Gulf of Maine requiring immediate action.
Identify strategies and measures related to the management of priority pollutants and critical habitats identified during this first workshop.
Organize a second workshop of multidisciplinary and cross-sectoral participants to assess management strategies and produce a regional response with immediate and long-term measures intended to reduce pollutants and protect and manage habitat in the Gulf of Maine. It will include financing mechanisms and a process for review and evaluation of implementation success.
Secure resources from interested stakeholders to begin implementation of actions to advance the elements of the Action Plan.
Results (late 1998-early 1999)
Broad-based, cross-sectoral stakeholder consensus on regional habitat and pollutant priorities and commitment to responding to them.
Implementation begins, within and across jurisdictions, including select demonstration projects.
Transitional seed financial support from the CEC for implementation.
Strengthened binational commitment to GPA implementation.
Conclusion of GPAC role as regional stakeholders initiate implementation.
Some 3.6 million people dwell in the coastal regions rimming the Gulf of Maine (Dow and Braasch 1996). It is safe to say that all derive some degree of benefit from living near a healthy productive marine ecosystem. The livelihood of many depends on the diverse and valuable harvests of finfish, shellfish and marine plants. In recent years fisheries in the Gulf have directly involved some 20,000 individuals in harvesting over 500,000 metric tons of fish and shellfish valued at $650 million (US) each year (Apollonio and Mann 1995). The indirect economic impacts of the fisheries are many times this. In recent decades the farming of fish and shellfish has become a major industry in many coastal areas. Aquaculture is an industry whose existence depends on the quality and productivity of nearshore waters. The shorelines and waters of the Gulf also provide a wide range of recreational opportunities for most residents, and each year several million tourists flock to the region to share many of the same seashore recreational pursuits. The Gulf is also an important corridor for commercial shipping, as evidenced by the many busy ports scattered around its perimeter. With due respect for their finite assimilative capacity, the productive and endlessly circulating waters of the Gulf can also continue to safely disperse and degrade some of the wastes generated by human populations. There seems little doubt that our incentives for sustaining a healthy and productive ecosystem in the Gulf of Maine should be many and compelling.
However, there are indications that the health and productivity of this valued marine system are being increasingly compromised by a wide range of human activities occurring along its coasts and throughout the Gulf's immense watershed. These stresses on the ecosystem are not all of recent origin; many have been steadily building in the centuries since the first European occupation of the region in the early 1600s. The early aboriginal inhabitants were relatively sparse, used simple technologies and thus had minimal impacts on coastal ecosystems. In contrast, Europeans, almost from the outset, began altering the natural landscape on a massive scale. As populations expanded and technologies advanced during the ensuing centuries the rate of alteration of the landscape increased rapidly (Gordon 1989). Although there is little quantitative information about the early state of the Gulf's coastal ecosystem, historical accounts unequivocally show that many coastal fish and wildlife populations have since been decimated and large tracts of once productive marine habitats lost or degraded. Even so, many of these ecosystem perturbations in the Gulf are still relatively minor in comparison to the severe impacts evident in many other coastal regions around the world. Significant areas of the Gulf can even truthfully be characterized as still "relatively pristine and healthy" (Dow and Braasch 1996).
The most pressing problems are largely confined to coastal waters, particularly in estuaries and harbors (Dow and Braasch 1996), and in areas where populations densities are high or rapidly expanding. However, if the environmental health of significant coastal ecosystems continues to deteriorate, it is likely that in time the ecological integrity and productivity of much of the Gulf may be compromised. Concerted efforts are needed to stem the alarming rate of habitat loss and, where feasible, to restore some of the critical ecological functions to degraded habitats. Many of the undesirable habitat changes that are occurring are clearly a direct consequence of land-based human activities, not only in coastal areas but throughout the watershed. It may be possible to reduce or reverse the adverse impacts of some of these activities on coastal habitats if we act promptly to better understand the causes and effects and take decisive steps as a society to better manage our social and economic affairs.
The goal of this scoping paper is to present an overview of the land-based activities associated with human occupation of the Gulf of Maine area that may be contributing to loss or physical degradation of important marine habitats. The pervasive effects of contaminants are dealt with at length in a companion scoping paper. As well as reviewing the available scientific literature concerning the environmental issues, the paper also considers the views of knowledgeable residents and groups in the region about habitat changes and the land-based activities that may be responsible. To be successful, any efforts to resolve the environmental problems besetting the Gulf must involve, and have the support of, citizens and their communities and must address their particular concerns and aspirations. The report concludes by identifying several important environmental issues, tentatively ranking them and making some preliminary recommendations for appropriate management objectives and actions for dealing with them.
The Global Program of Action for the Protection of the Marine Environment from Land-Based Activities (Global Program of Action or GPA), was adopted by the United Nations Environment Program on November 3, 1995. The GPA aims to prevent the degradation of the marine environment from land-based activities by promoting and facilitating the preservation and protection of the marine environment by States. It is designed to assist States in taking actions, individually or jointly within their respective policies, priorities and resources, which will lead to the prevention, reduction, control and/or cessation of the degradation of the marine environment, as well as to its recovery from the impacts of land-based activities. Achievement of the aims of the Program of Action will contribute to maintaining and, where appropriate, restoring the productive capacity and biodiversity of the marine environment, ensuring the protection of human health, as well as promoting the conservation and sustainable use of marine living resources.
The GPA calls for actions by each signatory nation to preserve and protect the marine environment on a national, regional and international basis in order to reach the goal of "sustainable seas". In North America, the Commission for Environmental Cooperation (CEC) was created as a result of NAFTA (North American Free Trade Agreement) negotiations to facilitate cooperation and public participation and to foster conservation, protection and enhancement of the North American environment.
In pursuing its mandate, the CEC decided to promote a series of pilot projects in North America to implement the GPA, and selected the Gulf of Maine (GOM) as a candidate site for one of the projects. CEC brought together an diverse group of individuals with an interest in the GOM and the GPA to develop and implement a project of their own design, with some support from the CEC. The group, which has named itself the GPA Coalition on the Gulf of Maine, has formulated an action plan to this end. A key component in the plan is a workshop in Saint John, New Brunswick on April 29 and 30, 1998 at which participants will focus on prioritizing habitat issues in the Gulf of Maine. The participants will include industry, community groups, municipalities, scientific institutions, and provincial, state and federal governments. This scoping paper has been prepared to assist participants at that workshop by providing background information on land-based activities and related habitat issues and by recommending possible management objectives and actions for consideration.
3. Approach and sources of information
The intent of this scoping paper is to provide an overview of the information available about land-based activities and their potential effects on marine habitats in the Gulf of Maine. The land-based activities considered are defined and described in section 4, while the habitats and habitat issues are dealt with in section 5. Based on an assessment of the scientific information, and on a consideration of community concerns, several priority issues are identified in section 6 and a number of possible management objectives and actions are outlined in section 7. A number of factors often obscure the causal links between land-based activities and observed habitat degradation and loss. These factors include confounding natural processes, such as ecosystem variability involving unpredictable, cyclical or progressive changes, multiple sources of stress involving cumulative or synergistic effects, as well as a suite of complex and poorly known intermediary processes such as eutrophication , sediment dynamics, hydrology and habitat regeneration. Some of these are briefly described in section 4.7 in order to explain the overall approach used in this scoping paper .
Because of this difficulty in obtaining unequivocal evidence to link most land-based activities with specific changes in habitats, this report adopts a two-pronged approach. First it looks at various land-based activities and the possible environmental stresses generated that could perturb marine habitats (section 4) . Then it looks at the principal habitat types (section 5) and attempts to identify the stresses that might potentially be associated with particular land-based activities. Finally, by assessing the situation from both these perspectives, it uses an activity-habitat matrix to provide aN assessment of the probable significance of ecological impact linkages between specific land-based activities and particular marine habitats. This involved A review OF the voluminous scientific literature available and consultation with specialists in many fields.
In addition to an examination of the scientific data, two other sources of information about the potential impacts of land-based activities on marine habitats in the Gulf of Maine were considered. To gauge general community perceptions of what habitats are being lost, degraded or at risk in their local area, and which land-based activities are considered to be environmentally threatening, we interviewed knowledgeable representatives from 48 different groups distributed widely around the Gulf. These included conservation, environmental, First Nations, fisher/harvester, industry and research groups (Appendix 1). A standard questionnaire was used for the phone interviews (Appendix 1). Complementary information on habitat degradation and land-based activities was also extracted from detailed compilations of information on all major Gulf of Maine Estuaries being prepared by the Conservation Law Foundation (Shelley in press) and the Conservation Council of New Brunswick (Harvey in press) for the Gulf of Maine Estuaries Restoration Project component of the Restore America's Estuaries Program. The detailed information on each estuary had been compiled with the assistance of individuals particularly knowledgeable about the local area and its environmental issues. The information obtained from the interviews and the estuary compilations was first analyzed separately and then combined to provide an overview and relative ranking of community concerns regarding habitats at risk and human activities responsible. These preliminary rankings of community concerns were then carefully considered in conjunction with the available scientific information about the probable significance and extent of linkages between causes and habitat effects and by this means a series of priority issues for the Gulf region was identified and ranked. The ranking was based on a somewhat subjective assessment of the combined socioeconomic and ecological significance of the issues identified.
4. Overview: land-based activities in watershed/coastal zone
Human activities immediately adjacent to the coastal zone typically have the most devastating and readily observable impacts on estuarine, intertidal and inshore habitats. However, it is increasingly being recognized that activities throughout the 179,000 km2 of land area that drains into the Gulf (Dow and Braasch 1996) can significantly effect coastal habitats, often in subtle and poorly understood ways. The waterborne transport of industrial contaminants and other noxious materials is particularly worrisome in this regard, and is treated at length in the contaminant scoping paper. In addition, there are a variety of physical alterations in habitats, involving either degradation, actual loss or functional loss that can also be attributed to human activities in the watershed. It is these physical effects that will be considered here. The land-based activities discussed are largely those identified in the Global Plan of Action (UNEP 1995). However, an activity not specifically identified in the GPA; namely heavy mobile fishing gear use in inshore waters, is also considered because of growing scientific and public concern about the threat posed to inshore benthic habitats by what is arguably a land-based activity.
4.1 Population growth and urbanization
The culture of human activities includes both intentional actions that involve decision-making as well as largely unintentional ones such as growth in population. Growth in population has a fundamental influence on the health of coastal habitats. Perhaps more significantly, growth in another dynamic process; namely urbanization, often far exceeds the numerical growth in population. Population growth and urbanization are distinct and synergistic processes calling for different response strategies. There will inevitably be population growth and increasing urbanization in the Gulf of Maine region. Whether this involves growth in population, no growth but changes in land use, or a relative population shift to the coastal zone, increasing human activities and changes in patterns of land use will have steadily growing impacts on coastal habitats. A pervasive concern associated with coastal development is the cumulative impacts not only on the environment but on the economy and community identity. Though this paper focuses primarily on habitat impacts, it is important to keep in mind these broader economic and social implications of habitat loss and degradation.
The coast has traditionally been the area of concentration of population worldwide, and is also the area of the United States where growth, three times the national average, is at its highest (Colliton et al. 1992; LMER 1992). The population density within 50 miles of the Gulf of Maine varies greatly in different regions, from 0.1 to 10,000 people per square kilometer (US Census Bureau 1996), with Massachusetts coastal counties accounting for two thirds of the total population (Colgan 1989). This differential is expected to continue to increase, with the three US states growing at four times the rate of New Brunswick and Nova Scotia (Colgan 1989). Projections suggest that the New Hampshire population will increase by 25% by the year 2025, while those of Massachusetts and Maine will rise by 15% (ACBJ Research 1997). Growth rates will be highest along the coast as far north as Lincoln County, Maine, with much lower, stable or even negative growth rates in Northern Maine and the Canadian provinces (Colgan 1989).
The coastal populations are increasingly becoming concentrated in a few major centers and, perhaps not surprisingly, environmental problems are most acute in these same areas (Dow and Braasch 1996). The major centers of population grouped in four descending size categories are 1) Boston; 2) St. John and Portland; 3) Moncton, Bangor, Lewiston, New Bedford and Fall River; and 4) Truro, Waterville, Augusta, Bath, Brunswick, Biddeford, Dover, Portsmouth, Haverhill, Lawrence, Gloucester, Salem, Lynn, Cambridge, and Quincy (Rand McNally 1993). Boston is by far the largest urban center on the Gulf coast and, together with St. John and Portland, is significantly greater in population density so as to have very different impacts on coastal habitat than the smaller centers. However, Boston and St. John are presently experiencing low growth rates or even declines in population. which could eventually affect their financial ability to adequately address ecological problems (Colgan and Plumstead 1995).
Urbanization is not limited to the larger urban and suburban centers, but is spreading through many rural counties. Projections indicate that two of the three largest urban centers will not be absorbing a proportionate amount of the anticipated rise in the population of Gulf region, and that increases in counties immediately north of Boston will not exceed the state average. In Nova Scotia, due to its compact geography, Halifax, located on the Atlantic coast, is catalyzing growth in three counties bordering the Bay of Fundy (Colgan and Plumstead 1995). A trend in both countries that could have a major impact in the Gulf region is the marked increase of micropolises , or centers of 10,000 to 50,000 population (ACBJ Research 1997). This can be anticipated throughout the region given the abundance of attractive small towns along the coast. Another trend is a rapid increase in the proportion of housing starts in rural counties. In the Gulf of Maine area, this is significant in at least one county and possibly in others. On Cape Cod housing starts have increased at a rate of 36% compared to the state average of 10%, with Boston itself slightly below the state average (Valiela et al. 1992). These trends are fueled by rising incomes in urban centers, where the per capita income increases are the highest in the Gulf region (Colgan and Plumstead 1995). In the urbanizing rural counties, growth in housing starts is parallel to economic growth in the trades and services sector, which takes up somewhat more land than an equivalent economic growth in the manufacturing sector (Colgan 1989). This multiplies the effect of population growth substantially. Based on studies of rural New York and Connecticut counties, it has been shown that urban land use expanded at a rate up to eight times greater than the population growth. With urban land patches fragmenting the landscape at an increasing rate, the EPA has now identified landscape fragmentation as one of its top priorities (LaGro 1994; Chester Arnold pers. comm.). In many regions of the Gulf, rural counties will increasingly be called upon to deal with pressure of increasing urbanization and landscape fragmentation with an infrastructure and bureaucracy ill-equipped to handle it.
Land use planning responses to coastal development in different parts of the Gulf of Maine is varied, ranging from few, mostly ineffective, controls to very stringent ones that are strictly enforced. However, there is a growing recognition of the need for more effective protection of the coast and for better control of growth and development. There is rising interest in the development and use of innovative approaches to the problems. For example, the Massachusetts Bays Program has created a water quality modeling tool called FecaLOAD to estimate the fecal coliform loading from storm water runoff. It has been successfully applied in Casco Bay. New Brunswick proposed a provincial coastal policy that addresses development and use of the coast and inshore waters. Brunswick ME enacted a Coastal Protection Zone applicable to fragile coastal embayments. A 1988 study had shown that a severe shellfish kill was caused by nutrient loading from municipal waste water, septic fields, fertilizers and stormwater runoff. The new zoning proscribes setbacks, larger lots, improved septic design and maintenance and fertilizer use (Vestal and Rieser 1995). There are similar examples from throughout the region, suggesting that the desire for positive change is strengthening.
Ecological implications of urbanization and development
A poll of 333 coastal zone specialists at the Coastal Zone 97 Conference in Boston revealed that concern for the issue of existing and emerging megacities outweighed that for climate change by 73% (Intercoast Network 1998). Likewise, the issue of development, population growth, and human activity in the Gulf of Maine coastal zone is perceived as one of the greatest threats to the health and degradation of the coastal habitats and their associated economies. Human land use activities and urbanization causes increased habitat fragmentation, degradation and loss in the coastal zone by:
- replacement of natural habitats with buildings, roads, recreational facilities and artificial landscaping
- the introduction of domestic flora and fauna into natural habitats
- diminished productivity; loss of coastal agriculture, forest and wetlands
- non point source pollution carried by storm water runoff
- protective measures such as construction breakwaters, dams and barrages and draining, diking or infilling of flood plain areas etc.
These latter are especially prevalent near urban centers where land (for commercial, industrial and residential needs) and land prices are at a premium (C. Drysdale. pers. comm.). Public access sites, recreational use (see section 4.6) and residential development is increasing along the shoreline and on coastal islands (see section 5.7). Developers recognize the value of living on the coast and consequently perpetuate sprawl development, raising many issues related to private and public property rights. States and provinces have taken steps to ensure public access to the shore by establishing and maintaining park sites, access sites, and planning for future parks and access (written into many local and regional land use plans and strategies). In some areas it has included shorefront acquisition and improvement projects such as expanded or upgraded parking facilities, boat docking facilities and beach access.
Many studies have indicated that another major effect of urbanization is the dramatic reduction in the extent of permeable landscape (Yamaguchi and Tyrell 1997). Streets, parking lots and roofs make up a substantial proportion of the new human landscape. It has been estimated that runoff doubles when natural ground cover is replaced by 10-20% impermeable surface (Intercoast Network 1998). In the Tidelands region of Connecticut, research for the Chester Creek Watershed Project showed that there is a strong correlation between the amount of impervious surfaces (concrete, asphalt, rooftops) in a watershed and the health of a receiving stream. Even in a watershed with a largely rural character, large-lot residential zoning, and extensive open space, the potential exists for significant degradation of water resources (Nelson and Arnold 1996).
Other concerns that are associated with expanding coastal development include:
- ecosystem and site specific health implications such as bacterial contamination from sewers, overboard discharge and urban stormwater runoff which results in periodic closure of shellfish areas to harvesting and beaches to swimming
- use and diversion of fresh water from coastal areas and its impact on the quality and quantity of potable water. This is of great concern with the increased development on coastal islands
- port and harbor development is increasing and major centers are developing strategies ranging from site specific (small bays and marinas) to comprehensive plans that consider adjacent areas of land and water that are impacted by the port activities and development (Boston Harbor). In most areas the principal focus is on human use and less on ecosystem concerns (see section 4.2 regarding port dredging).
A disturbing trend in the last two decades has been an increase in shellfish bed closures near suburban and rural areas (NOAA 1986; 1991). For example, in Maine many of the 255,608 acres of shellfish beds are periodically closed to harvesting, and other coastal areas are often closed to swimming, because of bacterial contamination (Maine State Planning Office 1997). Urbanized land use is also a significant contributor to non point source pollution and nutrient loading of the coastal waters. In Waquoit Bay, domestic waste water from septic tanks provides more nitrogen than precipitation or use of fertilizers. This is compounded by the deforestation attendant with urbanization (Valiela et al. 1992; Valiela and Costa 1988; Persky 1986).
marine debris
Urban centers also generate a great deal of garbage and other solid wastes and inevitably some proportion of it finds its way into the marine environment. Marine debris is pervasive throughout the Gulf of Maine. Marine debris comprises " any man made substance that enters the marine environment that does not readily biodegrade" (EPA website <http://www.epa.gov/owow/estuaries/coastlines/coastlines6.3/ marine.html>). It is not know how much marine debris there is in the Gulf as a whole, because an unknown proportion of it is "at sea", either on the bottom or floating offshore. The only real indication of the scope of problem is the substantial quantity that continually washes ashore. Volunteer beach clean up programs, of which there are many around the Gulf, not only remove much debris from shorelines, but also provide valuable information about the nature of the debris. This is important for identifying general sources and in designing effective strategies to reduce inputs. Typical beach sweeps shows that the debris comprises plastic (59%); paper (12%), glass (12%), metal (11%), wood (3%), rubber (2%), cloth (1%) (Centre for Marine Conservation Web Site: <http://cmc-ocean.org/mdio/sources.html>). Plastic, glass, metal and rubber are considered persistent debris because they are not readily degraded. The surveys suggest that 70-80% of the material comes from land-based sources, with much of it apparently washed through storm drains, trash from beach goers and material dumped illegally. The remainder comes from marine sources, typically, commercial fisheries, recreational boating and large vessel operations, particularly cargo ships.
Plastics are of great concern, because of the volume involved and the nature of the material. The features that make them so useful and widely used; namely their lightness, versatility, low cost, durability and strength, are the very things that make them a problem in the marine environment. Much of the plastic found is some form of packaging material, (bottles bags, lids etc.) or fishing gear (nets, rope, floats, pails etc.). The discarded nets, ropes and traps as well as cargo vessel wastes such as plastic strapping bands are particularly worrisome because they entangle and kill fish, turtles, birds and mammals. One beach survey also revealed that entanglement in fishing line discarded by recreational fishermen accounted for one third of all entangled animals found (CMC Web site). Some plastic debris (especially plastic bags and small fragments of Styrofoam) is often mistaken for food by marine animals and ingested, causing varying degrees of distress or death. In addition to being an aesthetic problem, debris on beaches also interferes with their recreational use by humans, sometimes at considerable cost. It is estimated that beach closures due to the presence of garbage and biomedical wastes resulted in the loss of over a billion dollars in tourism revenue in New York and New Jersey in 1987-88 (EPA Web site).
Controlling marine debris is difficult. Most jurisdictions in the region have regulations to control waste disposal and shoreline dumping, and treaties such as the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78 Annex V) regulate the disposal of garbage at sea. However, the laws are difficult to enforce and it is virtually impossible to identify the specific sources of most debris, as it can travel great distances with currents. Public education, local litter control programs and volunteer clean up initiatives, probably offer the best hope for improving the situation in the long term. The Gulf of Maine Council on the Marine Environment has been in the forefront of many such efforts in the region (GOMCME 1996).
Clearly we must manage human activities and land use more effectively in order to safeguard coastal habitats and resources. Direct relationships between some human activities and impacts are often easy to see and act on; but those involving, cumulative, indirect, incremental, time and space lag, and synergistic effects are not (Vestal and Rieser 1995). It has been the latter type of innocuous causes that have made it difficult to relate the health of the coastal zone to human activity (Odum 1970). This is evident in the Gulf of Maine region, where there has been some success in controlling point source pollution, but addressing the more subtle non point source pollution issues, such as nutrient loading; or cumulative sediment erosion and deposition, has been more difficult (Vestal and Rieser 1995). Further difficulties have arisen because of the way in which managers have traditionally addressed coastal environmental issues. Odum (1982) referred to it as "the tyranny of small decisions", in which a series of small, apparently independent decisions ultimately grew into large unanticipated decisions.
4.2 Alterations to coastal morphology
diking
When Europeans first settled around the Bay of Fundy in the early 1600s there were an estimated 395 km2 of tidal salt marsh, largely fringing the upper reaches of the Bay (Gordon and Cranford 1994). They were quick to recognize the agricultural potential of the rich marsh soils and were also well acquainted with European marsh reclamation techniques. Over the next two centuries, the greater part of these marshlands were diked with earthen barriers, drained and tilled for crop production. The history of these monumental reclamation efforts up to recent times is concisely told in a publication by the Nova Scotia Department of Agriculture and Marketing (NSDAM 1987). During the 1940s a major dike restoration program was begun in the Maritimes, and over the next 20 years some 373 kilometers of dikes, protecting over 33,000 hectares of farmland were repaired or constructed. During the 1950s and 60s tidal barrages were constructed on most of the rivers around the Bay. These served to protect upstream reclaimed marshland from tidal flooding and reduced the need for frequent, costly repairs to miles of protective dikes. Today only about 65 km2 of tidally flooded salt marsh remains (Gordon and Cranford 1994), a mere 16% of the original area. Although New England salt marshes were diked to a lesser degree, large areas have, nevertheless, succumbed to other reclamation activities such as infilling, draining and ditching (Nixon, 1982). In many areas, dikelands are now being used for industrial and residential purposes, a worrisome trend in view of their vulnerability to storm surges and sea level rise (Parks et al. in press).
Given the paucity of quantitative information about early ecological conditions in the Fundy region it is difficult to assess the impacts of these massive diking projects on the marine ecosystem. Undoubtedly they influenced sediment dynamics and benthic habitats over large areas. Many studies (Gordon and Cranford 1994; Gordon et al, 1985; Adam 1990) have demonstrated the important role that salt marshes play in releasing organic detritus, and thus in enhancing the secondary productivity of the adjacent marine ecosystem. We shall probably never know how much more productive these coastal ecosystems were when the marshes were as much as six times more extensive, but undoubtedly the enhanced agricultural production has been achieved at the expense of substantial marine production.
ditching
For centuries, throughout the Gulf region, many high salt marshes that escaped diking have been heavily used as pasture for livestock or harvested as salt hay for fodder. Many of the early settlement patterns in New England were largely dictated by proximity to such hay marshes (Nixon 1982). In order to facilitate the harvest, many of these productive marshes were crisscrossed with ditches several decades ago to drain the land. In other marshes, particularly those near heavily populated areas, even deeper ditches were excavated in an effort to remove standing water to control mosquito populations. Such ditching projects were particularly prevalent during the depression as make work programs, so that by the late 1930s about 90% of the marshes of the northeast US coast had been extensively ditched (Nixon 1982). Such excessive drainage severely impaired the natural functioning of the salt marshes. Some of the adverse habitat impacts of grazing, harvesting and ditching are described in Nixon (1982) and Adam (1990). Now, with little market for salt hay and improved methods of mosquito control, there is growing interest in blocking the ditches in some marshes in an effort to restore some of the ecological functions.
infilling
A century or more of infilling of coastal wetlands with rock, soil and other material has already resulted in the irretrievable loss of large areas of many types of coastal habitat, particularly in the more populated areas of the Gulf (Platt et al. 1995a). Dredge spoils were often pumped directly onto salt marshes to create new land for industrial or residential development. For example, in Wells Harbor ME, 90 acres of marsh were filled with sediments dredged from the river during creation of a harbor (Van Dusen and Johnson Hayden 1989). Eelgrass beds and benthic habitats are also vulnerable to such infilling (see sections 5.8 and 5.10). In recent decades there has been a growing appreciation of the ecological value of such wetlands, and in most jurisdictions legislation now largely protects such areas from large-scale direct encroachments (Dow and Braasch 1996). However, there are indications that small-scale encroachments still occur in many places, both legally and illegally, as private landowners seek to expand or protect valuable and vulnerable coastal properties. Such small, incremental losses of marine habitat, seemingly innocuous in themselves can have substantial cumulative impacts over time.
dredging and spoil disposal
Dredging, widespread in many parts of the Gulf of Maine, involves removing large volumes of sediment, often to a depth of several feet, from the ocean floor and depositing it elsewhere, either on land or in coastal waters. Two methods of dredging are currently widely used. Mechanical dredging employs large scoops or conveyers to physically scoop up sediment and place it in a barge for transport to a dump site. Hydraulic dredging involves loosening the sediment with water jets or rotating cutter heads to create a slurry, which is then pumped into a barge or directly through a pipeline to a disposal site. This latter is the most efficient, economical and commonly used (Kennish 1992). Dredging is routinely carried out in major port areas to maintain adequate draft for commercial vessels. Thus Boston, Portland, Portsmouth and St. John harbors have been regularly dredged over many decades. At present, a proposal for another major dredging program in Portland Harbor is being considered (Shelley in Press). Other navigable waterways such as the Cape Cod Canal, Salem Sound and the Kennebec River as far as Augusta, as well as many smaller ports, are also periodically dredged to remove accumulated sediments. Since 1968 almost a million cubic yards of subtidal sediments has been dredged from the Kennebec estuary and it is anticipated that at least another 600,000 cubic yards will be removed over the next 25 years (Shelley in press). Even areas remote from large ports may be subject to regular dredging activity in an effort to enhance recreational boating and support the development or expansion of marinas. Thus in 1974, over 11 acres of subtidal habitat in Bucks Harbor, Machias Bay was dredged to enhance access for recreational boating (Shelley in press). Similar dredging has taken place in parts of Casco Bay as well as in many of the other tourism "hotspots" along the coast.
Dredging may adversely effect estuarine and coastal habitats in a number of ways. These include primary, direct effects on benthic habitats, secondary effects on water quality and a variety of poorly understood indirect tertiary effect (Kennish 1992). The most devastating effects are clearly on benthic habitats, where the habitat and its biological communities are removed and destroyed, and on the terrestrial or submarine habitats that may be smothered by the dumped dredge spoils. The rate of recovery of the sediment structure and biological communities in the affected habitat varies with the nature of the habitat and the extent of the disturbance. Recovery of the benthic habitat from a major perturbation usually involves a series of successional stages (Rhodes et al. 1978), and typically, the same species assemblage returns to the area over time (Kennish 1992), unless the sediment composition has been drastically altered. Estimates of recovery times of animal communities in various places range from 6 months to over 3 years (Kennish 1992). Frequent dredging of an area may prevent the habitat from recovering to a stable, long-term equilibrium state.
A variety of secondary effects can adversely impact nearby habitats. Plant communities, such as eelgrass beds, not directly destroyed by dredging may be extensively damaged by slumping of sediments near the dredge site(Fred Short pers. comm.) and growth and survival over even more extensive areas can be impaired by turbidity and sediment deposition (Kennish 1992). Excessive fine sediment deposition can also smother shellfish beds and other subtidal and intertidal habitats. The dredging activity may also resuspend long-buried organic matter, nutrients and contaminants causing increased turbidity, eutrophication, increased biological-oxygen-demand as well as toxic effects on sensitive species (Engler 1990). Even more indirect and unpredictable tertiary effects on currents velocity and direction and on sediment transport may occur as a result of significant alterations of bottom topography as a result of dredging (Dow and Braasch 1996). This could in turn alter nearby benthic habitats or enhance erosion of sand beaches or estuarine shoreline.
Against these many negative impacts of dredging must be weighed a few possibly beneficial ecological effects. These include enhancing water circulation in estuaries, increasing the concentration of nutrients in the water and removing contaminated sediments from benthic habitats(Kennish 1992). For example, in Blue Bay in Maine the bottom sediments contain large amounts of sawmill wastes and contaminants that are undoubtedly adversely effecting the inshore benthic community (Shelley in press), and removal of these wastes by dredging might enhance the habitat in the long run. Dredging has also served to provide a ready supply of inexpensive material for use in landfilling or beach nourishment. However, the manner of disposal of such dredge "spoils" is a contentious issue, as existing habitat is inevitably smothered and destroyed. In fact, spoil disposal issues are becoming of even greater concern that the actual dredging itself. Contaminated sediments are nowadays virtually all deposited on terrestrial sites (Kennish 1992), but rarely, if ever, on coastal marshes and wetlands. Clean sediment is often disposed of in selected open water locations where it either remains (retentive sites) or is washed away by currents (dispersive sites). Some of the extensive research that has been conducted by the US Army Corps of Engineers on the impacts of dredging and spoil disposal on coastal habitats is summarized in Kennish (1992).
groins/jetties/and breakwaters
Humans have extensively modified coastlines in many part of the Gulf by constructing a variety of coastal structures for purposes ranging from shoreline protection to enhancement of shipping access. These structures include groins, breakwaters and jetties or wharves. Groins are barriers, set at right angles to the shore, usually extending from the backshore well into the subtidal zone (Lowenstein 1985). They may be constructed of timber, steel, concrete and/or quarry stone. These structures are designed to retard sediment loss or to trap sediments drifting along the shore, preventing erosion of an existing beach or creating a new one. Sometimes a series of them are constructed, forming a groin field or system , along a length of shoreline needing protection. Although they are usually effective in fulfilling their primary function of stabilizing the immediately adjacent beach, they more often than not exacerbate the erosion of beaches further down-current along the shore (Bird 1983).
Jetties are usually constructed near the mouths of inlets, bays or rivers to stabilize the navigation channel by controlling sediment movements, shield vessels from waves and provide a convenient place for docking vessels. Like groins, they may be constructed of timber, steel, concrete and/or quarry stone, and may in a similar fashion enhance erosion of downstream beaches or flats. Breakwaters are similar barriers, primarily designed to protect land or water areas behind them from the direct influence of waves. They may be constructed from a variety of readily available materials ranging from sunken ships to large concrete-filled fabric bags. There are two main types of breakwaters. Shore-connected ones protect a shore area, harbor, anchorage or basin from wave attack. Offshore ones are usually oriented parallel to the shore to provide wave protection to the shoreline in the lee of the structure.
Many thousands of these types of structures have been constructed in bays, inlets and estuaries along the length of the Gulf of Maine coast over the past two centuries or so. Many have virtually disappeared over the years, their resistant skeletons often a bleak reminder of changing economic circumstances. Large numbers of others have been all but abandoned and are poorly maintained and in various states of decay. They have all had, and most continue to have, an influence on the currents and the sediment dynamics in their immediate vicinity and thus on the structure of nearby subtidal and intertidal habitats (Mulvihill et al. 1980). The cumulative effects of such structures on marine habitats, especially when considered in relation to the many other structures usually found nearby that impede currents or restrict tidal incursions, may be significant. However, the ecological effects of such small-scale structures have not been well studied.
armoring of shorelines
In many areas around the Gulf, where coastal erosion or storm wave attack threatens valuable real estate, various forms of protective structures have been constructed along the shoreline. Bulkheads, revetments and seawalls are all soil or sand retaining structures, designed to resist wave attack and are variously constructed of steel, wood, concrete, gabion baskets, quarry stone or rubble. Such structures are often built adjacent to vulnerable beaches and dune systems as described in section 5.4, where they often cause unforeseen problems (Lowenstein 1985). The total extent of coastline affected by various types of armoring is difficult to assess, as are the impacts of the structures on nearby intertidal and subtidal habitats. Most such structures have been in place for many decades or more, and marine habitats in their vicinity have undoubtedly long since attained a new equilibrium. There is a growing recognition that in many instances such protective armoring may be ecologically inappropriate. Maine, for example, now bans the construction of new seawalls on sand beaches, although existing ones can be maintained (Lowenstein, 1985; Joseph Kelley pers. comm.).
beach replenishment
In many parts of the southern Gulf, wide sand beaches are critically important to the local tourism industry. Where such beaches are being rapidly eroded by waves and currents a program of beach nourishment or replenishment is often initiated. This involves importing large volumes of sand from terrestrial or marine (dredge spoils) sources to replace that being lost. In most situations such replenishment is little more than a quick fix, as the erosional forces are still present, and sometimes the imported sand erodes away even quicker than the native variety, leading to a ceaseless round of replenishments (Lowenstein 1985). The potential ecological impacts of such replenishment of sand beaches are explored more fully in section 5.4.
4.3 Hydrologic alterations/tidal restrictions
dams
Dams are barriers, generally of rock or concrete, built across watercourses primarily to impound freshwater in upstream headponds for purposes of power generation, agricultural irrigation or downstream flood control. Most are fitted with mechanisms for releasing water in a controlled fashion. Over the past two centuries dams of varying sizes and types have regulated the patterns of flows of almost every significant river entering the Gulf of Maine. Early on, many dams were built to provide mechanical power for the thousands of sawmills that sprang up to supply lumber for the booming shipbuilding industry (Platt et al. 1995a). Many other industries also depended heavily on water power, so it is not surprising that population centers developed and expanded rapidly on the rivers where most such industries tended to concentrate. Later, dams were primarily built for the generation of electricity and to regulate downstream water levels to prevent flooding. Inevitably, their greatest proliferation has been in areas of greatest population densities and industrial activity; namely, the more southerly regions of the Gulf (Gordon 1989). Many rivers today have several dams along their length. For example the Saco River in Maine has 11 dams along a 70 mile stretch, while the Union River in eastern Maine reportedly has 42 dams along its length (Shelley in press).
The damming of rivers inevitably has important ecological repercussions, both upstream and downstream of the structure, largely as a result of interference with the transport of both water and waterborne sediments. By reducing the volume and rate of freshwater flow, and also by altering the patterns of flow at different times of the year, dams can significantly alter the hydrologic regimes in estuaries far downstream as well as in adjacent coastal waters. (Carter 1988). The changed flows can influence mixing and circulation patterns, salinity distributions, ambient water temperatures, ice formation and breakup and also nutrient concentrations (Fefer et al. 1980; Carter 1988; Platt et al. 1995a). The precise nature of these effects at specific dam sites are poorly understood because of the complexity of the dynamic processes involved.
Dams also impede the natural movements of sediments in the river, both in terms of bed transport (along the substrate) and suspended sediment transport (Carter 1988). Headponds often serve as a sediment trap and thus the dams interrupt the normal sediment supply to estuaries and nearby coastal areas. As a result, estuarine and coastal habitats that rely on a dynamic balance between sediment supply and loss, such as salt marshes, mudflats and sand beaches, can undergo dramatic alterations in extent. The precise nature of these changes are also poorly understood, particularly over the longer term. Ongoing studies of sediment dynamics in the upper reaches of the Bay of Fundy by Amos and his colleagues (see Daborn 1997 and Greenberg et al. 1997 for overviews) are providing many useful insights about the factors contributing to sediment stability, erosion and transport and thus are expanding our predictive capabilities. Reductions in water velocities upstream of the dams can also enhance deposition of fine sediments that smother and effectively destroy the clean gravel spawning beds required by many species of anadromous fish for successful egg development (Dow and Braasch 1996). The magnitude of the ecological impacts of such changes in water flow and sediment dynamics are strongly influenced by local conditions and operational practices. Most dams have been in place for many decades or more, and thus information about prior habitat conditions and the nature of subsequent ecological impacts is largely informed speculation or based on anecdotal reports..
Even when dams do not result in the smothering of fish spawning habitat, they can effectively impede or block the passage of anadromous fish migrating from their marine feeding areas to those critical riverine spawning areas. In such situations there is a "functional loss" of habitat rather than a real physical loss. Although a variety of other stresses have undoubtedly contributed to the serious decline in Atlantic salmon numbers in rivers throughout the Gulf of Maine (Cutting et al. 1994; USFWS 1995), it is likely that dams have also played an important role by causing the actual and functional loss of key spawning habitats. In most New England and Maritime rivers runs of anadromous alosids (principally American shad, Alewife and blueback herring) have also been adversely affected by dams and inadequate fishways (Rulifson 1994), and in Maine, shad runs have been rare since the early 19th century, when impassable dams were built on most large rivers. Dams and other such barriers are also thought to have been the principal cause of the dramatic declines in most other anadromous fish populations in Maine (Fefer et al. 1980), and this is probably true throughout the Gulf region. Some dams incorporate fishways in their design to facilitate the passage of migrating fish. However, studies have shown that even functional fishways prevent the passage of up to 10% of active fish such salmon (Fefer et al. 1980), while less energetic fish such as sturgeon, shad and striped bass probably fare much worse. Many dams throughout the region have no provision for fish passage, while many of those that do are largely ineffective, because of poor design, construction or maintenance (Shelley in press). Clearly there appears to be a critical need for the construction, upgrading or routine maintenance of fishways throughout the Gulf region.
Another option might be to breach or remove some of the dams that have long outlived their usefulness and have largely been abandoned. There are periodic proposals for the removal of such structures, such as on the Presumpscot River flowing into Casco Bay (Peter Milholand pers. comm.). However, there are concerns that such remedial action could initiate a new round of undesirable and largely unpredictable ecological impacts both upstream and downstream. Some of these concerns involve the release of large quantities of trapped sediments, as well as the possible remobilization of long buried contaminants. The short and long-term implications for critical riverine, estuarine and coastal habitats of any such mitigative efforts need to be carefully studied and weighed on a case by case basis before any dams are removed.
Tidal restrictions
On each rising tide, seawater surges into and over many coastal habitats; up creeks and rivers, into and over salt marshes, into protected embayments and through other narrow channels. However, during the past century this natural diurnal seawater movement has been increasingly impeded or diverted in many coastal areas around the Gulf by various , structures across watercourses, channels and wetlands. In every region causeways, road bridges, railroad beds, and other barriers block this tidal exchange, or reduce it by restricting flow to culverts or other narrow channels. In larger centers, such as Boston, Portland and St. John, the land-sea interface has been highly "engineered" over the past century or more and tidal restrictions abound. Even in many seemingly undeveloped estuaries and embayments road crossings, bridge abutments and other structures interfere with tidal flow and destroy or degrade vulnerable habitats. Their design, siting and construction have been determined almost exclusively by community needs, engineering or economic considerations, with little, if any, regard for the potential impacts on the integrity of, and ecological interactions between, the marine habitats the structures bisect.
For the Gulf as a whole there appears to be no comprehensive inventory of the many such structures that interfere with tidal flows, although some regional surveys have been undertaken. For example, half of the 125 tidal crossings in Essex Bay, MA were visually identified as possible sites of significant impedance of tidal flow, and 25 of the sites had a 5 inch or greater difference between the upstream and downstream tidal range. (Mountain et al. 1997). Most of the structures are many decades old and are reportedly poorly designed, sited and maintained (Shelley in press), and few have been evaluated regarding their adequacy in allowing tidal exchange. In almost all cases there is little or no information available about the nature of the impacts on nearby marine habitats or about the areal extent of the habitats affected. Benthic, water column and intertidal mudflat habitats in estuaries and coastal areas may all be directly or indirectly influenced by reductions in tidal exchange. The particular vulnerability of salt marshes to such tidal restrictions is discussed in section 5.2. It has been suggested that the adverse effects on marine habitats of many of these structures could be reduced or eliminated by enhancing tidal exchange by installing new culverts or by enlarging existing ones. (Burdick et al. 1994). However, each situation is unique and remediation needs have to be carefully assessed on a site by site basis.
Harvesting of natural resources has been a mainstay of local economies for centuries throughout the Gulf of Maine. Sometimes the marine habitats adversely affected may be far removed from the actual area of harvesting. Harvesting of resources far inland, as well as along the coast in the intertidal zone or in shallow coastal waters can have significant impacts not only on the resource species being harvested , but on critical wetland and marine habitats as well. In this section we briefly consider the nature and potential marine impacts of resource related activities such as forestry, agriculture, aquaculture, intertidal harvesting, subtidal harvesting as well as mining and submarine aggregate extraction.
forestry
Since the earliest days of European settlement forestry has been a major activity throughout the Gulf of Maine watershed. The history of this lumbering and the widespread impacts that it has had on the landscape of the region has been recently reviewed by Conkling et al. (1995) and Platt et al.(1995a). By the mid nineteenth century between two thirds and three quarters of the forests in the coastal regions had been cleared for settlement and agriculture, and much of the remainder was being intensively harvested to supply fuel and lumber. By this time agriculture in the region had begun to decline in importance and much of the cleared land reverted to forest, particularly around the northern areas of the Gulf. Today, large tracts of New Brunswick, Maine and New Hampshire are heavily harvested "industrial forests" (Conkling 1995) that bear little resemblance to the former mature forest ecosystems that dominated the area. These massive transformations in the natural landscape have over time been accompanied by changes in patterns of freshwater runoff into rivers and estuaries, as well as by increases in soil erosion and in the sediment loads transported into coastal waters. From todays perspective it is difficult to gauge the extent and the effects of these long ago changes in land cover on estuarine and coastal habitats. Today, forestry activities, along with agricultural practices, still contribute to the elevated sediment loading and hydrologic alterations reported in many rivers and estuaries.
The early forest industry also had other significant impacts on coastal habitats.. The first sawmill was built in 1623 in Berwick, Maine, and over the next two centuries water-powered sawmills sprung up on the banks of virtually every significant river flowing into the Gulf. Many of these involved the earliest efforts to alter river flow patterns with dams (see section 4.3). In addition, the mills released vast amounts of sawdust and bark chips into the river to join the large volumes of wood debris produced by the massive log drives on many of the larger rivers. The pulp mills that eventually began to supplant the saw mills also released large amounts of wood wastes as well as variety of other noxious materials into rivers and estuaries (Eaton et al. 1994). The potential impacts of these wood wastes on benthic habitats are discussed in section 5.8. Although the organic wastes and toxic effluents from modern mills are more carefully regulated, in the Maritimes the many pulp mills still produce more contaminated effluent than any other industrial source in the region (Eaton et al. 1994).
agriculture
Like forestry, agriculture has a long history in the Gulf of Maine watershed, particularly in the coastal regions which were settled first. The earliest European settlers began diking and draining the vast salt marshes and clearing the great forests of the region in order to expand agricultural production. Only about 15% of the original salt marshes remain in the Bay of Fundy region and less than half remains along much of the remainder of the Gulf of Maine coast (Burdick et al. 1994).. Much of the remainder of the salt marsh has been extensively ditched to facilitate salt hay harvesting or to control mosquitoes. Agricultural activities in the region reached a peak in the mid nineteenth century and subsequently the proportion of land devoted to agriculture declined with the opening up of western farmlands by the railroad and the end of the market for forage by the widespread use of the gasoline engine (Platt et al. 1995a). It is difficult to assess the nature and extent of the impacts of these early agricultural undertakings on the coastal ecosystems, but they were undoubtedly profound. Current trends in agricultural land-use in the region are being monitored as part of the NOAA Coastal Change Analysis Program (C-CAP). Although agriculture now encompasses a much smaller proportion of the landscape (Stevenson and Braasch 1994) it still significantly influences aquatic production, water quality and habitat integrity in riverine, estuarine and coastal waters. The most pronounced effects include contamination of aquatic habitats with an array of pesticides, inorganic nutrients and livestock wastes, as well as increased water runoff from tilled ground with an accompanying increase in soil erosion and sediment loads in rivers and estuaries. In some areas river water is diverted for irrigation and other agricultural purposes. For example, in important blueberry growing areas of Northern Maine substantial amounts of water are drawn from the Pleasant and Narraguagus rivers for growing and processing the crop, altering the flow of these rivers (Shelley in press).
aquaculture
One of the more dramatic phenomena that has taken place in the northern Gulf of Maine over the past two decades has been the rapid growth of the salmonid aquaculture industry. The development of fish farming in the region has been described in some detail (Cook and Black 1993 and Milewski et al. 1997). The industry was launched in southeastern New Brunswick in 1978, and by 1996 there were a total of 77 approved farm sites producing over 16,000 mt of salmon worth almost $120 million (Canadian). Following upon the early successes, the industry subsequently expanded into Nova Scotian waters, particularly the Annapolis Basin, and also into Cobscook Bay and other areas of northern Maine. The southernmost finfish farms at present are in Blue Hill Bay, just south of Mt. Desert Island. Maine (Churchill 1997). The great majority of the sites are located in the protected waters of Passamaquoddy Bay, L'etang Inlet and Cobscook Bay, and in the lee of nearby coastal islands. With most of the suitable inshore sites occupied, and facing conflicts with traditional fisheries and rising environmental concerns (Milewski et al. 1997) there is some interest in the possibility of expanding the industry to larger offshore sites (Harvey in press). Research is also ongoing into the possibility of farming other marine species such as halibut and haddock (Waiwood et al. 1994).
Unlike finfish aquaculture, which is largely confined to the well-mixed areas of the northern Gulf where winter water temperatures are slightly higher, various species of shellfish are being farmed at sites along much of the coast of the Gulf. Only the silt-laden waters at the head of the Bay of Fundy appear to be unsuitable. Species in culture include American and European oysters, mussels, sea scallops and clams in northerly areas. Clam and sea scallop aquaculture is a rapidly growing industry in Cape Cod Bay (Shelley in press). In some areas sea urchins are also held in cages for extended periods until ready for market. Shellfish aquaculture involves restraining or confining the animals but allowing them to feed passively upon natural particulate material in the water. To date there have been few reports of adverse environmental effects from this type of operation.
In contrast, Salmon farming involves confining large numbers of fish in a small area and feeding them intensively with processed food. As a result a large quantity of particulate and dissolved organic waste, comprising uneaten food and feces is continually released in a small area over an extended period. The nature and quantities of the wastes generated by fish farms of various sizes and types have been well documented (see references in Wildish et al. 1993). There is growing concern about the potentially adverse impacts of these wastes on coastal marine habitats and communities (Milewski et al. 1997), and some of these are addressed more fully in section 5.8.
intertidal harvesting
In many areas of the Gulf a variety of marine species are harvested from the intertidal zone. These include, clams and baitworms on mudflats, and mussels, periwinkles, dulse, irish moss and rockweed on rocky shores. There are growing concerns about the potential impacts of local overexploitation on both the resource species themselves as well as on the intertidal communities and habitats that sustain them (Rangeley 1994), particularly as harvests of many of the so-called underutilized species have been expanding rapidly in recent decades as traditional fisheries resources have declined.
Clams, mussels and marine worms have long been commercially important in various parts of the Gulf. It is estimated that in Maine alone the annual value of the fishery for these three species is $13-$15 million (US) (Harvey et al. 1995). Clam, Mya arenaria, digging on intertidal mudflats is unquestionably the most economically important of these activities. The mudflats also yield an abundance of polychaete worms, particularly the bloodworm, Glycera dibranchiata, that are commercially harvested for use as bait in recreational fishing (Klawe and Dickie 1957; Creaser et al. 1983). In recent decades, baitworm populations along much of the eastern seaboard of the U.S. have been greatly reduced by overexploitation and, as a result, much of the harvesting pressure has shifted to the extensive mudflats of the upper Bay of Fundy.
Both clam and baitworm harvesting involve digging up and overturning large volumes of sediment. There is a growing concern about the potential effects of this continuing disturbance of large areas of substrate on the mudflat community as well as upon the stability and integrity of the mudflats themselves. Mudflats are dynamic structures, and studies by Amos and his colleagues (see Daborn 1997 and Greenberg et al. 1997, for overviews) have shown how sensitive the balance between erosional and depositional processes is to a variety of biological and physical factors. At present we know little about the impacts of such repeated human disturbance of large areas of sediment habitat.
On rocky shores, hand harvesting of species of seaweeds such as irish moss, dulse and rockweed has also been carried out for generations, to provide food, fertilizer, soil conditioner or mulch. However, large-scale commercial harvesting of rockweed for fertilizer and alginate extraction has occurred over the past three decades, primarily in Digby and Yarmouth counties of Nova Scotia (Gordon 1994a). Initial seasonal, part-time hand cutting and raking by fishermen were soon replaced by the use of large mechanical harvesters equipped with a vacuum device and cutter blades that could collect far larger quantities of rockweed. The new harvesting technology dramatically increased the harvest in SW Nova Scotia from about 5000 T in 1985 to 27,000 T in 1988 (Sharp and Tremblay 1989) and resulted in the removal 40-80% of the rockweed biomass in harvested areas (Rangeley 1994). There were soon indications that the beds were being overexploited. Since 1990 the harvest has largely reverted to hand cutting and raking (Sharp et al. 1994), and mechanical harvesting has been prohibited in eastern Canada for several years (Glyn Sharp pers. comm.). Increasing pressures by processing companies to further expand the harvest has resulted in the launch of a three year pilot project in the waters of southeastern New Brunswick to collect 10,000 tons of rockweed. Whether the industry will be permitted to expand further in New Brunswick is at present uncertain. In Maine rockweed harvesting has occurred on a much smaller scale, largely for agricultural use and for packing live lobsters (Wippelhauser 1996). However, if the industry is successfully developed in New Brunswick, and if market conditions improve further, then it is likely that there will be considerable pressure to expand the harvest in Maine. There are concerns among scientists and environmental groups that by harvesting rockweed we are, in effect, harvesting important marine habitat. It is increasingly being recognized that rockweed beds are critically important as foraging and refuge areas for a wide variety of marine species, including several commercial fish species. The important ecological roles of rockweed in the coastal ecosystem and the potential consequences of harvesting it are described more fully in section 5.6.
Periwinkles too have long been sustainably harvested by hand for local consumption in many parts of the Gulf. In the Maritimes in recent years the pace of harvesting has increased dramatically with the introduction of suction harvesting techniques. These dredges not only vacuum up most of the periwinkle standing stock in an area, including all size classes, but also take many other intertidal species as well. There are concerns that there may be overexploitation of the resource (Kearney 1994) as well as considerable habitat damage.
subtidal harvesting
The use of heavy trawl gear, and in particular its threat to the integrity and productivity of benthic habitats, has been identified as a problem throughout the Gulf of Maine (Dow and Braasch 1996). National Marine Fisheries Service data reveals that the intensity of such trawling activity has risen sharply in recent decades (NEFSC 1995). It has even been suggested that virtually all seafloor areas of the Gulf are being subjected to some degree of perturbation by heavy fishing gear almost every year (Auster et al. 1995). Some of the potential ecological implications of these activities are discussed in Langton (1994). Although the use of mobile fishing gear is not included in the GPA list of land-based activities, arbitrary exclusion from this report seems inappropriate given growing public concerns about the potential damage being done, particularly to nearshore benthic habitats. It is difficult to argue that such inshore fisheries are not land-based. In coastal areas and estuaries along the entire coast heavy gear has long been used, and is still being used, to harvest groundfish, scallops, urchins and mussels (Shelley in press). For example, in the St. Croix Estuary located on the U.S. - Canada border, each year up to 10 Canadian and 60 American fishing boats drag the area for scallops (Harvey in press). Similar intense fishing pressures are reported in almost every estuary and embayment around the Gulf (Shelley in press). In parts of northern Maine dredging for sea cucumbers is a growing industry. These activities all involve dragging heavy trawls or dredges repeatedly over extensive areas of the sea floor in relatively shallow waters. In some areas the disturbance continues year round as different species are harvested in turn. The repeated passage of such heavy gear tends to level out bottom irregularities and uproot macroalgae and eelgrass. This tends to reduce the structural complexity of the benthic habitat, which could in turn reduce overall biodiversity as specific microhabitats and protective refuges are eliminated. Trawling and dredging also resuspends sediments into the water column, temporarily increasing turbidity and enhancing deposition on nearby habitats. Although the potential for substantial habitat degradation appears great (McAllister and Spiller 1994), the research carried out thus far has not provided definitive answers (Langton 1994; Jones 1992). There is a critical need for more detailed information about large and small scale effects of trawling and dredging (Dow and Braasch 1996).
aggregate extraction
Quarrying in coastal regions, and aggregate extraction in intertidal zones or offshore areas, are raising concerns about potential effects of the activities on marine habitats in the vicinity. The likely environmental effects of coastal quarries, such as the proposed granite quarry on the shoreline of the St. Croix Estuary (Harvey in press), are at present poorly understood. All around the Gulf, large amounts of sand, gravel and cobble (collectively termed aggregate) are used each year for road construction, building, and other industrial purposes. Up to now, most of this has come from terrestrial sources. Over the past century substantial volumes of aggregate were also extracted from accessible intertidal deposits in various places. The impacts of these activities on beach and subtidal habitats were generally not monitored, but must have been substantial. In all jurisdictions such removal of beach material has been prohibited or carefully regulated for decades (e.g. the Beach Preservation and Protection Act, enacted in Nova Scotia in 1975).
However, convenient terrestrial sources of aggregate are rapidly being depleted and new quarries face increasing public opposition and tougher environmental standards. As a result there is growing interest in the possibility of mining aggregate from submarine sources. In several places around the Gulf promising submarine deposits have already been identified and mapped, such as in Massachusetts Bay (Duane et al. 1988) and Scotts Bay in the Bay of Fundy (Greenberg et al. 1997). Many other deposits around the Gulf are too small or too deep to be mined economically at present. Although aggregate extraction from submarine deposits has not yet been undertaken on a commercial scale in the Gulf, successful operations in Europe and Japan have demonstrated the technical and economic feasibility. The aggregate is usually recovered with a trailer suction dredge. A vessel, equipped with a high capacity pump and a large diameter pipe ending in a large dredge head, moves slowly forward while sucking up bottom deposits. The material is washed through screens to remove mud and the sand and gravel dumped into the hold. When the ship is dredging , a large plume of silt is released. As the ship criss-crosses an area it excavates trenches in the seafloor, up to a half a meter deep and two meters wide. With continued dredging the entire seafloor can be lowered significantly over a large area.
Studies carried out elsewhere suggest that there are a variety of potentially significant environmental impacts that may accompany suction mining of submarine deposits (Day 1994). Seabed mining and navigational dredging (see section 4.2) use similar methods and have similar potential environmental impacts, differing primarily in intent and location. Pearce (1994) reviewed the available literature on both these activities pertaining specifically to the Gulf of Maine region. The principal environmental concerns include direct destruction of bottom habitat and communities, enhancement of coastal erosion and the generation of dense sediment plumes that could conceivably adversely affect primary production, zooplankton, ichthyoplankton, fish and marine mammal populations.
fossil fuel/nuclear plants
Electrical generating stations are common on many of the larger rivers flowing into the Gulf of Maine as well as at many locations around the coast (Dow and Braasch 1996). Habitat impacts of hydroelectric generating plants situated on rivers are considered in section 4.3 that deals with dams, as it is largely the impoundment of water that leads to habitat modification, although turbine operations do kill fish. The fossil-fuel and nuclear power plants are primarily situated in coastal areas in order to be close to the centers of power demand as well as to sources of water for cooling purposes. While there are various contaminant issues pertaining to both types of power plants (Eaton et al. 1994), it is the release of heated water that may physically alter habitats, and is thus of particular interest here. The heated water released from these plants may form plumes that are as much as 10-15 degrees warmer than the ambient water temperature (Vadas et al. 1976; Kennish 1992). Some of the potentially adverse effects of such thermal plumes on the marine ecosystem are well described in Fefer et al. (1980). The warmed water has been shown to adversely affect rockweed beds near the outfalls (Vadas et al. 1976) and it also alters the thermal characteristics of local benthic and water column habitats. This could influence the use of these habitats as migration, spawning or nursery areas by fish and invertebrates (Eaton et al. 1994). In most cases dispersion of the heated water is relatively rapid and thermal affects are largely confined to within a few hundred meters from the point of discharge. The few studies that have been conducted in the region suggest no major, widespread impacts from the discharges (Eaton et al. 1994).
tidal power
The causeway across the Annapolis River Estuary in Nova Scotia was originally constructed to protect upstream dikelands from the tidal flooding. In 1984 the structure also assumed a new role as the site for the first operational tidal power generating station in North America. Engineers had long dreamed of harnessing Fundy's surging tides, but it wasn't until the late 1970's, in the wake of rapidly rising crude oil prices, that a major program of economic, engineering and ecological studies was undertaken to assess the feasibility of a proposal for a massive tidal power project somewhere in the Bay. The potential ecological impacts of the proposal were examined in considerable detail in a suite of studies summarized in a variety of publications (Daborn 1987; Gordon and Dadswell 1984; Gordon 1994b), while some of the potential repercussions for the broader Gulf of Maine region are discussed in Campbell (1986) and Greenberg (1984). It is possible that there could be "major unforeseen consequences" for the whole Gulf ecosystem (Kelley and Kelley 1995). Although the full-scale tidal power project was eventually shelved, the 20 megawatt Annapolis facility was eventually constructed as a pilot-scale prototype to evaluate engineering design and environmental impacts.
Passage through the turbines kills a significant proportion of many species of anadromous fish whose populations are already stressed by other factors (Stokesbury and Dadswell 1991). However, the impacts on riverine, estuarine and marine habitats have been more subtle and difficult to discern. Indications are that sediment dynamics, and benthic and mudflat habitats, have been altered both in the river and in the estuary, although it has not been possible to discriminate between the effects of the tidal power plant installation from those of the earlier causeway construction. It has been suggested that an even larger scale Fundy tidal power installation could affect coastal currents, patterns of primary productivity, flushing rates in estuaries, distribution and settling patterns of larval fish and shellfish and the location and magnitude of oceanographic fronts over extensive areas of the Gulf (Kelley and Kelley 1995).
The shorelines and coastal waters of the Gulf offer a wealth of recreational opportunities to the 3.6 million residents of the region. Many millions more visit the coastal area each year to enjoy many of these same activities and amenities (Stevenson and Braasch 1994). Much of the shoreline development in many areas has been a direct result of the steadily increasing growth in tourism. In certain areas, seasonal increases are dramatic; for instance, in Maine, its 4.25 million annual visitors quadruple the states population. Since 95% of these visit the coast, this results in a transient visitation that is seven times the resident population of the coastal counties (Colgan 1989). The same author points out that statistics on tourist populations are questionable as much of the information is either not collected, intentionally withheld or combined with other factors. One of his recommendations to the Gulf of Maine Council was for the systematic compilation of these statistics.
Tourism is the fastest growing business everywhere, and it is predicted that within a few years tourism will be the number one industry world wide. Tourism is more than a business consideration, as it fundamentally alters the natural environment and the social order. It has been shown in other regions that the tourist industry can be a valuable proponent for healthy coastal environments (McNeely and Thorsell 1988; OECD 1980). However, the use of natural resources for outdoor recreation, and tourism can produce conflicts with conservation and protection efforts (Kenchington 1990). Coastal environments can be stressed by tourism and its extensive infrastructure and as well, tourism can be constrained by conservation concerns. Concepts such as carrying capacity are of limited value unless the scientific and cultural issues are addressed (Stankey and McCool 1990).
Coastal islands are particularly attractive to tourists as well as to inhabitants of nearby urban centers interested in a second seasonal residence. On the islands of the Outer Banks of North Carolina, from 1980 to 1990 there was a 100% increase in building permits. The most significant problem was the need for groundwater to sustain growth, which was in direct conflict with the maintenance of wetland quality. Septic contamination of the groundwater and the mining of barrier dunes for fill were other significant conflicts (Miller and Auyong 1990). At Swan's Island ME, the addition of 15 - 20 wells a year caused salt water seepage and a concern for wetland "recharge areas" and on Monhegan Island the aquifer that supplies the 450 residents runs out in a dry summer. Coastal and island communities, whose economies are largely sustained by tourism and seasonal residency, are strongly opposed to initiatives that seek to limit or control tourist numbers.
Sandy beach habitats and the associated dune systems are also particularly vulnerable to developmental pressures as well as to the associated recreational activities. The high economic value of beach-front property and beaches has largely fueled the continuing beach protection and replenishment programs designed to combat erosion. Intense recreational use of many beaches, such as Wells Beach in Maine, may be jeopardizing their use as critical nesting habitat for some seabirds and shorebirds (Shelley in press).
The rapid growth in recreational boating in many areas has had significant consequences for coastal habitats in many areas. The demand for marinas and mooring sites, particularly from central Maine southward has risen dramatically in recent decades. For example, in the Great Bay Estuary of New Hampshire the number of mooring permits increased 5-fold between about 1975 and 1990 (Shelley in press), and the demand continues to rise. Unfortunately, the most desirable marina sites are usually in protected areas of estuaries and sheltered inlets, which are also prime eelgrass and salt marsh habitats. Construction and dredging for marinas and moorings in areas such as Casco Bay has damaged eelgrass beds, while anchoring can also uproot plants and disturb the sediments (Shelley in press). In addition, the propellers of boats maneuvering in shallow waters cut and uproot the plants and resuspend sediments. The turbulent wash from the rapidly proliferating shallow draft power boats, particularly jet skis, are causing erosion of river banks and salt marshes in many estuaries such as the Annisquam River in Massachusetts (Shelley in press). Meanwhile, on the shore, off road vehicles and recreational ATVs are frequently driven over barrier beaches and dunes, destroying vegetation and triggering erosion. This is affecting not only the larger beach/dune systems of Cape Cod but is also a problem on smaller ones such as Mavillette Beach in Nova Scotia.
4.7. Confounding factors and intermediary processes
The processes involved in the destruction or degradation of coastal habitats as a result of human activities discussed above are often subtle and complex. All around are habitats clearly being degraded, but in only rare instances is it possible to confidently point to a "smoking gun" responsible for all the damage. In a very few instances, such as the burying of a saltmarsh with fill, or the dredging of an eelgrass bed, the linkage between cause and effect are readily identifiable and unequivocal. More often, there are a series of complex intermediary processes leading up to the degradation of habitat, and these are typically insidious, gradual and poorly understood. In most situations a variety of confounding factors, such as natural ecosystem cycles or cumulative effects, are also at play and often obscure cause and effect relationships.
Confounding factors
Perhaps the most difficult factors to account for are the natural variations that occur in any ecosystem, because an adequate understanding of their effects inevitably requires intensive, long-term studies of the components of the ecosystem of particular interest. Some of these ecological changes are unpredictable, at least on the basis of our current knowledge, and include things like sudden population explosions of particularly influential species or the sudden outbreak of diseases. For example, the effects of rapid increases and abrupt decreases in sea urchin populations on the stability of the kelp bed habitat in the Gulf is described in section 5.11, while the dramatic impacts of wasting disease on eelgrass meadows, and on the biota that depend on them, is discussed in section 5.10.
Many of the ecosystem changes are cyclic in nature, often linked to solar or lunar periodicity. An example is the 18.6 year cycle in tidal amplitude (nodal cycle) associated with variations in the declination of the moons orbit (Greenberg 1983). There are indications that the nodal cycle may be associated with variations in ocean currents, vertical mixing and water temperature (Loder and Garrett 1978), which in turn may influence ecological processes and populations of marine organisms inhabiting the pelagic zone (Cabilio et al. 1987). The exact nature of the links in this complex chain of events are only poorly understood.
Other ecosystem changes, such as sea level rise, are progressive in nature, at least from our limited time perspective. The Gulf is relatively young as an oceanographic and ecological entity, released from the grip of great glaciers little more than 13,000 years ago (Kelley et al. 1995). Early on, the bounding banks rose above sea level, making the Gulf an almost enclosed shallow estuarine basin draining into the Atlantic. Rising sea level has submerged the offshore barriers and allowed the sea to encroach up river valleys and expose new areas of shoreline to the forces of erosion. Gradual crustal subsidence in the region has caused sea level to slowly rise over the past 7,000 years and it is now estimated to be rising at a rate of about 13-21 cm each century (Scott and Greenberg 1983), exacerbated to an as yet unknown degree by melting of polar ice caps as a result of global warming. Some of the possible impacts of such sea level changes on production and on coastal habitats in the Bay of Fundy - Gulf of Maine region are described in Gordon (1986). Almost all coastal habitats are probably undergoing some changes associated with rising sea level and increasing tidal amplitude, although the exact nature of these responses are not well understood at present.
Interpretation of the underlying causes of habitat changes is further complicated by the fact that many different human activities are contributing to the environmental problem simultaneously. This may reflect the inputs from many different sources of a single ecological stressor. For example, mudflats and salt marshes are vulnerable to any activities that alter sediment dynamics in the watershed or coastal zone. It is well known that agriculture, forestry, road construction, urban development, coastal armoring, dam construction, dredging and many other human activities can all result in modifications to patterns of sediment erosion, transport and deposition and thus to the alteration of habitats dependent on sedimentary processes. In many areas habitat changes probably reflect the combined results of many different ecological stresses acting simultaneously, the so called cumulative effects. For example, an eelgrass bed may be being systematically degraded by a combination of boating activity, nearby dredging, excessive nutrient loading and coastal infilling. Occasionally the impacts of these combined stresses can be far greater than would be expected from simply adding the effects of the individual stresses, the so called synergistic effect. Most often, a degrading habitat reflects the combined influences of cyclical processes, progressive environmental changes and multiple human activities all working together.
Perhaps the biggest obstacle to attempts to link habitat degradation to specific causes is the general inadequacy of our present understanding of many of the complex physical, chemical and ecological processes involved. Typically, our level of understanding and predictive capabilities decline rapidly with increasing spatial and temporal scales, and usually it is the impacts over wide areas and over the longer-term that are the greatest threat to overall habitat integrity and ecosystem health. For example, there have been many studies done on the impacts of finfish aquaculture pens on the benthic habitat immediately below them, and a number of useful models have been developed to describe the process. Although there are varying degrees of localized habitat degradation (see sections 4.4 and 5.8) there appears to an acceptance in some quarters that the impacted areas are small and the overall ecological consequences are thus acceptable. However, we know very little about the transport of the so called mariculture sludge away from the cage sites, where else and how it might accumulate and what the ecological impacts of this accumulation might be. There are concerns that broad areas of intertidal and subtidal habitat could be degraded over the long-term by aquaculture wastes accumulating faster than they can be assimilated by the system. Similarly, although progress is being made in understanding some of the processes that effect sediment dynamics over small areas in the short-term (see section 5.3), many of the longer-term processes involving large geographic areas still elude us, even though these may be the most worrisome with respect to significant habitat degradation. For example, some scientists suspect that some of the adverse changes now being seen in many mudflat habitats in the upper Bay of Fundy may be the long-delayed, or slowly building, effects of alterations in sediment dynamics that were triggered by the damming of major rivers in the region over three decades ago (Brylinsky et al. 1997).
Intermediary processes
There are often a number of intermediary processes intervening between the actual land-based activity and the ultimate impact on a marine habitat. Mostly these are complex and poorly understood, leading to further difficulties in linking anthropogenic causes and ecological effects. Often too, several human activities feed into the same intermediary processes and several different habitats may experience the brunt of their impacts, adding yet more variables to an already complex situation. Although there are several of these intermediary processes that could be described, perhaps the most important from the present perspective are eutrophication, sediment dynamics and hydrology.
Eutrophication
The term"eutrophic" literally means much feeding and is most commonly applied to aquatic ecosystems exhibiting high levels of primary productivity. Although eutrophic systems can, and often do, support high levels of secondary production, they are usually characterized by conditions that lead to a reduction in secondary production, particularly of benthos, resulting from the accumulation of substances such as hydrogen sulfide, ammonia, methane and other toxic gases. This occurs when the system becomes hypoxic or anoxic as a result of the depletion of dissolved oxygen brought about by the decomposition of organic matter originating from excessive algal growth.
Although some aquatic ecosystems are naturally eutrophic, many have become eutrophic as a result of the activities of humans, a process referred to as "cultural eutrophication". Cultural eutrophication results from increased levels of nutrient inputs, primarily phosphorus and nitrogen, to a system. The most common sources of nutrient leading to eutrophication are inputs from sewage and run off of fertilizers from agricultural and urban lands. In some cases aquaculture operations, particularly for finfish, can lead to localized areas of eutrophic conditions. Eutrophication has become a serious problem in many estuarine and coastal systems since this is where many of the waste products of humans are ultimately deposited. The process of eutrophication can have negative impacts on commercial fisheries, recreation and public health (NOAA 1992).
Sediment dynamics
Another important intermediary factor that often complicates the linkages between land-based activities and habitat impacts is sediment dynamics. The structure and function of many coastal habitats may be markedly influenced by alterations in the processes associated with sediment erosion, transport and deposition. In fact, according to Daborn (1991), in the upper Bay of Fundy in particular, it is the dynamics of the sediments that are the key to understanding the functioning of its ecosystems. This is probably true to a lesser degree for many of the coastal habitats around the Gulf of Maine. As we have seen, a great many land-based activities can influence sediment dynamics. Considerable progress is being made in understanding and modeling some of these sediment related processes (see Daborn 1997 and Greenberg et al. 1997 for overviews). The development of the concepts of a dynamic balance between sediments and water and of an "equilibrium capacity" (Amos 1995) has been particularly useful in understanding the effects of human modifications to estuaries (Daborn 1997). Thus water bearing less than its "equilibrium capacity" of sediment will tend to mobilize sediments from nearby shorelines, while water with more than this will tend to deposit sediments in areas that will accommodate them. Similarly, a multidisciplinary project involving over 30 scientists from 5 nations, the Littoral Investigation of sediment Properties (LISP) is providing a better understanding of the behavior of fine sediments in coastal waters and aiding in the development of improved sediment dynamics models (Daborn 1991). In spite of these and other recent advances in knowledge it is still difficult if not impossible to predict the impacts of many land-based activities on sedimentary processes, particularly over larger areas and in the longer term. Further discussions of specific sediment issues are included in the sections 5.3 and 5.10.
Hydrological processes
Closely linked to the question of sediment dynamics is another important intermediary factor, namely hydrological processes. Most sediments are mobilized and transported by water, so anything that influences the volumes or patterns of water flow or the velocity or direction of currents will also have a profound effect on sediment dynamics. In addition, altering the patterns of water flow in rivers by the construction of dams can significantly change a range of other factors such as water temperature, salinity, nutrient loading and mixing in the estuaries into which they flow, and in nearby coastal areas. As we have seen many of the land-based activities described above have some influence on water flow characteristics and thus the potential to alter habitats. Often, many different activities in a watershed influence hydrodynamic processes in nearby rivers, estuaries and coastal areas in a complex cumulative or synergistic manner. Many of these hydrologic processes are poorly understood, making it difficult to predict effects on coastal habitats. A few of the more important of these hydrologic issues are dealt with in sections 4.3 , 5.2 and 5.3.
The Gulf of Maine is a well defined and ecologically distinctive (Conkling 1995) embayment encompassing some 90,700 km2 (Stevenson and Braasch 1994) of the continental shelf of eastern North America. Extending from 41o N to 46o N and longitudinally from 65o E to 71o E, it is bordered by a 5,600 km coastline involving the states of Massachusetts, New Hampshire and Maine and the provinces of New Brunswick and Nova Scotia. Its 90,700 km2 watershed drains substantial proportions (36 -100%) of each of these territories as well as a small area of southern Quebec (GOMCME 1992). It is a shelf sea with an average depth of 150 m and a maximum depth of 377 m (Kelley et al. 1995). It includes three large basins that exceed 250 m (Townsend 1996) and is bounded to seaward by four large banks less than 60 m deep (Lynch 1996). These reduce the influence of the adjacent Northwest Atlantic Ocean, creating a relatively enclosed oceanographic system, with a well defined internal circulation pattern, that can be considered a distinctive ecological entity. However, the oceanographic isolation is not complete, because three major channels connect the Gulf with the Atlantic (Lynch 1996). The northernmost of these is the main entry for Atlantic water from the Scotian Shelf, while the deeper Northeast Channel between Browns and Georges banks permits the only inflow of nutrient-rich slope water (Kelley et al. 1995). The Great South Channel southeast of Cape Cod is the main outflow from the Gulf onto the adjacent continental shelf (Yentsch et al. 1995).
The coastline of the Gulf is complex and varied. This can largely be attributed to the eight distinctive geological regions along the coast (Kelley et al. 1995), characterized by rocks of differing origin, composition, orientation and resistance to erosion. Thus, there are the readily erodible sandstones and shales that surround the upper Bay of Fundy, the stark resistant bedrock headlands that characterize much of the Maine coast and the southernmost area towards Cape Cod that is completely lacking in bedrock and comprised largely of glacial deposits of sand and gravel (Kelley et al. 1995), and other more subtle geological distinctions elsewhere. The variability in oceanographic conditions and in the coastal and submarine geology and topography results in a great diversity of habitats within the Gulf of Maine.
This report adopts a rather general definition of the term habitat. Typically habitat is defined from the perspective of a species and its preferred portion of the environment. However, for any given species this encompasses many different parts of the environment that can vary with age, life history stage, season or even time of day. Typically it include spawning grounds, nursery areas, feeding zones and migration routes (Gordon 1989). In this context, identification and ranking of important habitats requires a judgment about the relative value of different species. This is the approach being taken by the US Fish and Wildlife Service and the Gulf of Maine Council in the Gulf of Maine project, where some 161 species of marine plants and animals have been ranked according to a suite of up to 10 ecological, economic or conservation criteria (USFWS/GOMCME 1994). The intent is that this ranked array "can be used as a focus for identifying habitats".
The definition of habitat of Ryder and Kerr (1989) that views habitat as a structural component of the environment that serves as a centre of biological activity is more manageable and suited to present purposes. This approach was used by the Maine Department of Conservation in its classification of ecosystems and natural communities (Gawler 1991), although the marine and estuarine benthic areas alone were subdivided into 67 distinct habitats according to a variety of topographic, geological, physical and chemical factors (Brown 1993). This scoping paper considers only 12 very broad habitat categories; namely, saltmarsh, mudflat, sand beach/dune, cobble beach, rockweed bed, coastal islands, inshore (subtidal) benthic, inshore pelagic, eelgrass beds, kelp beds, offshore benthic and offshore pelagic. The term "pelagic" is used in the sense of Vernberg and Vernberg (1970) to refer to the water column itself, with the inshore pelagic extending from the low tide line to an arbitrary depth of about 50 m, and the offshore pelagic comprising everything deeper. The selected habitats differ considerably in primary productivity as shown in Figure 1.

An estuary is not a habitat as such, but rather a of grouping of several interdependent habitats existing in close proximity. These individual habitats, which are not necessarily restricted to estuaries, are dealt with in the sections that follow. Nevertheless, estuaries are important ecological units that are widely distributed around the Gulf of Maine, and many research programs and conservation activities are focused on estuaries as a whole rather than on the component habitats. This brief overview is included to present some of the habitat issues in an estuarine context.
Estuaries are coastal ecosystems where freshwater flowing from inland rivers meets and mixes with seawater. They are considered to be one of the most productive aquatic ecosystems in the world and are particularly noted as important nursery grounds for many commercially and recreationally important species, including both finfish and shellfish. They are important staging areas for waterfowl and shorebirds. The high biological productivity typical of most estuaries is due largely to the unique hydrodynamics that results when freshwater and sea water mix. A complex set of factors interacts to create a system that concentrates both inorganic and organic nutrients as well as planktonic organisms. In addition, nutrients tend to be recycled rapidly as a result of both physical and biological processes.
The biological communities present in most estuaries are typically characterized as having high biomass but low diversity, the latter being the result of the stress imposed by the high spatial and temporal variations in salinity which make it a difficult environment for organism that have little ability to osmoregulate. The pelagic community of Gulf of Maine estuaries is dominated by an assemblage of diatoms, flagellates, copepods and meroplanktonic larvae. The benthic subtidal community consists mainly of various polychaetes, mollusks and crustaceans, many of which are important food items of commercially and recreationally valuable species. Salt marshes, mudflats and seagrass meadows are other important habitats that are common in many estuaries and are described in more detail in the following sections.
Estuaries are particularly vulnerable to eutrophication, since the nutrient load from diverse terrestrial sources is mostly riverborne. The ability of an estuary to absorb nutrients before becoming eutrophic depends on a number of complex factors. The most important is its flushing characteristics which largely determines how long nutrients will be retained in the estuary and, in the case of those algal species that grow within the water column, the amount of algal growth that will be exported from the estuary to the sea. The flushing characteristics of an estuary also determine the degree to which the estuary becomes anoxic and accumulates toxic by-products resulting from decomposition of organic matter. In general, the more highly flushed an estuary, the less susceptible it will be to eutrophication and deterioration of water quality. The degree to which an estuary is flushed depends largely the relative magnitudes of estuarine volume, river flow volumes and tidal amplitude volume., the larger the river and tidal volume relative to the estuarine volume, the greater the degree of flushing.
Because the estuaries around the Gulf of Maine, particularly those located in the more northern areas, are subject to relatively high tidal flushing, they have relatively high assimilative capacities with respect to nutrient loading. In addition, most are located in areas away from the larger industrial/urban centers along the east coast of North America. Accordingly, eutrophication problems do not exist to the same degree as they due in estuaries located further south having lower tidal amplitudes and a larger degree of urbanization.
The status of estuaries along the United States Gulf of Maine coast has recently been evaluated by the Office of Ocean Resources Conservation and Assessment (ORCA) of the National Oceanic and Atmospheric Administration (NOAA) as part of the Estuarine Eutrophication Survey of the National Estuarine Inventory (NOAA 1997). A total of 18 estuaries were evaluated, seven in the southern Gulf of Maine (Cape Cod Bay to Great Bay) and eleven in the northern Gulf (Saco Bay to Cobscook Bay). Of the estuaries surveyed, four were reported to periodically exhibit high chlorophyll levels, two high nitrogen concentrations, none high phosphorus concentrations and five occasional periods of hypoxia or anoxia. In the case of the latter, anoxic conditions occurred in only one estuary on an episodic basis and included the entire water column. Biologically stressful levels of dissolved oxygen, however, were reported in all or a portion of nine estuaries and occur on a periodic basis, usually between July and September.
The information available on changes in community structure is limited but that available indicates relatively little change over time (1970-1995). Changes in the level of primary productivity and composition of the plankton and benthic communities were reported in only two estuaries. Although submersed aquatic vegetation were reported present in 15 estuaries, the spatial coverage in all cases was low. Temporal information was available for only 7 of the 18 estuaries surveyed. A decrease in submersed aquatic vegetation was reported for five and an increase reported in two estuaries.
The Canadian estuaries have not been studied to the same extent as those of the US. A recent survey has been carried out by the Conservation Council of New Brunswick (Harvey in press). This study, part of the Gulf of Maine Estuaries Restoration Project, compiled information available on 12 Bay of Fundy estuaries. There is little indication that any of these estuaries have serious eutrophication problems. This is in part due to the very high flushing rates, particularly in the more northern areas where tidal amplitudes are often greater than 10 meters, and in part to the relatively small degree of urbanization and industrialization within the watershed of most estuaries. There do, however appear to be some localized eutrophication problems in areas of extensive finfish aquaculture operations, particularly in the LEtang estuary.
habitat characteristics
Salt marshes are an important feature of many estuaries and relatively sheltered, low energy, coastal locations in temperate latitudes. They commonly develop on stable or emerging shorelines, but can also be found on submerging coasts if the rate of sediment supply is greater than the rate at which the land is sinking or local sea level is rising. They are highly dynamic systems, responding to the interactions between fresh water, sea water and sediments, growing and receding as these forces change over time. This dynamic response occurs through the growth of the dominant species of vegetation, but is critically influenced by sediment supply, wave action, and human activities. Remnants of once extensive salt marshes are present in various parts of the Gulf, particularly on Cape Cod, along the northern Massachusetts coast, bordering Maines extensive and numerous estuaries and in the Bay of Fundy, near its mouth and particularly along the margins of Chignecto Bay and Minas Basin (Gordon 1994a). It has been estimated that there are only about 158 square kilometers of salt marsh remaining in the Gulf of Maine region, with two thirds in the United States and one third in Canada (Jacobson et al. 1987).
In the Bay of Fundy, salt marshes developed most extensively in the inner portions of the system, in Minas Basin, Cumberland Basin and Shepody Bay, and in the Annapolis Basin. Smaller marshes are present in many estuarine locations around the Bay. Typically, the lowest point of a marsh corresponds to the mean high water mark of neap tides , below this the intertidal zone is a mud or sand flat, which is covered by water at least half of the time during any tidal cycle. The area of marsh below mean high water that is flooded regularly is characterized as low marsh. The uppermost level of the marsh (high marsh) extends above the high water spring tide level, where it may be flooded on only a few tides each year. Although the difference in elevation between the upper and lowermost parts of the marsh may be small, variations in flooding depth and frequency, in the influence of fresh water, and in the amount of sediment carried by flood waters, leads to a more or less distinct zonation of different plants.
The marshes are dominated by species of Spartina: S. alterniflora (marsh or smooth cordgrass) at the lower levels, and S. patens (marsh hay) at the upper end. These dominants are interspersed with other plants, notably Distichlis sp. and Juncus sp. (Black grass), Sea lavender (Limonium sp.), plantain (Plantago sp.) and glasswort (Salicornia sp.). Cordgrass is the initial colonizer, establishing itself on new deposits of sediment when these accumulate to the neap tide high water level. They develop extensive root systems that stabilize the sediment, and trap more sediment each time the tide floods the marsh. Much of the new sediment is deposited at the edges of tidal creeks, building up levees upon which the S. alterniflora grows relatively tall. Behind these channel edges the marsh surface is lower, a shorter form of cordgrass occurs. Because of the levees, the marsh is often flooded less regularly, and may contain ponds that harbor a wide variety of invertebrates and some fish. At higher elevations, cordgrass gives way to marsh hay, so-called because it was harvested for cattle feed in earlier times. The marsh and its ponds harbor a limited diversity of animals (e.g., mud snails, polychaetes and some insects), but these are sometimes very numerous, providing a substantial food source for fish (e.g., Atlantic silverside, killifish, mummichog, and three-spined stickleback), and for resident and migratory birds (e.g., swallows, herons, godwits).
Winter ice conditions make the Fundy marshes very different from those further south. Ice 'plucking' during winter can remove much of the above-ground S. alterniflora, adding to the detritus chain. The two Spartina species also exhibit different growth patterns in summer : according to research carried out in Minas Basin, S. alterniflora loses leaves on a regular basis as it grows during the summer, whereas the previous years' above ground growth remains beneath the marsh hay (S. patens), decaying only slowly. Very little of the marsh production is consumed by animals while it is alive, but Spartina detritus is a major contributor to food chains after the leaves have died. The salt marshes of New England differ from those of Fundy in a number of other characteristics, particularly in their much higher organic content (Nixon 1982). They have largely developed on layers of marine peat behind barrier beaches or in river mouths, while those of the upper Fundy region lay upon thick deposits of marine silt (Gordon 1986). The Fundy salt marshes are not quite as productive as those further south. Their role in stabilizing intertidal sediments, providing feeding and spawning habitat for some fish and birds, and contributing to the food chains of adjacent waters was probably of greater significance prior to European settlement (Gordon 1986). The remnant salt marshes that rim much of the Gulf still fulfill many important ecological roles and their structural and functional components are schematically presented in Burdick et al. (1994). Their role in contributing organic matter to other coastal habitats is detailed in Gordon et al. (1985) and Gordon and Cranford (1994).
habitat issues
Coastal salt marshes were once a much more important natural feature of the Bay of Fundy, covering an estimated 28,000 ha. Since the settlement of Europeans, however, these marshes have been extensively diked and converted for agricultural use, leaving only about 6,500 ha (23%) still 'out to sea'. In a number of places, modifications to water flow have caused relatively large salt marshes to develop anew (e.g., as a result of building dams at Windsor, N.S. and Moncton, N.B., and along the seaward side of dikes that are still maintained). In other cases, restrictions of water flow onto marshes resulting from the building of culverts beneath roads have converted marshes that were previously net exporters of organic matter into 'sinks' because they trap floating marsh grass and seaweeds brought in by the tide. The overall effect of these changes has probably been to reduce the relative importance of saltmarsh production to coastal ecosystems.
'Reclamation' of salt marshes was carried out without recognition of their potential role in coastal food webs, and yielded high quality farmland that has been an important part of development in the region. In recent years, however, collapse of hay markets and the high cost of installing effective drainage has somewhat tarnished the image of farmed marshlands, despite demonstrations that when appropriately managed they produce the highest yields in the region. Consequently, they have been considered for other uses, including landfills, industrial, commercial and residential development. In many areas around the Bay of Fundy extensive areas of reclaimed salt marsh that are no longer deemed necessary for agricultural are being converted to freshwater impoundments to provide waterfowl habitat. Ducks Unlimited Canada in conjunction with the Eastern Habitat Joint Venture Program have been spearheading these efforts. Some 100 wetland impoundments in the Gulf of Maine watershed, encompassing over 8,100 hectares have already been developed (Gulf of Maine Times, Vol.2 #1), including the 320 hectare Belleisle Marsh on the Annapolis River Estuary. This trend is likely to intensify in the future. Little if any consideration appears to have been given to the feasibility or potential ecological benefits to the nearby marine ecosystem of restoring these areas as functioning salt marshes. Their important role in support of aquatic food chains, migratory fish and birds, and as habitat for a number of rare or endemic species has generally been ignored.
A salt marsh is an integral part of, and is intimately linked to, the adjacent marine ecosystem. On each tide it receives sediments and nutrients from the sea and returns an abundance of organic matter to nearby coastal waters. In many parts of the Gulf these important exchanges have been impaired by the presence of a wide range of tidal restrictions as outlined in section 4.3. For example, in coastal New Hampshire some 50 tidal restrictions have been identified that affect 20% of the remaining salt marsh (Shelley in press). The trophic consequences of this reduced interaction for the marshes and the adjacent marine habitats are poorly understood (Burdick et al. 1994). Such restrictions may also alter the salinity gradients that exists over the marsh by virtue of the dynamic interplay of tidal incursions and freshwater inflows. The net result is that the freshwater influence extends further into the marsh, allowing a variety of other less salt tolerant species to invade the area and change the character of the area. In many marshes in the region there are reports of increasing incursions of purple loosestrife (Lythrum salicaria; L. virgatum.), common cattails (Typha latifolia), common reed (Phragmites australis) and salt cedar (Tamarix gallica) (Shelley in press). For example, the marshes around Essex Bay, MA are showing signs of degradation such as the appearance of invasive plants and upland vegetation (Mountain et al. 1997), and there are many similar examples all around the Gulf. Although their exact impacts on marsh structure and function are poorly understood, they do appear to be crowding out native vegetation and reducing biodiversity. The total area of marshland invaded thus far has not been assessed. Attempts to use satellite remote sensing techniques to monitor invasive plants in Great Marsh, MA were not successful (Shelley in press).
habitat characteristics
Intertidal mudflats are a common habitat in much of the Gulf of Maine and are a dominant feature of the upper Bay of Fundy. Grain size of the sediment is a defining characteristic of the habitat, particularly the proportion of silt-clay particles less than 62 microns in diameter. There is a continuous gradation between different benthic sediment types. Sandy sediments usually have less than 5% dry weight of silt-clay, muddy sands 5-50%, sandy muds 50-90% and true muds in excess of 90% (Folk 1974). The upper few cm of some Fundy mudflats consist of 4.4% sand, 58% silt and 37.5% clay, and have a mean water content of 67.7% (Amos and Mosher 1985). The water content can vary considerably from place to place, greatly influencing the sediment's stability. Large areas of these flats are classified as clamflats and these have provided an economically important harvest of the soft shell clam, Mya arenaria, for many generations of clam diggers throughout the Gulf. In Maine, New Hampshire and Massachusetts there are 14,010 km2 (NOAA 1997) of classified clam flats and in New Brunswick and Nova Scotia 1,276 km2 (D. Walter, Environ. Canada, Dartmouth, NS, unpubl. data 1998), for a total of 15,286 km2 in all.
There is little emergent vegetation on most mud flats and in situ primary production is limited to a surficial growth of microalgal mats, which are also important in stabilizing the sediments against erosion. The import of organic detritus from nearby sources such as salt marshes and macroalgal beds is thus vital to the productivity of the mud flats. Bacteria and fungi play an important role in remineralizing this detrital material and also as food for higher trophic level organisms. Although mudflats are mostly devoid of conspicuous epifauna, they have a diverse and abundant infauna. A tabulation of typical macrofauna of east coast mudflats is provided in DFO (1996). More than 70 macroinvertebrates have been found in the muds of Minas Basin (McCurdy 1979). The most abundant are mud shrimps Corophium volutator, thread worms Heteromastis filiformis, and polychaetes, Chaetozone setosa, comprising 76 % of total numbers. In other areas of the Gulf the bivalves, Macoma balthica, and Mya arenaria and the bloodworm, Glycera dibranchiata are sufficiently abundant to support important commercial harvests. The critical ecological importance of mudflats in the upper Bay of Fundy, particularly of their immense Corophium populations, in the sustenance of millions of migrating shorebirds has been well documented (Hicklin and Smith 1984; Hawkins 1985; Brylinsky et al. 1997). The mudflats are not only important feeding areas for transient populations of shorebirds at low tide, but are equally important for a variety of planktivorous, detrivorous or carnivorous fish that move on to the flats with each rising tide.
habitat issues
The principal threats to mudflats are activities that either directly or indirectly influence sediment dynamics, specifically the processes of erosion, transport or deposition. Mudflats comprise a natural dynamic equilibrium of these three processes and anything that influences one or more of them can alter their extent, composition or biological communities (Daborn 1991). These physical and biological interrelationships in the upper Bay of Fundy area have been well studied by Amos and his colleagues (see Greenberg et al. 1997). Here there are disturbing indications that mudflat characteristics may be changing in ways that jeopardize Corophium populations and the shorebirds dependent on them. Both the sediment composition, water content and stability changed markedly between 1977 and 1994 (Shepherd et al. 1995). It is thought, although not proven, that these changes may reflect a delayed response to construction of dams and causeways on most rivers flowing into the region decades earlier (Brylinsky et al. 1997). In other areas of the Gulf various coastal structures alter currents or restrict tidal exchanges influencing sediment dynamics and degrading nearby mud flats.
Large structures, such as dams and causeways appear to have had major impacts on sediment dynamics, and thus on mudflat habitats, throughout the Gulf of Maine and Bay of Fundy. The following example is but one of many that could be cited. In 1970 a 1050 m long causeway with 5 sluice gates and a fish passageway was placed across the Petitcodiac River near Moncton, NB. Within two years a 20 km long mudflat formed seaward of the causeway. The rates of sediment deposition varied between 1.5 an 2 m per year in many places. By 1981, more than 10 million cubic meters of mud had accumulated in the uppermost 54 km (Bray et al. 1982) and the estuarine cross section was reduced by about 20% (Daborn and Dadswell 1988). A similar large mudflat that formed downstream of a causeway in Windsor, Nova Scotia is slowly being overgrown by cord grass and other vegetation. Thus, large areas are gradually transforming into new salt marsh. Dams and causeways may also cause erosion. It appears that the a causeway constructed at Annapolis Royal lowered the suspended sediment load within the estuary, causing sediment to be withdrawn from remnant salt marsh areas near Fort Anne Historical Site (Greenberg et al. 1997), causing slumping and threatening the integrity of part of the site. In addition, erosion has severely impacted the muddy banks of marshes for 25 km upstream. Similarly, a causeway constructed at Sears Island in Maine caused significant losses of formerly productive mud flats (Shelley in press). Smaller structures such as bulkheads, seawalls, revetments, breakwaters, groins and jetties may also alter sediment dynamics in their immediate vicinity. However, there have been few studies in the Gulf of Maine region concerning their potential impacts on nearby mudflats and clamflats. Individually, they may only cause a localized, relatively small impact, but in areas where there are several of them, the cumulative impact could be significant and widespread.
The softshell clam, Mya arenaria and the bloodworm, Glycera dibranchiata are marine resources of significant economic value in the Gulf of Maine, so the conservation of their mudflat habitat is a matter of some importance. However, the harvesting itself exerts a profound impact upon the resource as well as the physical structure of the mudflat. In clam harvesting the hack is used to physically turn over a clod of sediment that is not replaced in its original orientation. A considerable area of mudflat can thus be disturbed during each tidal cycle. Not only are the clam populations reduced, but more importantly the structure and stability of the habitat is greatly perturbed, particularly in the biologically important surface layers. A similar procedure is used to harvest bloodworms. A good digger can turn over about 460 m2 of flat per tide (Klawe and Dickie 1957). Mawhinney (1991) noted 49 bloodworm harvesters on a mudflat at Starrs Point per tide in one day. Thus as much as 22540 m2 of mudflat may have been turned each tide. Surficial sediment structure must certainly have been altered over this whole area. Impacts of such harvesting on the integrity of the sediment habitat, or on the diversity of the infaunal community, has not been well studied.
The impact of aquaculture operations on physical, chemical, biological, and ecological features of intertidal mudflats have not been well studied (P. Keizer pers. comm.), although similar problems to those reported for subtidal soft bottoms (Wildish et al. 1990; Hargrave et al. 1993; Pohle and Frost 1997) might well be anticipated. Decomposing "mariculture sludge" deposited on intertidal flats may cause similar negative redox potentials, release noxious gases such as ammonia, methane, carbon dioxide and hydrogen sulfide and increase the biological oxygen demand (BOD) in the surficial layers. The associated nutrient enrichment may trigger algal blooms on mudflats. There have been increasing reports of blooms of the green algae Enteromorpha on many mud flats (Harvey in press), and there are recent reports of intertidal areas fouled with "smelly, greasy or slimy deposits" (Harvey in press). The geographic extent of these two problems, or a direct connection to aquaculture operations have not yet been established. The former is the subject of a monitoring program by the University of Maine Cooperative Extension department, while the Conservation Council of New Brunswick proposes to investigate the latter (J. Harvey pers. comm.).
At present, contamination by domestic sewage and river- borne farmyard waste is a far more serious problem and has resulted in the permanent or period closures of large tracts of valuable clam flats throughout the Gulf (NOAA 1991; D. Walter Environment Canada, Dartmouth, NS. unpubl. data). Although the elevated concentrations of the fecal bacteria E. coli renders the clams risky for human consumption it probably has little affect on the clams themselves or on the integrity of their habitat. In fact, up to a point the added organic loading may be ecologically beneficial. However, the excessive organic loading resulting from high volumes of sewage sludge may increase the biological oxygen demand to the point that the mud becomes anoxic and unfit as a habitat for clams and most other macrofauna. How widespread such physical degradation of mudflat habitat is in the Gulf is not known.
habitat characteristics
Beaches are a common habitat feature along much of the coast of the Gulf of Maine. The grain size and other features of the beach substrate varies in different locations, depending on the geological nature of the source material and the energy characteristics of the local environment. Sand beaches are characteristically found to the south of Cape Elizabeth in southern Maine, while to the north bedrock outcrops or boulder, cobble, shingle or muddy beaches are more common (Larsen and Doggett 1990; Gordon 1994). Here we are largely concerned with sand beaches. The source material for most sand beaches in the Gulf are eroding glacial deposits, largely found in the southern Gulf, particularly in Massachusetts and Cape Cod bays (Kelley and Kelley 1995). However, there are also isolated sand beaches as far north as the outer Bay of Fundy, with a few such, as Mavillette beach in St. Mary's Bay Nova Scotia, even having well-developed dune systems. Many of the beaches in the northern Gulf are located near major rivers and appear to receive much of their sand from offshore deltaic deposits formed in earlier times (Kelley and Kelley 1995). It is not yet clear what effect the damming of almost all of these rivers has had on the rate of transport of sediments into coastal waters, or what the long-term consequences of reduced sediment input might be on nearby beaches.
Sand beaches comprise a dynamic interface between the land and sea that are typically located on relatively exposed coasts. However, sand flats can occur in protected estuaries (McLachlan 1983). The sand beach itself is usually considered the region of the shore between the primary dunes and the low water line. Here however we will consider both the beach and associated dunes because they are part of an ecological continuum in a state of dynamic balance. A typical sand beach has a porous structure, little silt and an interstitial space between the grains representing about 40% of the sand volume. This porosity and intense wave action oxygenates the interstitial water to a considerable depth (McLachlan 1983). Despite their apparent uniformity, sand beaches typically exhibits a distinct ecological zonation that is largely due to variations in moisture content of the sand, ranging from almost continuously dry in the upper beach levels to permanently saturated near the low tide line. The upper reaches of the beach are better oxygenated and more variable in temperature than the lower beach zone (McLachlan 1983). These environmental zones are reflected in the distribution patterns of the beach biota.
It was once thought that sand beaches were barren, unproductive and depauperate in biota. However, wide ranging studies in recent decades (reviewed in McLachlan 1983) have shown that some beaches support a diverse and productive community of organisms. However, the beach community and productivity varies greatly in different places, being strongly influenced by the local wave and current regime and the origins of the constituent beach material. Larger attached plants are usually unable to gain a foothold on the shifting, tide-swept substrate of beach itself. Diatoms may be present in the surface layer at some sheltered beaches but are usually absent in exposed sites. This lack of primary production means that the fauna of the beach are dependent upon a continual import of dissolved and particulate organic matter flushed through the sand structure (McLachlan 1983). Much of this organic matter is consumed by bacteria which form an important base for the beach food chain. The bulk of the beach biota are interstitial and live in the pore water between sand grains. The smallest include fungi, algae, bacteria, foraminiferans and ciliates. Metazoans smaller than about 1 mm, termed meiofauna, include nematodes, harpacticoid copepods, turbellarians, oligochaetes, ostracods, gastrotrichs, tardigrades and hydrozoans. Their composition and abundance varies considerably with grain size and organic content. They may be found up to a meter deep in well-oxygenated beaches (McLachlan 1983).
The macrofauna comprise species ranging in size from a few mm to 10 cm. or more that are too large to inhabit interstitial pores. They are usually mobile species and are much less abundant and productive than the microfauna and meiofauna. The commonest are mollusks, crustaceans and polychaetes. Crustaceans tend to be more abundant on exposed beaches while mollusks prefer intermediate areas and polychaetes relatively protected beaches (McLachlan 1983). Their distribution on the beach is usually patchy, reflecting localized food concentrations, wave activity and a tendency of some species to congregate. The abundance and biomass usually tends to increase down the beach towards the low water level. The composition and biomass of macrofaunal communities of a series of sand beaches around the Gulf of Maine have been tabulated by Larsen and Doggett (1990). Careful analysis revealed the presence of three distinctive community groupings in the region. Sand beaches to the south of the Sheepscot River Estuary were dominated by haustauriid amphipods (particularly Amphiporeia virginiana) while those to the north had a lower overall diversity and a greater dominance of annelids. More subtle distinctions characterized the beach communities to the north and south of Mount Desert Island. Examination of the oceanographic characteristics of the regions suggested that the differences may have been attributable to cooler water temperatures in summer in the northern regions of the Gulf because of the greater intensity of vertical mixing of coastal waters. The existence of at least two distinct zoogeographic subregions along the Gulf coast had also been suggested by earlier studies (Bousfield and Laubitz 1972; Bousfield and Thomas 1975; Watling 1979). Birds are also common on sand beaches, with various species of gulls, sanderlings, terns and other shorebirds and seabirds being important predators on beach macrofauna. Terns use some high beach and dune areas for nesting.
Systems of sand dunes, sometimes termed aeolian bedforms (Carter 1988) often extend inland from sand beaches. They are created by prevailing winds moving lighter sand grains from exposed sand flats and depositing them in drifts in areas where wind speed is reduced by obstacles such as vegetation. The dunes are often stabilized by various types of beach grasses and other vegetation, which also trap additional sand and thus gradually expands the dune system. The dunes are often important in maintaining the adjacent beach because the two areas exist in a state of dynamic equilibrium with a constant exchange of sand between them. The dunes are often a source for natural replenishment of beaches after they have been eroded by storms (Carter 1988), and also serve as a repository for excess sand accreting on beaches at other times. In addition to increasing the biological diversity of the region the dunes are also important in absorbing wave attack and sheltering natural and human communities to the landward. The dune vegetation is sensitive to frequent disturbance and once it is destroyed in an area rapid erosion of the dune occurs as the sand is transported elsewhere by the wind. In the Gulf of Maine region the most impressive dune systems occur in the south on Cape Cod and around Massachusetts Bay. Extensive dunes are also present in New Hampshire and southern Maine. Further north in the Gulf the dunes tend to be smaller and occur in scattered pockets such as those behind Mavillette Beach in Southwestern Nova Scotia.
In addition to being an important habitat for marine biota sand beaches and dunes are a much sought after recreational venue for humans. Many beaches also play an important role as protective barriers for productive estuarine lagoons and salt marshes that form behind them. Such areas are often important nursery areas for many species of commercially important fish and shellfish. Beaches also protect the adjacent coast from erosion by storms and wave attack. The sloping expanse of porous sand absorbs much of the wave energy, not by resisting the waves, but by yielding in a dynamic manner that involves transport of the sand itself. Attempts to prevent sand movement by armoring shorelines effectively circumvents this dynamic wave damping process and usually initiate a chain of increasingly costly efforts to maintain the status quo (Lowenstein 1985). The naturally shifting sand barriers have the added advantage of automatically adapting to changing sea levels by moving landward or seaward as needed. Armoring of beaches interferes with this natural adaptive motion and can also entail repetitive and increasingly costly protective measures.
habitat issues
Sand beaches are dynamic systems involving a fine balance between the forces of erosion and accretion, and as such undergo many natural change that are quite independent of any human activities. Many beaches exhibit seasonal patterns in extent and morphology. They may severely erode during repeated winter storms, and large areas of beach habitat can disappear rapidly. However, much of the sand is simply transported a short distance offshore, to be gradually transported back onto the beach by the more moderate wave activity prevailing during the subsequent spring and summer period (Bird 1983). Several other natural factors influencing sand beach habitats are described by Bird (1983) and include rising sea level, geological processes, oceanographic processes and climatic variations. All these can confound any attempts to isolate and assess the impacts of particular human activities.
There are a diverse array of human activities that impinge directly or indirectly on the Gulf's sand beach habitats causing their degradation or loss. The extensive sand beaches of the southern and central areas of the Gulf of Maine are major recreational and tourist attractions that largely sustain many local economies. Even the small scattered beaches of more northerly regions support a variety of recreational activities. There is little information about the direct impact on the beach habitat itself of such intensive recreational use by humans. These are probably slight given that regular tidal incursions ensure constant reworking and rejuvenation of the substrate. In some areas the presence of humans at certain times of the year may interfere with shore-nesting birds such as terns. Where threatened or endangered species are involved seasonal access restrictions are often imposed with some success. The expanding use of recreational vehicles on beaches is a great concern in many areas. Impacts on the beaches themselves are probably minimal and the main worry is the widespread damage to dune vegetation and the dunes themselves by excessive vehicle traffic. An even more critical threat to beach and dune systems in many areas of the Gulf is concentrated housing construction on highly valued beach front properties. Particularly favored and especially vulnerable are barrier beaches (Lowenstein 1985). This not only directly damages dune systems and exacerbates erosion, but inevitably leads to pressures to interfere with natural coastal processes in order maintain the integrity of the real estate. Many such "developed" beaches along much of the southern areas of the Gulf have long been armored and stabilized by the construction of extensive systems of seawalls (Stevenson and Braasch 1994). However, the presence of such seawalls may reduce the supply of beach material from coastal erosion (Bird 1983) and by reflecting the wave energy back onto the beach cause the sand to be eroded away, sometimes undermining the seawall itself (Lowenstein 1985). Such beach erosion in high use areas usually triggers corrective action. Beach replenishment, or nourishment, involves importing large volumes of sand from terrestrial or marine sources (dredge spoils). Unless such sand has characteristics close to the native sand it is likely to alter the nature of the beach habitat and its faunal communities. However, there is little sound information available about the impacts of replenishment on beach habitat. A study in Florida suggested that if care is taken in the selection of material and the timing of replenishment the impacts can be minimized (Gorzelany and Nelson 1987). Groins and other barriers built out from the coast are another popular method of protecting eroding beaches by trapping waterborne sand moving along the shore. Inevitably this causes additional erosion problems elsewhere along the shore ( Bird 1983; Lowenstein 1985).
Dredging in coastal waters may also alter current patterns or enhance intensity of wave attack causing erosion of nearby beach habitat (Bird 1983). Activities elsewhere in the watershed may also have indirect and poorly understood effects on beaches. Thus accelerated upland erosion resulting from forestry, agriculture or other land uses may increase the supply of sediments to coastal areas and lead to a growth of beach habitats (Bird 1983). Conversely dams on rivers may trap sediments and cause regression of beach habitat along the adjacent coastline.
Much of the damage to beach habitat has already taken place and many of the structures responsible for the problems remain. In recent decades that has been a growing awareness of the ecological role of beaches and of the importance of protecting those that remain. Development activities are now being more carefully scrutinized and controlled in most jurisdictions. The Coastal Barriers Resources Act of 1982 in the United States limits federal subsidies for infrastructure development and damage insurance on many undeveloped barrier beaches (Lowenstein 1985). The Nova Scotia Beaches Act stringently regulates any developments in beach areas. Maine is also attempting to reduce development pressures by banning the construction of new seawalls on beaches, although existing ones can still be repaired (Lowenstein 1985; Kelley and Dickson 1994; Joseph Kelley, pers. comm.). In addition, any significant modifications to dune or beaches requires state and local permits (Maine DEP 1993). Aggregate extraction from beaches, once a common and damaging practice in some areas, is now carefully regulated. There are many other such positive initiatives that could be cited. Nevertheless, in spite of these and many other efforts, beach habitat is likely to continue to be lost around the Gulf. Erosion of sandy coastlines are occurring worldwide as a result of a variety of natural processes and human activities acting in concert (Bird 1983).
habitat characteristics
The intertidal zones of the Gulf are characterized by substrates that form a continuous gradient in particle sizes ranging from the finest clays of the Fundy mudflats (section 5.3) to the massive outcrops of bedrock of the Maine coast (section 5.6). Between these two extremes lie the sand beaches described in section 5.4 and the shingle/cobble beaches considered here. Shingle (sometimes termed gravel) beaches are comprised of a mixture of pebbles and small stones of varying sizes, while cobbles are larger stones of several inches in diameter. The rock material may have originally been eroded from nearby cliff faces or transported from considerable distances by waves or tidal currents (Major 1973). Over time, the action of waves and currents moving these stones against one another has ground them into their characteristic rounded or oval smooth shapes. This constant movement and grinding of shingles and cobbles makes this an inhospitable habitat for living creatures and diversity is extremely low (Carter 1988). Some of the species, largely amphipods and nematodes, that have been found in such habitats are listed in (Brown 1993). The primary productivity of cobble beaches is even lower than that of the sand beaches shown in Figure 1, because the constant grinding of the rocks precludes any algal growth. Only in protected areas, where substrate movements are minimal, do green algae sometimes temporarily colonize rock surfaces. The fauna of most shingle/cobble beaches has to rely on the import of organic material by waves and currents.
habitat issues
Probably the only significant threat to shingle and cobble beaches from human activities has been the extraction of the substrate itself for use as aggregate in construction. While this was a common practice decades ago, as evidenced by the cobble fill cores found in many old wharves, most jurisdictions now have legislation that bans or restricts the removal of such material from beach areas. Spilled oil also occasionally washes onto cobble beaches and adheres to the rocks, but this is a high energy environment and the material usually remains for only a short time. In view of the low productivity and relative imperviousness to human impacts it is perhaps not surprising that in the interviews with community groups not a single respondent mentioned shingle/cobble beaches (section 6).
habitat characteristics
The intertidal zone of rocky shores (bedrock or large boulders) along much of the Gulf of Maine is thickly blanketed with dense growths of a fucoid brown algae termed "rockweed". It is sparse in the inner reaches of the Bay of Fundy where high turbidity and unconsolidated sediments dominate. The densest beds appear to occur in the middle and outer reaches of Bay and along the coast of Maine. The intertidal zones of the thousands of coastal islands in this region are also richly vegetated. The more sandy shores of southern Massachusetts Bay and Cape Cod are less conducive to rockweed growth.
These brown to olive-green macroalgae, typically 1 to 2 m in length, are secured to the rocks by sucker-like hold-fasts and their leathery, branching fronds have air bladders that float the plants upright when the tide is in. Five species occur in the region, but only three of them (in order of overall abundance), Ascophyllum nodosum, fucus vesiculosus and Fucus evanescens dominate the shoreline in most areas. The plants are morphologically well-adapted to high energy shores and need turbulent conditions, to circulate nutrients and increase exposure to sunlight, for maximum productivity (Carter 1988). The fucus species tend to predominate on more exposed coasts, while Ascophyllum prefers slightly more sheltered locations (Wippelhauser 1996). The maximum rockweed density usually occurs in areas with moderate wave activity; plants tend to be stunted and sparse in very high energy areas. Rockweeds are most abundant in the intertidal zone, but also extend into shallow subtidal and exhibit a distinct vertical zonation in species composition (Norton 1986). The plants are comparatively long-lived, with Fucus attaining 4 years and some Ascophyllum estimated to be 18 years or more (Keser et al. 1981). The plants grow only slowly in winter and early spring and more rapidly in summer and winter. The general ecology of rockweeds in the coastal waters of Maine has been documented by Wippelhauser (1996)
The ecological importance of rockweeds as a habitat cannot be overstated. They define and create a vegetated rocky shore environment that is critical to many other species. The thick moist blanket of vegetation insulates against heat and desiccation when the tide is out, while the lush floating "forests" that fringe the shore when the tide is in, provide refuge and food for a diverse marine assemblage. The biota is typically more abundant amongst the rockweed than in nearby unvegetated areas. Wippelhauser (1996) has tabulated some 30 species of fish and larger invertebrates that are commonly associated with rockweed in the Gulf of Maine. The beds seem to be particularly important as a nursery area for many species of juvenile fishes providing both forage and refuge from predators (Rangeley 1994; Rangeley and Kramer 1995). Many commercial species such as herring, flounder, cod and hake are associated with rockweed during key parts of their life cycle, and it may also be a critical summer nursery habitat for young of the year pollock (Rangeley 1994). Waterfowl are also drawn to rockweed beds. Black and eider ducks forage amongst the plants for invertebrates at critical times during their life histories; ducklings seeking amphipods and the older ducks seeking periwinkles (Rangeley 1991a). A variety of other ducks, including buffleheads, goldeneye, oldsquaw, whitewing, surf scoters and greater scaup also use the intertidal zone for winter feeding.
Rockweed beds are relatively productive coastal habitats (Figure 1). In St. Margarets Bay in Nova Scotia intertidal macroalgae produce as much as 1000 g carbon/m2/year. Extrapolated over the 2000 miles of rocky Gulf coastline this amounts to an impressive to 5-6 million pounds of carbon per year (Harvey et al. 1995). However, only a few animals, such as amphipods and gastropods (and urchins at the lower tidal fringe) consume the living rockweed plants. Far more rely on the large amounts of detritus produced by the plants or upon the animals feeding on this detritus. In fact, the bulk of the carbon produced by rockweed eventually ends up in the detrital food chain, representing a significant contribution to subtidal benthic productivity (Lenonton et al. 1982). In Passamaquoddy Bay more than 80% of the rockweed production is exported into the estuary and even further offshore (Bradford 1989). Rockweed blades continually erode with wave action and ice scour and much particulate and dissolved organic matter is released. Often, particularly during winter storms, entire plants are torn loose to become part of large floating rafts of vegetation that form offshore and can be several kilometers in circumference. These rafts of slowly degrading material are inhabited by large numbers of zooplankton and other invertebrates that in turn attract larval and juvenile fish and seabirds such as phalaropes and terns (Rangeley 1994). Much of this floating material eventually ends up on beaches as "storm-tossed" weed where it continues to undergo decomposition. In Great Bay Estuary in New Hampshire, 35-85% of the storm-tossed vegetation was rockweed and this material degraded much faster than debris from eelgrass and salt marsh plants (Wippelhauser 1996). These breakdown products are not only important in regenerating nutrients in coastal waters, but are an important nutrition source for intertidal invertebrates. It has also been suggested that the complex colloidal organic compounds released may play a role in the nutrition of adult scallops (Alber and Valiela 1995) and their larvae (Bradford 1989).
habitat issues
The rockweed plants themselves are an important structural component of a productive and diverse habitat, and any stress that threatens the plants jeopardizes the integrity of this habitat. There is little information about general trends in the health of rockweed populations in the Gulf of Maine, although beds along most open coastlines are thought to be healthy. By and large these are resilient plants, and as well, their typical exposed coastal habitat is less prone to reduction in water quality and human disturbances. However, beds in sheltered embayments and estuaries can be and are being adversely affected by a range of human activities. Coastal infilling and development, shoreline armoring, and construction of coastal structures clearly destroy or degrade areas of rockweed bed in the immediate vicinity, either by burial and smothering or by shading them. In some instances, the beds reestablish themselves on the new substrate over time. Although they require considerable light for growth, their shallow intertidal habitat makes them less susceptible to the shading effects of turbid water than other marine plants (Wippelhauser 1996). However, in areas in the Baltic Sea, turbidity and eutrophication have reduced the subtidal depth distribution of rockweed beds (Cederwall and Elmgren 1990) and their overall biomass and productivity. Similarly in some Norwegian fjords reduction in rockweed has been linked to turbidity from untreated sewage, with the beds recovering once sewage treatment began (Bokn et al. 1992). Discharge of heated water into coastal inlets may also affect rockweed beds. Cooling water from a nuclear power plant on the Maine coast raised ambient seawater temperature by as much as 15oC and reduced the standing stock of rockweed in the vicinity of the outfall (Vadas et al. 1976). Petroleum hydrocarbons have been shown to have an adverse effect on the reproduction of rockweed plants (Thursby et al. 1990), a potentially significant problem near port facilities subject to repeated small oil spills. The rockweed plants are particularly sensitive to the chlorate effluent from pulp mills (Lehtinen et al. 1988) and serious damage to beds has occurred in parts of the Baltic. There are no well-documented instances of these types of damage from the Gulf of Maine.
Unquestionably, the greatest present threat to the integrity of rockweed habitat, particularly in areas near the mouth of the Bay of Fundy, is harvesting. The harvest is expanding in spite of the fact that there is only limited information in specific areas (Sharp and Tremblay 1989) about standing stocks and sustainable harvest levels (Rangeley 1991a). It can also be argued that "the sustainable yield or harvest concept......... does not apply when the organism under consideration is a major source of primary production and when it provides the physical structure of an ecosystem." (Rangeley 1991b). Regular removal of a substantial portion of the plant canopy greatly changes the physical structure of the habitat and undoubtedly disrupts the community. Only a few studies have looked at the effect of harvesting, mainly the rate at which the plants regenerate (Keser et al. 1981; Ang et al. 1993) and the beds recover sufficiently for reharvesting (Sharp and Semple 1992). However, there is little information about the short or long term consequences for the many species dependent on this habitat (Gordon 1994). Some of the potential habitat implications of harvesting have been discussed by Mann (1992) and Rangeley (1991b). A study in South West Nova Scotia considered the effects of rockweed harvesting on the abundance and feeding of fish (Black and Miller 1991), but ignored the critical question of the role of rockweed as a nursery for small fish (Rangeley 1994; Black and Miller 1994). Particularly worrisome, in light of this lack of information, is the fact that the most economically desirable and accessible rockweed areas, namely sheltered coastlines and embayments, are also generally important nursery areas for many species (Rangeley 1991a). As part of the ongoing pilot harvesting program in New Brunswick, some areas have been set aside as unharvested control sites (Glyn Sharp pers. comm.). It is hoped that studies of control and harvested areas will provide some insights into ecosystem impacts. A further concern are recent proposals in Nova Scotia to harvest large quantities of storm-tossed macrophyte material from beaches in the outer Bay of Fundy (A. Cameron, Nova Scotia Dept. of Fisheries pers. comm.). This should be resisted until more is known about the role of this nutrient rich material in supplementing the productivity of coastal waters.
habitat characteristics
Islands of varying sizes are important ecological features along much of the coastline of the Gulf of Maine and it has been estimated that there are more than 5000 in the region (Conkling et al. 1995). The overwhelming majority are located in Maine, as that state's Coastal Island Registry lists 4, 617 of them (Harvey et al. 1995). The islands are composed largely of bedrock or glacial deposits (Gordon 1994a), with the former predominating in the northern areas and the latter in more southerly regions around Massachusetts Bay. These islands play a number of roles in enhancing coastal productivity. Their presence increases turbulence and mixing of the coastal currents and thus brings nutrients into surface waters. They also greatly increase the extent of shoreline and thus of the productive intertidal and shallow subtidal areas available to rockweed and kelp beds and the diverse communities associated with them. Many islands are also important nesting or staging sites for seabirds, shorebirds, waterfowl and raptors. Several of their features are particularly important in this respect. Many are remote and undisturbed. Most are free of predatory mammals such as raccoons, rats, and cats that feed on eggs and nestlings. Islands also have a diversity of nesting habitat types suited to a variety of species. For seabirds, the outer islands are also often significantly closer to their principal marine feeding areas. A few of the Gulf islands with important seabird colonies include Machias Seal, Libby, Brothers, Schoodic, Great Duck, Matinicus Seal, Matinicus Rock, Metininic, Manoset and Monomy (Platt et al. 1995b), and there are many others scattered around the Gulf. Interestingly, Eastern Egg Rock in Muscongus Bay, Maine is the southernmost puffin colony in the Gulf of Maine, thanks to a successful puffin restoration project (Shelley in press).
habitat issues
The island nesting seabirds, shorebirds and raptors of the Gulf of Maine are protected by law. Unfortunately, most of their habitats lack the same protected status. The population trends of many species in the region have been summarized by Nettleship (1997), while the natural and human activities that threaten island nesting seabirds and nonbreeding migrants are detailed in Burger and Gochfeld(1994), Schneider and Heinemann (1996) and Nettleship (1997). Residential development is increasing rapidly on islands in some regions. In Massachusetts Bay, for example, development of many of the islands has resulted in loss of nesting habitat for seabirds and shorebirds (Shelley in press). Increasing development on some islands in the outer reaches of the Damariscotta River Estuary threatens to inhibit use of the area by endangered roseate terns and other colonial seabirds (Shelley in press). In Casco Bay, the nesting patterns of terns is being altered by development on islands. Whereas they once nested on several islands they are now largely restricted to only one, greatly increasing their vulnerability (Shelley in press). In fact, throughout the Gulf of Maine there is concern about such enhanced vulnerability because a high proportion of the populations of several species use only a relatively few islands (Dow and Braasch 1996). There is also a growing concern that expanding aquaculture operations in protected nearshore waters, often in the lee of islands, is increasing the level of disturbance to nearby seabird colonies (Dow and Braasch 1996). The concerns are not only for the increasing boat traffic and other human activities in the vicinity, but also for the possibility that scavenging gulls might be drawn to the area. In fact, gulls are a serious threat to seabird colonies throughout the Gulf of Maine. In recent decades gull populations have risen dramatically and their predation on eggs and nestlings of many colonial seabirds, particularly puffins and terns, is of growing concern to seabird biologists (Fry 1992; Nettleship 1997). This is not a natural population growth, but is largely attributable to the gulls ability to adapt to human society and exploit its wastes, whether it be offal from fish plants, discards from fishing boats or garbage in landfills. This "ration subsidy" abnormally enhances their winter survival rate when natural food resources are scarce (Nettleship 1997). Attempts to control gull predation have had only limited success. On Monomoy Island off Cape Cod, where gulls threaten roseate terns and piping plovers, a proposed pilot project to poison gulls caused such a public outcry that the program was put on hold (Gulf of Maine Times, Winter 1997, p. 10).
habitat characteristics
The nearshore benthic habitat extends from the low water line to a depth of about 50 m, and corresponds to the "nearshore shallow community" of Mountain et al. (1994). It includes the seafloor along exposed coasts as well as in estuaries and protected embayments. Subtidal eelgrass meadows and kelp beds are treated elsewhere as distinctive habitats in their own right. Description of subdivisions of this habitat in the Gulf, distinguished primarily by differing substrates and energy levels, are provided in Brown (1993). More simply, the bottom types can be considered as either rocky or unconsolidated (Fefer and Shettig 1980). The former is more prevalent in exposed areas, particularly near coastal rocky islands with intense water mixing, such as outer Penobscot Bay. Exposed bedrock is prevalent in coastal Maine and the outer Bay of Fundy, but are virtually absent farther to the north in the inner Bay of Fundy and to the south in Massachusetts Bay. The total area of rocky bottom is relatively small, with the rocky areas interspersed with extensive areas of unconsolidated material, comprising varying proportions of gravel, sand, silt and clay and highly variable biological communities. In the nearshore zone, i.e. within about 16 km of the coast, the benthic habitat from Casco Bay south consists largely of sand, while to the north silt and clay bottoms are prevalent (Schlee 1973). While the general distributions of bottom types are known, it is only within the last decade that continuous, highly detailed mapping of large areas has been undertaken. Sidescan sonar surveys are providing fine-scale images of the distribution patterns of bottom topography and substrate composition in Penobscot Bay (Kelley et al. 1997), the Bay of Fundy (Greenberg et al. 1997) and other areas of the Gulf of Maine. Such surveys provide a baseline against which future changes in benthic habitats can be reliably monitored.
The benthic communities found in shallow (<50 m) coastal areas generally have more species and larger populations than deeper areas (Mountain et al. 1994). Virtually all invertebrate phyla are represented among the over 500 macrofauna recorded. The high productivity is further supplemented by large inputs of organic matter from terrestrial (runoff) and intertidal (salt marshes, seagrass and rockweed beds) sources. The biological assemblages present in different subtidal areas vary with the type of bottom, particularly the species of juvenile fish (Langton et al. 1989). The species common to the different substrates are presented in Brown, (1993), Fefer and Shettig (1980) and Watling et al. (1988), while Witman (1996) provides a schematic of a food web typical of coastal rocky subtidal areas of the Gulf. Although the species present in different areas is well known, there is little quantitative information about the patterns in distribution in species diversity (Witman 1996), and even less about the changes in these patterns over time. An understanding of such spatial and temporal variability is crucial to detecting changes to benthic habitats resulting from natural processes or human activities. Witman (1996) has begun to monitor the variations in species richness in different rocky areas inshore and offshore. Soft-bottom communities in particular have not been subject to long-term monitoring, and virtually nothing is known about their dynamics (Witman 1996). A variety of finfish and shellfish abound in these coastal waters and sustain important commercial and recreational fisheries. In addition, subtidal areas are increasingly recognized as critical habitat for bottom spawning fish such as winter flounder and herring, which need clean, coarse substrate for their eggs.. Estuaries, embayments, fjords and surf zones are also important nursery areas for other commercially important fish species (Mountain et al. 1994; Langton et al. 1989), while coastal cobble and shingle bottoms are productive lobster habitat (Shelley in press).
habitat issues
Large areas of nearshore benthic habitat have been degraded in many parts of the Gulf of Maine, particularly in estuarine areas and protected embayments close to major population centers (Shelley in press). In large ports, such as Boston, Portland and Saint John, benthic habitats have long been severely degraded or irretrievably destroyed by the construction of wharves and other facilities, frequent dredging and release of wastes. The seafloor in these areas is virtually anoxic and devoid of macrofauna. Ongoing coastal developments, such as the expansion of shipbuilding facilities in the lower reaches of the Kennebec River, are expected to result in the loss of even more subtidal benthic habitat (Shelley in press). Nearshore benthic habitats throughout the Gulf are being subjected to a wide range of other stresses attributable to land-based activities, including excessive sedimentation and turbidity, smothering by wood wastes, dredging, dragging by heavy fishing gear, burgeoning aquaculture development, commercial shipping and recreational boating. Only the most destructive of these activities can be considered in detail here. The threat from dredging is discussed in connection with eelgrass beds (section 5.10).
A concern of many community groups and scientists around the Gulf is the damage that has been done, and is still being done, to subtidal habitats in estuaries and coastal embayments by the heavy fishing gear used in harvesting groundfish and shellfish. In some areas, such as the Damariscotta Estuary and Casco Bay, intensive, repetitive disturbance by mobile gear is thought to be one of the principal threats to subtidal habitats (Shelley in press), as well as more extensively throughout the Gulf of Maine (Witman 1996). Although detailed information is sparse it is believed that many different subtidal habitats are being degraded by such repeated disturbance. Vegetation in eelgrass and kelp beds is being uprooted and destroyed. The structural integrity of soft-sediment habitats, particularly the critical surficial layer, is being disturbed over large areas. The constant dragging also reduces the structural diversity (by leveling bottom features) of the habitat, with unknown ecological consequences. Fine sediments are constantly resuspended and transported away by tidal currents (Les Watling pers. comm.) not only altering the sediment composition but also, at least temporarily, smothering nearby gravel bottoms (Shelley in press). Although there have been many attempts worldwide to quantify trawling and dragging impacts on both hard and soft substrates (reviewed by Langton 1994) there is little scientific consensus about the nature, ecological significance or persistence of any impacts on the benthic habitat. Some studies suggest that trawling degrades fish habitat (Wenner 1983) and reduces the diversity of non target species (Jones 1992). A study on intertidal mud flats in the upper Bay of Fundy, where groundfish trawling occurred at high tide, suggested that effects were minimal (Brylinsky et al. 1994). Much of the uncertainty reflects the difficulty in long-term monitoring of this patchy habitat in insufficient detail to detect change. The frequency at which trawling occurs also influences the impact and rate and degree of habitat recovery (Langton 1994). It is anticipated that the ongoing surveys of large areas of subtidal benthos, using sidescan sonar and other remote sensing techniques, will eventually provide more comprehensive information about impacts of mobile gear on benthic habitats.
The impacts of aquaculture wastes on benthic habitats have been the focus of a great deal of research. The large amounts of organic wastes generated by fish farms ultimately descend to the sea floor where they accumulate as "mariculture sludge" (Wildish et al. 1990). The decomposition of this waste may result in a negative redox potential in sediments, release noxious gases such as ammonia, methane, carbon dioxide and hydrogen sulfide, and significantly increase the biological and chemical oxygen demand in the sediment and overlying water (Wildish et al. 1990, Hargrave et al. 1993). As a result of this habitat degradation, there are also significant changes in community structure in the vicinity of salmon farms (Lim 1991; Hargrave et al. 1993). An extensive survey of aquaculture sites in New Brunswick revealed that 15% exhibited high levels of benthic degradation while the other 85% were low to moderately degraded (Thonney and Garnier 1993). Impacts were most pronounced at sites with low flushing rates. Although these adverse impacts occur immediately adjacent to the fish farms, there is little information about the possible long-term impacts at depositional sites more remote from the farms, or about the total area of coastal habitat affected in the long-term by the many aquaculture operations. There are concerns that over time this material may accumulate in depositional areas. The concern over aquaculture is most urgent in the Bay of Fundy, where fish farming began in the region and where its growth has been most dramatic. Many involved in the traditional fisheries and most conservation organizations feel that much of the coastal environment is at risk (Milewski et al. 1997), while the aquaculture industry and government regulators seem confident that adverse impacts are mostly localized, minimal and manageable. Almost all research and monitoring of aquaculture impacts is being funded, managed or carried out by the aquaculture industry or the federal and provincial departments of fisheries, all of whom have a long-standing commitment to fostering the continued growth of the industry (DFO 1991; 1995).
The accumulation of wood wastes on the seafloor seems to be common in many estuaries. Almost all significant rivers flowing into the Gulf once had sawmills or pulpmills that released large quantities of wood chips and bark into the water. In addition, massive log drives on larger rivers, such as the Kennebec and Androscoggin, generated large quantities of wood waste (Shelley in press). These accumulated in thick layers on the nearby seafloor and in many areas, such as Machias Bay, have persisted for many decades after the mills disappeared and the drives ceased. The wastes smother the bottom habitat and in some areas deposits are thought to be meters deep (Harvey in press). Sometimes the material is remobilized by storms and redistributed, presumably smothering additional benthic habitat. Brown (1993) characterized this as a "culturally derived" habitat. The deposits contain very high levels of organic carbon and their gradual degradation consumes oxygen and nutrients. Although there are many reports of such deposits around the Gulf their overall extent has not been well documented, neither is there good information about their effects on benthic habitats and communities.
habitat characteristics
The inshore pelagic habitat encompasses the water column extending from the surf zone out to a water depth of about 50 m. Thus it includes the water column of estuaries and coastal embayments as well as along open coasts and around coastal islands. It also includes much of the area swept by the coastal current of the Gulf (Lynch 1996). This coastal fringe habitat is highly productive, as evidenced by the coastal zone color scanner images presented in Yentsch et al. (1995), and has a high biodiversity. This is partially attributable to the intense water mixing in the nearshore (Graham 1970; Townsend 1996), particularly around islands (Townsend et al. 1983). There is also a major contribution of nutrients and organic matter from a variety of terrestrial and intertidal sources (see sections 5.2, 5.8, 510). These coastal waters may also be subjected increased sediment loads and reduced salinities from terrestrial runoff, particularly in the vicinity of major rivers. The shallow nearshore waters are also greatly influenced by a variety of physical, chemical and biological interactions with the underlying benthic habitat (Vernberg and Vernberg 1970). The phytoplankton and zooplankton populations characteristic of the inshore areas of the Bay of Fundy are described in Brylinsky et al. (1997) and those of the remainder of the Gulf of Maine in Fefer and Schettig (1980) and Townsend (1984). In some instances diatom blooms may develop in the subtidal surf zone and in semi enclosed embayments with elevated nutrient inputs. The nearshore waters are also important as nursery areas for a wide variety of fish species (Mountain et al. 1994; Langton et al. 1989) and species of marine and anadromous fish also migrate seasonally along the coasts (Rulifson and Dadswell 1995).
habitat issues
The principle potential threat (excluding toxic contaminants) to the water column habitat in inshore areas around the Gulf of Maine is the increasing incidence of eutrophication, particularly in estuaries and protected embayments. The nature of this problem is described more fully in section 4.7, while some of the possible sources of the excess nutrients are identified in section 4. Concerns have been raised about the effects of aquaculture on seawater quality in the vicinity of the fish farms. These have largely focused on the reduction of dissolved oxygen levels, both as a consequence of fish respiration and biological/chemical oxygen demand resulting from breakdown of organic wastes, and the increased concentrations of nutrients such as ammonia and nitrates (Wildish et al. 1993). There is concern that these added nutrients could trigger blooms of toxic microalgae that would have lethal or sublethal effects on both farmed and wild fish stocks (Wildish et al. 1992). Significant localized declines in oxygen and increases in ammonia concentration have been found in the immediate vicinity of fish cages, particularly where tidal flushing is low (Wildish et al. 1993). However, in most coastal areas flushing and mixing are sufficient to minimize undesirable impacts in the water column.
Increased sedimentation loads associated with river runoff, dredging activities or the use of mobile gear could increase the turbidity and reduce water column primary production, at least temporarily, in poorly flushed areas. However, the extent and ecological significance of this potential problem is poorly known in the Gulf of Maine, and in most coastal areas.
habitat characteristics
Beds of eelgrass, Zostera maritima, are a common feature of many estuaries and other protected nearshore areas around the Gulf of Maine. This perennial, vascular, angiosperm (flowering plant) migrated into shallow coastal waters relatively recently in geological terms (Wippelhauser 1996). Although it produces seeds, it mainly propagates vegetatively by a spreading network of rhizomes and roots that anchor it securely it in the soft sediments. Eelgrass beds require an expanse of relatively soft, muddy to sandy sediment, and thus are restricted to relatively low energy wave and current environments. The beds are especially extensive in some estuarine areas, often adjacent to salt marshes, and typically extend from the low tide line to a depth of several meters in clear water.
Eelgrass beds are absent in the turbid inner reaches of the Bay of Fundy. Their distribution in Nova Scotia, New Brunswick and northern Maine is rather patchy with only relatively small scattered beds (Glynn Sharp and Bob Rangeley pers. comm.). Casco Bay appears to have the densest concentrations of eelgrass beds in Maine (Wippelhauser 1996), and much of the coastal area there been mapped in considerable detail by the Maine Department of Marine Resources using remote sensing techniques (Seth Barker pers. comm.). To the south extensive eelgrass beds are also characteristic habitats in most estuarine areas of both New Hampshire and Massachusetts.
Eelgrass beds play a variety of important ecological roles in coastal waters. The intricate network of rhizomes and roots stabilizes sediments against erosion, while the long waving blades reduce current flow and promote deposition of silt and detrital matter onto the bed (Phillips and Menez 1988). The beds are productive and ecologically diverse ecological systems that form the base of a food chain involving both direct grazing and detritus production. The plants, particularly the rhizomes are an important food source for waterfowl such as Black Brant and Canada Geese. Many invertebrates such as snails and urchins also graze extensively on the shoots. Nevertheless, a relatively small proportion of eelgrass is consumed alive, most follows complex detrital pathways (Thayer et al. 1984). The beds function as a nutrient pump, absorbing inorganic material from the sediment deposits and releasing organic products into the water and sediments. The ribbon-like leaves break off and decay to form an organic detritus enriched by bacterial growth. This is an important food source for a many benthic filter feeders and detritivores, which in turn are consumed by larger invertebrates, fish and birds.
Eelgrass beds are important as feeding and refuge areas for a wide range of marine animals. Wippelhauser (1996) tabulated 40 species of fish and invertebrates that are commonly associated with eelgrass beds in the southern Gulf of Maine. They are particularly important nursery areas for larval and juvenile stages of a variety of commercially important finfish and shellfish such as winter flounder, tautog, lobsters, mussels and scallops (Heck et al. 1989; 1995; Dow and Braasch 1996). The beds play a particular role as larval traps for mussels and bay scallops, large numbers of which attach to the blades where they grow for a period before dropping off on to the underlying sediment or dispersing over large areas of the estuary (Fonseca et al. 1984; Newell 1994). The sparse eelgrass beds of southeastern New Brunswick are thought to be important habitat for isolated populations of rare species such as the northern pipefish (Rangeley pers. comm.). Eelgrass is highly ranked on the list of important species of the US Fish and Wildlife Service and was identified as one of four priority habitats by participants at a Gulf of Maine Council Workshop (Stevenson and Braasch 1994). The critical importance of eelgrass beds to the Gulf's coastal ecosystem was clearly demonstrated in the 1930's. At that time a wasting disease destroyed east coast eelgrass beds resulting in catastrophic declines in Black Brant and Bay scallops as well as in populations of many other species (Wippelhauser 1996).
habitat issues
There are many threats to eelgrass beds in the Gulf of Maine. The plants are sensitive and susceptible to a range of environmental stresses, both natural and anthropogenic (Short and Wyllie-Echeverria 1996). The natural stresses cause periodic fluctuations in the health and extent of eelgrass beds, making it extremely difficult to assess the impacts of specific human activities. Winter storms frequently destroy large areas of eelgrass. Overgrazing by species such as geese and sea urchins (Phillips and Menez 1988) and excessive sediment disturbances by foraging fish, skates and crabs can adversely effect beds. Periodic outbreaks of a wasting disease caused by a slime mold infection (Labrynthula sp.) can be especially devastating. Beds throughout the Gulf were decimated by the disease in the 1930s (Rasmussen 1977). Although the disease had run its course by the 1940s, healthy beds were only fully reestablished in the 1960s (Short et al. 1987). There have been occasional more localized outbreaks of the disease in various parts of the Gulf causing unpredictable regional oscillations in eelgrass abundance (Wippelhauser 1996). The outbreak of disease is probably associated with other environmental stresses (Short et al. 1987).
The plants are very sensitive to changes in water quality, particularly increases in turbidity. Thus, any activity that increases sediment loads in estuaries, such as runoff and erosion from agriculture or forestry may have detrimental impacts on eelgrass beds. It is feared that logging in the watershed of Frenchman Bay in northeastern Maine may increase siltation in the estuary and threaten eelgrass beds (Shelley in press). In many estuaries an important water quality issue that may affect eelgrass is eutrophication associated with excessive nutrient loading. Adverse effects on the health and distribution of eelgrass beds has been particularly linked to nutrient enrichment of groundwater by septic wastes generated in nearby residential developments (Short and Burdick 1996). Mesocosm experiments have shown that under eutrophic conditions eelgrass growth is reduced by shading from phytoplankton blooms, proliferating epiphytes and competing macro algae. (Short et al. 1995).
Shoreline development and modification have also adversely effected eelgrass beds. Land filling permanently destroys the beds and although carefully regulated in most jurisdictions may still be occurring on a small scale. In some instances, land filling is permitted provided an equivalent area of eelgrass habitat is established elsewhere. A large scale, long-term project is currently assessing the efficacy of eelgrass transplantation as a mitigative measure (Fred Short pers. comm.). Other shoreline developments such as wharves, groins or other structures that alter current flows can lead to erosion, smothering or shading of nearby eelgrass beds. Plants are also sensitive to localized increases in water temperature, such as those associated with coastal coal-fired or nuclear electrical generating stations. In Florida waters, 60% of eelgrass was killed when water temperatures rose 4o above ambient and more subtle impacts on growth and reproduction may occur at lower temperatures (Phillips and Menez 1988)
Bottom disturbance is chronic in many estuaries and coastal areas of the Gulf of Maine and can be particularly damaging to eelgrass beds. They are particularly vulnerable to dredging in shallow waters. Not only can the beds be destroyed directly, but the associated silt plumes can shade or smother beds for considerable distances. Dredging also alters the structural integrity of the substratum thereby inhibiting recolonization (Phillips and Menez 1988). Disposal of the dredge spoils in shallow water may also adversely affect eelgrass beds. Nowadays, dredging activity is normally carried out in a manner that minimizes the direct destruction of eelgrass beds. However, the many indirect effects are often unrecognized and may pose a continuing threat. The use of heavy fishing gear in shallow coastal bays and estuaries to harvest finfish and shellfish may also damage extensive areas of eelgrass beds. Because these are important nursery areas, this in turn can have negative effects on the fisheries themselves. For example, intensive harvesting of bay scallops reduced the abundance of eelgrass beds, and since larvae initially settle on the eelgrass, there was a subsequent decline in the scallop harvest (Fonseca et al. 1984). The rapid expansion of marina facilities and moorings in many shallow, protected estuarine areas is also exacerbating the destruction of eelgrass beds. The increased boating activity in these areas is also very destructive, as propellers cut up and uproot the plants and churn up bottom sediments. Oils spills in coastal waters can damage eelgrass beds and cause loss of productivity and growth. Usually the effects are localized and only above ground growth is killed, allowing the rhizomes to regenerate relatively rapidly (Jacobs 1982). However, repeated small spills at some larger ports could eventually destroy eelgrass beds in the vicinity.
habitat characteristics
The term kelp encompasses a number of brown laminarian algae that dominate rocky subtidal coastal areas in the Gulf of Maine. The most abundant species are Agarum cribrosum, Laminaria digitata, Laminaria longicruris and Alaria esculenta. These plants can be large; Agarum may attain a length of 5 feet, Alaria 11 feet and Laminaria up to 30 feet. Unlike seagrasses, they have no roots, but adhere to rocky substrates by a sucker like holdfast and absorb nutrients directly from the water with the leaf like fronds. They are not found in soft sediments or sands, but on bedrock outcrops and large boulders or cobbles (Dayton 1985). In the Gulf they are abundant in rocky coastal subtidal areas, but sparse in estuaries because of unsuitable substrate and low salinities. The plants do best in turbulent conditions, as oxygen and nutrient assimilation is enhanced (Dayton 1985) and they are well adapted to the stresses of waves and currents (Carter 1988). Kelps grow from the subtidal fringe (low water mean) to depths of 50 meters or more. They exhibit zonation, with Alaria tending to occupy subtidal fringes, Laminaria the intermediate depths and Agarum in deeper areas, but there is a considerable overlap (Wippelhauser 1996). In the Gulf growth of kelps occur mostly in late winter and early spring when nutrients are abundant in the water column. Growth is nutrient limited in summer and fall, except where nutrients are continually replenished by tidal mixing such as Cobscook Bay (Wippelhauser 1996). Kelp is widely distributed in rocky subtidal areas of the outer Bay of Fundy and around the Gulf of Maine as well as on offshore ledges and near rocky islands, and in many places forms very dense beds (Vadas and Steneck 1988). In southwestern Nova Scotia standing crop estimates ranged from about 20 to 60 tonnes per hectare, with almost 60% being Laminaria longicruris and the remainder L. digitata (Sharp and Carter 1986). The peak biomass occurred at a depth of about 3 metres.
Like rockweeds, kelp plants define and create a distinctive habitat that is critical to the well being of many other species. They enhance the structural complexity of the area, and provide food and refuge. Wippelhauser (1996) tabulates 12 fish and 51 invertebrate species that are commonly associated with kelp beds in the Gulf of Maine. They are among the most productive of coastal habitats (Figure 1). Along North Atlantic coasts production rates usually average 600-1300 g C/m2/y (Dayton 1985). The beds are particularly important as a food source for grazers such as sea urchins, gastropods, amphipods and chitons as well as for a wide variety of detritivores. The kelp beds are also an important habitat for adult and juvenile lobsters (Bologna and Steneck 1993). This was clearly demonstrated in Lobster Bay Nova Scotia in the late 1970s, when urchins decimated the kelp beds and lobster populations declined drastically (Harvey in press). When the urchins succumbed to a virus outbreak both the kelps and the lobsters recovered.
Kelp beds may play an even more important trophic role as producers of organic detritus (Wippelhauser 1996). The blades continually erode, while storms may uproot entire plants. This detached material is readily broken down by bacteria and other decomposers into particulate and dissolved organic matter. The bulk of the kelp production is thus transported into deeper waters (Miller et al. 1971). Dense kelp beds may reduce current speeds in the vicinity and promote sedimentation of organic matter in the area (Wippelhauser 1996). Kelp may also reduce nutrient loading in the water column because of its exceptionally high nitrogen uptake. Under eutrophic conditions growth increases considerably (Conolly and Drew 1985). In one experiment, kelps during daylight hours assimilated as much as 40% of the inorganic nitrogen produced from salmon cages (Subander et al. 1993).
habitat issues
Natural processes such as storms periodically uproot and destroy extensive areas of kelp (Dayton 1985), as demonstrated by the large quantities found drifting at sea and washed up on beaches. However, sea urchins are unquestionably the greatest single threat to the integrity of kelp beds in much of the Gulf, particularly when their populations periodically explode unpredictably. Studies in the coastal waters of Nova Scotia revealed a marked oscillation over a few decades between luxuriant, highly productive kelp beds and a bottom virtually denuded of vegetation as a result of excessive grazing by rapidly increasing sea urchin populations (Johnson and Mann 1988; 1993). Kelp beds along many kilometers of coastline can be decimated by the intense grazing. It has been suggested that the rise in urchin populations may be attributed to a decline in their principal predators such as lobsters, crabs or groundfish as a result of over harvesting or other causes (Dayton 1985). It is also possible that urchins periodically attack kelp more intensively because of a decline in the amount of natural drift algae and detritus (Dayton 1985). If this is the case then heavy rockweed harvesting could foster increased feeding on kelp beds by urchins. Sea urchin harvesting is an important industry in Maine, with over 12000 mt landed in 1992, and it is expanding in New Brunswick and Nova Scotia. Sustainable harvesting of urchins may protect kelp beds from overgrazing (Wippelhauser 1996). Another natural threat to kelp populations is the encrusting bryozoan Membranipora sp., outbreaks of which can completely cover the blade, reducing flexibility and increasing the rate of breakage (Wippelhauser 1996).
The "natural" oscillations in kelp abundance as a result of fluctuations in urchin grazing pressures make it difficult to isolate and assess the impacts of potentially damaging human activities. In addition, kelp grow subtidally, largely invisible to the public. Thus, there is little of the anecdotal information about drastic changes in the habitat, or its component communities, that is available for the more visible, and frequented, intertidal and shallow estuarine habitats. The subtidal patchy distribution also makes it more difficult to monitor populations and detect adverse impacts.
Eutrophication in coastal waters may result in excessive growth of epiphytes and epifauna on the blades causing the plants to sink to the bottom or break off (Dayton 1985). In addition, the turbidity resulting from eutrophication or from increased sediment loading can reduce light penetration and adversely affect the growth and health of the plants. Low levels of dissolved hydrocarbons from spilled petroleum products can be particularly damaging to the reproductive stages of kelp (Steele 1978), although adult plants are relatively resistant. The dragging of heavy bottom gear such as groundfish trawls and scallop dredges through kelp beds can uproot plants and cause considerable damage (Dayton 1985), although the exact nature and magnitude of the impact or the rate of recovery have not been adequately assessed.
Kelp is not now harvested extensively in the Gulf of Maine. In the 1940s up to 3000 tonnes of kelp were harvested each year in southwestern Nova Scotia, largely as a source of sodium alginate, a gelling and emulsifying agent (Sharp and Carter 1986). Surveys in the same area in the 1980s indicated that the yearly production levels were many times the earlier harvest levels and represent "a significant opportunity for exploitation" (Sharp and Carter 1986). Current harvest levels in Maine are very low, being occasionally harvested on a small scale to feed farmed sea urchins (Wippelhauser 1996). There is a concern, however, that if market conditions improve there may be pressure to expand the harvest in various parts of the Gulf. There is little information available about the effects of a regular harvest on the kelp beds themselves or about the short and long-term consequences for the diverse community of organisms that are dependent on kelp beds.
habitat characteristics
The geological and glacial history of the Gulf of Maine has resulted in a variety of submarine features and substrate types that are important in defining offshore benthic habitats (Kelley et al. 1985; Mountain et al. 1994). The different benthic communities and their distributions are generally related to the differing bottom types. The principal macrofaunal assemblages found in the region are described in Watling et al. (1988).
The offshore region is chiefly characterized by a number of deeper basins separated to varying degrees by banks, ledges and ridges. The three largest basins exceed 250 m in depth (Townsend 1996) with bottoms of silty clay or clay (Mountain et al. 1994). Surveys have revealed 125 macrofaunal species in these deep soft bottom habitats (Watling et al. 1988), but this will undoubtedly increase with additional sampling efforts (Witman 1996). The western half of the deep Gulf has a distinctive boreal mud community (Mountain et al. 1994) with lower diversity and biomass than coastal waters. The macrofaunal assemblages found in such areas are described in Packer (1988). The eastern portion of the deep Gulf is characterized as boreal slope transition community. The substrate is also mud, or mud overlying sand and gravel, but the area is more influenced by periodic intrusions of warmer Atlantic water. The community is characterized by species of brittle stars and tubicolous amphipods (Mountain et al. 1994).
The various basins are separated by an irregular array of ridges, ledges and banks. These higher elevations are swept by currents which remove finer silts and expose coarser sands and gravels. (Mountain et al. 1994). The Gulf is bounded to seaward by four large banks that are less than 60 m deep (Lynch 1996). These shallower areas are especially productive because of the upwelling associated with them. In fact, Georges Bank may be one of the most productive areas in the North Atlantic (Gordon 1989). The banks are particularly important fishing grounds for a variety of demersal fish and scallops and are also important nursery areas for a variety of commercial fish species such as cod, haddock, yellowtail flounder and American Plaice (Mountain et al. 1994). There have been a number of surveys looking at seabed characteristics and faunal assemblages at a number of these offshore locations, particularly Georges Bank (Mountain et al. 1994). The general nature of the faunal assemblages associated with these areas and their trophic relationships are described in Witman (1996). However, such studies have been limited to relatively few specific sites, and there is little quantitative information about the distribution and biomass of the biota on a broader Gulf-wide scale.
habitat issues
The loss or degradation of habitat in offshore areas occurs far beyond the scope of public perception and is technically difficult to observe and quantify. Thus, discussion of potential threats to offshore benthic habitats depends largely on isolated observations, informed speculation and theoretical considerations. It is unlikely that many land-based activities will have significant direct impacts on offshore benthic habitats, except perhaps those associated with the release of contaminants. Nevertheless, it is clear that the ecological processes of coastal waters ultimately have indirect, subtle and long-term influences on the productivity and health of the whole Gulf. Thus, the loss and degradation of coastal habitats described elsewhere will, in the long-term, have repercussions in the Gulf's deepest basins and on its outermost banks.
There are, however, a number of immediate and disturbing threats to offshore benthic habitats. Unquestionably the greatest disturbance at present is associated with the extensive and repetitive dragging of heavy fishing gear across large areas of seafloor. Sidescan sonar images reveal widespread furrowing of the bottom in heavily fished areas (Gordon 1989). However, there is still considerable debate about the importance and long-term effects of this disturbance on benthic habitats and communities (see Langton 1994 and Jones 1992 for reviews). Studies are currently being undertaken on Jeffries Ledge to examine the impacts of trawling on benthic habitats and communities (Witman 1996). Exploration for oil on Georges Bank could also pose threats to offshore habitats in the near future. Exploratory drilling in the US sector suggest that any effects on the benthos will be restricted to the immediate vicinity of the well site (Gordon 1989). If exploration is successful and production wells are drilled, then it is likely that construction of a network of submarine pipelines will have more widespread impacts. Seafloor mining of aggregates or other materials could become an issue in the future (Gordon 1989). With growing restrictions on the use of terrestrial sources the industry is looking with interest at high quality deposits of sand and gravel located on the seafloor in various places. Many promising deposits have already been identified and surveyed (Fader and Miller 1994). The initial focus will presumably on deposits in shallower coastal waters, as those offshore are more difficult and expensive to access. The many ecological concerns associated with aggregate extraction are discussed more fully in Pearce (1994) and Percy (1997). Ocean dumping of sewage sludge and industrial wastes is a potential threat that at present does not appear to be widespread in the Gulf of Maine (Dow and Braasch 1996).
habitat characteristics
The offshore pelagic habitat of the Gulf of Maine is a patchwork of many distinctive ecological zones with differing physical, chemical and biological characteristics. It is not surprising, therefore that biological production and marine species are not distributed uniformly. Geomorphologic structures and oceanographic processes act together to create distinctive vertically and horizontally structured water masses. For example, in summer in the central and western Gulf three distinct layers are detectable; Maine surface water to a depth of 50 m, Maine intermediate water from 50 to about 110 meters, and Maine bottom water below this (Brooks 1996). This layering is less evident in the eastern Gulf because of the more intense tidal mixing. Just outside the Gulf, on the slope of Georges Bank, the upper slope water extends to about 150 m and lower slope water below this. The deep channel between Browns and Georges Bank allows an inflow of this nutrient rich lower slope water into the Gulf (Kelley et al. 1995).
Horizontal patterns in water masses and biological productivity are also created by variations in stratification and vertical mixing in different parts of the Gulf (Townsend 1996). Areas where vertical mixing or upwelling are particularly intense are often termed "benthic pumps" because they lift nutrient rich water from great depths into the surface waters where they stimulate growth of phytoplankton (Apollonio and Mann 1995). Strong tidal currents and irregular bottom topography are prevalent in the north eastern Gulf and it there, off South eastern Nova Scotia, between Grand Manan and Penobscot Bay and on Georges Bank that upwelling is most pronounced (Apollonio and Mann 1995). It has been suggested, though not proven, that as a result of the upwelling phytoplankton growth is relatively uniform through the year and most of the production is consumed by the water column community (Apollonio and Mann 1995). In contrast, in the western Gulf where the water column is more stratified in summer there is a massive phytoplankton bloom each spring and much of this production sinks to the bottom to be used by the benthic community. It has been estimated that the well-mixed waters occupy only about a third of the area of the Gulf, yet account for 60% of the total phytoplankton production (Yentsch et al. 1995).
Another feature which adds structure to offshore water masses and plays an important role in patterns of distribution of biological production are oceanographic fronts. These are boundaries between two water masses that have distinctly different temperatures, salinities or densities. Fronts tend to form in relation to major currents, areas of tidal mixing or particular bottom topography and thus are predictably found in certain areas. The most pronounced fronts are found on Georges Bank, Browns Bank, off the southern tip of Nova Scotia and in the outer Bay of Fundy, all areas of strong tidal currents (Gordon 1989). The frontal system associated with the seaward flank of Georges Bank is well described in Perry et al. (1993), as are the zooplanktonic communities associated with it. The marine communities on either side of the front can be very different. Such fronts are usually areas of exceptional biological productivity and are often characterized by an abundance of zooplankton (Perry et al. 1993), fish, marine mammals and seabirds (Apollonio and Mann 1995). Georges Bank has been characterized as among the most productive shelf areas in the North Atlantic (Gordon 1989). Primary production estimates for Georges Bank range from 400-665 gC/m2/y, in contrast to 150-415 gC/m2/y for the Gulf as a whole and the 15gC/m2/m for the turbid areas of the upper bay of Fundy. (Gordon 1986). In spite of this, zooplankton production on Georges Bank appears to be lower than for comparable shelf ecosystems (Gohen and Grosslein 1987). This has been attributed to advection of zooplankton off the Bank (Mountain and Schlitz 1987), but could be associated with a greater transfer of production to benthic communities described earlier. Nevertheless, the valuable demersal and pelagic finfish harvests, the very large scallop fishery, the great abundance of seabirds and the annual congregation of marine mammals in the Gulf of Maine are all attributable to the critical oceanographic processes of tidal mixing, upwelling and frontal system formation.
habitat issues
It is unlikely that any of the land-based activities considered in this report are causing any significant degradation of the offshore pelagic habitat. The likelihood of contaminants from land-based activities finding their way into offshore systems and organisms is dealt with in the scoping paper on contaminants. It is possible that there may be habitat impacts of unknown magnitude if proposed large-scale offshore projects such as drilling for oil on Georges Bank, construction of subsea pipelines across the Gulf or submarine mining of aggregates are ever undertaken. In all these cases the principal physical threat to the water column habitat will probably be associated with localized elevations of sediment loading and turbidity.
6. Ranking the habitat/activity issues
There have been many efforts in recent decades to identify critical environmental issues facing the Gulf of Maine Marine ecosystem. Many of these have been regional in scope, focusing on particular jurisdictions or geographic entities such as specific bays or estuaries. Examples include the ecological characterization and discussion of human impacts on habitats of coastal Maine by Fefer and Schettig (1980), the evaluation of habitat threats and habitat degradation as part of the Casco Bay Estuary Project (CBEP 1996), the assessment of the state of the environment in the Atlantic region of Canada (Eaton et al. 1994; Harding, 1992) and the discussion of environmental issues as part of the St. Croix Estuary Project (SCEP 1997a,b) and the examination of critical ecosystem issues confronting the Bay of Fundy (Percy et al. 1997). There have been many other such initiatives. There have also been notable efforts to assess, and address, the more critical issues in the broader context of the Gulf of Maine as a whole. The most prominent of these have been those of the Gulf of Maine Council on the Marine Environment. In its first action plan (GOMCME 1991) the Council identified priorities and objectives and established a timetable for cooperative action to conserve and protect coastal and marine habitats in the Gulf. A review of the progress made in attaining the objectives has recently been published (GOMCME 1995). This review also provided an opportunity to make adjustments to reflect changing priorities in the region, and culminated in the publication of a second action plan (GOMCME 1996) that focuses efforts on coastal and marine habitats for a five year period. The priorities that will be addressed are 1) protect and restore regionally significant coastal habitats, 2) restore shellfish habitats, 3) protect human health and ecosystem integrity from toxic contaminants in marine habitats, 4) reduce marine debris, and 5) protect and restore fishery habitats and resources. An extensive listing of strategies and actions were developed for addressing these priorities. Another extensive overview of habitat issues in the Gulf of Maine has been prepared by the National Marine fisheries Service (Langton et al. 1994). This publication focuses largely on the research priorities and information needs required to address some of the important environmental issues and is concerned chiefly, but not exclusively, with impacts on benthic habitats in relation to the demersal fisheries. Identification of research priorities and information needs have also been the primary focus of a series of workshops and associated proceedings documents by the Regional Association for Research in the Gulf of Maine (RARGOM) (Stevenson and Braasch 1994; Dow and Braasch 1996).
The present scoping paper, and its attempt to identify important habitat issues and rank them, builds upon and complements many of these earlier efforts. The GPA/CEC goals and focus are somewhat different (see sections 2 and 3) and thus the report focuses chiefly on land-based activities and their physical effects that cause habitat loss or degradation. It makes a particular effort to seek out the views of local communities regarding the importance of the issues, because efforts to solve the environmental problems must involve them and must address their particular concerns. The following describes the steps taken to identify the important issues and rank them in a meaningful fashion.
The first approach was to summarize of the information provided by 48 respondents during telephone interviews. A standard questionnaire (Appendix 1) was used for all interviews, in spite of which it was difficult to obtain entirely comparable information from all respondents. This is largely due to the complexity of the ecological relationships being discussed, but also reflects the particular organizational biases of many of the respondents. The information provided has been summarized in terms of both the habitats of concern and the land-based activities that are perceived to be most damaging to marine habitats. This is presented as simple frequency distributions of the habitats (Figure 2) and the activities (Figure 3) identified in all of the interviews. This too is a somewhat subjective assessment of issues, particularly as it does not rank the concerns expressed by a given respondent. Some identified only one habitat of concern while others discussed several problem areas. Clearly there are important local issues largely confined to particular regions that need to be addressed in a regional context. Nevertheless, the results of the survey do provide some sense of the habitats and activities that may be of general concern. It must be emphasized that although many respondents cited examples of real habitat degradation or loss, others identified only habitats that were perceived to be at risk from particular activities. Thus the frequency distributions reflect a mix of actual changes and potential threats.

Figure 2. Frequency distributions (percent) of marine habitat concerns based on interviews with community groups (white; n=48) and CLF/CCNB compilations (black; n=29).

compilations on estuaries
The second approach is similar to the first in that it also involves the preparation of simple frequency distributions of the habitats (Figure 2) and the activities (Figure 3) of concern. In this instance the data was extracted from the narrative information compiled for each of 29 different estuaries around the Gulf as part of the Restore America's Estuaries Gulf of Maine Estuaries Restoration Project (Shelley in press; Harvey in press). The summaries of information for each of the estuaries was prepared by individuals especially familiar with the particular locality. These differ from the interviews in that the they focus specifically on estuaries. From these compilations it was possible to identify habitat changes and potentially damaging land-based activities of concern in each case. As before the frequency distributions reflect a mix of observed habitat changes and perceived threats.
Relative importance of the issues
The frequency distributions based on the interviews and on the estuary compilations were combined to provide overall frequency distributions of habitat concerns and activity concerns (Figures and 3). The following ranking of public concerns was derived from these frequency distributions. The numbers in parentheses indicate the percentage of the 48 interviews and the 29 estuary compilations in which the concern about the habitat or about the activity was raised.
| Ranking of Activity Concerns |
| 1, Sewage/waste disposal (62%) |
| 2. Dams (49%) |
| 3. Subtidal harvesting (40%) |
| 4. Tidal restrictions (38%) |
| 5. Forestry/sawmills (35%) |
| 6. Residential development (30%) |
| 7. Intertidal harvesting (30%) |
| 8. Aquaculture (27%) |
| 9. Dredging (22%) |
| 10. Tourism/recreation (21%) |
| 11. Agriculture (21%) |
| 12. Diking (17%) |
| 13. Industrial development (17%) |
| 14. Infilling (9%) |
| 15. Mining/aggregate extraction (8%) |
| 16. Fossil fuel/nuclear power (5%) |
| 17. Jetties/groins (5%) |
| 18. Coastal armoring (5%) |
| 19. Tidal power (3%) |
| Ranking of Habitat Concerns |
| 1. Inshore benthic (56%) |
| 2. Salt marsh (47%) |
| 3. Mud/clam flat (44%) |
| 4. Eelgrass bed (19%) |
| 5. Rockweed beds (13%) |
| 6. Inshore pelagic (13%) |
| 7. Sand beach/dune (12%) |
| 8. Coastal islands (9%) |
| 9. Kelp beds (4%) |
| 10. Cobble beach (0%) |
| 11. Offshore benthic (0%) |
| 12. Offshore pelagic (0%) |
Habitat and activity matrix.
A potential impact matrix, consisting of the ranked (top to bottom) land-based activities along one axis and the ranked (left to right) marine habitats along the other, was then developed (Table 1). This arrangement means that activity-habitat combinations (issues) located towards the upper left corner of the matrix are probably of greater public concern than those located further away, all things being equal. For each such issue in the matrix an assessment was made of the potential for the activity to cause significant physical perturbations to the habitat, based on a review of the available scientific literature and discussions with appropriate scientists and managers. Three symbols are used in the matrix to represent no impact, minor/moderate impact or major impact, respectively. These assessments are somewhat arbitrary, particularly in the category "minor/moderate impacts" which tends to be the default in situations where the information may not be sufficient to properly assess the scope of an impact. This becomes increasingly true when considering impacts that are indirect, remote from the source or occur over a longer term. In spite of these shortcomings, the matrix summarizes public concerns and the available scientific information and reasonably distinguishes the more serious impacts from those that are likely to be innocuous or non-existent. Activity - habitat combinations in Table 1 that were judged to result in major impacts were then regrouped in Table 2. Each activity was then reassessed according to a suite of selected attributes in order to identify priority issues. These attributes are as follows:
Spatial scope: number of jurisdictions where problem occurs (3 states, ME, NH and MA, and 2 provinces NB and NS; 5 indicates all).
Temporal scope: probable recovery time if stress removed (short-term <1 yr., mid-term 1-5 yr., long-term >5y).
Ecological impact: general nature of stress and likely ecological effects.
Socioeconomic impact: resources or economic considerations that may be at risk.
General trend: present tendency for activity/impact: increasing, decreasing or stable; historic indicates activity many decades ago, but impacts persist.
A question mark for any attribute indicates uncertainty and general lack of reliable information.
Because all the activity-habitat combinations of minor to moderate significance were dropped in the cut from Table 1 to Table 2, those remaining in the latter rank as either medium or high priority. The following priority issues were identified on the basis of the attributes in Table 2:
| 1. Development on and adjacent to sensitive marine habitats |
| 2. Sewage and eutrophication in coastal waters |
| 3. Dams: loss of fish habitat and alterations in freshwater flow |
| 4. Mobile fishing gear use in estuaries and coastal embayments |
| 5. Salt marsh habitat restoration |
| 6. Tidal flow restrictions in estuaries and coastal inlets |
| 7. Aquaculture impacts on benthic habitats |
| 8. Rockweed and kelp harvesting |
Table 1. Matrix of potential impacts of land-based
activities on Gulf of Maine marine habitats. Habitats are ranked in order of priority from
left to right, and activities from top to bottom, based on assessment of community
concerns (see text for details). Symbols indicate: no impact
, minor/moderate impact
, major impact
, based on available information.
Table 2. Relative significance of impacts of land-based activities on marine habitats based on selected attributes. Spatial scope indicates number of jurisdictions where problem exists (3 states, ME, NH and MA, and 2 provinces NB and NS; 5 indicates all). Temporal scope indicates probable recovery time after stress removed (short-term <1 yr., mid-term 1-5 yr., long-term >5 yr.). Ecological impact indicates nature of stress and likely ecological effect. Socioeconomic impact indicates particular resources or economic considerations possibly at risk. General trend indicates present tendency for activity: increasing, decreasing or stable; historic indicates activity occurred many decades or more ago, but effects persist. A question mark indicates uncertainty and general lack of reliable information.
7. Management objectives for priority issues
The following are synopses of the principal concerns and recommendations for possible management objectives and actions directed towards addressing the priority issues identified in this scoping paper:
1. Development on and adjacent to sensitive marine habitats
concerns: Although industrial and residential development directly on sensitive habitats is now reasonably well controlled in most jurisdictions, there are growing problems with indirect impacts from developments immediately adjacent to these habitats. Some of these include: fragmenting habitats; wastes from storm water run off; excessive nutrients from sewage (see 2 below) and fertilizer use; increased surface run off with increase in impervious surfaces and proliferation of structures (roads, bridges) interfering with normal ground and surface water flows; legal and illegal incremental encroachments; proliferation of waste; disturbance of wildlife; increased sediment loads from construction; demands for protective measures (seawalls, groins, higher dikes).
management objectives: minimize direct and indirect impacts of urban development on sensitive coastal habitats, particularly salt marshes, beach/dune systems and coastal islands.
possible actions:
a) Encourage the identification of sensitive coastal habitats.
b) Encourage appropriate regulatory agencies to recognize the ecological, social and economic value of these sensitive coastal habitats
c) promote the Gulf-wide restriction of urban and industrial development on sensitive coastal habitats
d) Promote the compilation and implementation of comprehensive guidelines for urban development and other human activities in areas adjacent to sensitive coastal habitats.
e) Encourage partnerships with federal, state, provincial, municipal and non-government organizations (e.g. land trusts, watershed associations) and landowners, to protect sensitive coastal habitats through property tax incentives, conservation easements, open space/conservation designation, fee acquisition, and/or management agreement. Enhance opportunities at all levels for matching grant opportunities for local organizations to maintain stewardship responsibility.
2. Sewage and eutrophication in coastal waters
concerns: In many estuaries and protected embayments (particularly in the southern half of the Gulf where tidal flushing is less intense than in the north) nutrient concentrations (from untreated or partially treated sewage, and other terrestrial sources such as fertilizer use) periodically approach levels that cause eutrophication or excessive microalgal growth. This can lead to anoxia, excessive growth of epiphytes, increased turbidity affecting growth of eelgrass beds, and may be implicated in an apparent proliferation of Enteromorpha (green algae) growth on tidal flats. Excessive organic matter from sewage can also render benthic habitats anoxic, greatly reducing biodiversity. Bacteria associated with the sewage although not damaging to the mudflat habitat, necessitates closure of the area to clam digging, a serious economic problem throughout the Gulf.
management objectives: Reduction of inputs of sewage and other and sources of nutrients into estuaries and embayments with low flushing rates.
possible actions:
a) identify coastal areas at risk from eutrophication, based on estimates of rates of expansion of known sources of nutrients, particularly sewage.
b) survey occurrence, frequency and extent of possible biological correlates (indicators) of eutrophication in coastal habitats.
c) identify principal sewage-based and other nutrient sources in coastal areas where there is evidence of significant eutrophication.
d) actively promote and support programs designed to reduce inputs of sewage and other nutrients into coastal waters.
3. Dams: loss of fish habitat and alterations in freshwater flow
concerns: Almost all the rivers flowing into the Gulf are controlled by one or more dams. These alter the pattern of water flow into the estuary, leading to changes in salinity and temperature regimes, as well as in circulation patterns and ice formation. Dams also alter sediment dynamics by trapping sediments and reducing the supply to estuarine and nearby coastal habitats. Their long-term impacts on downstream habitats are only poorly understood. Fine sediments deposited upstream can smother gravel beds used as spawning habitat by anadromous fish such as salmon. Many of the dams make no provision for passage of anadromous fish migrating to and from their spawning areas and many of the fishways that do exist are poorly designed or maintained. Some dams appear to no longer serve a useful purpose. However, proposals for their removal must be carefully evaluated on a site by site basis as habitats have attained a new equilibrium over many decades.
management objectives: Restore access to spawning habitat for anadromous fish and restore more natural water flow regimes in selected areas
possible actions:
a) identify all dams in watershed and assess adequacy of provisions for upstream and downstream passage for key fish species.
b) identify maintenance needs for enhancing fish passage in existing fishways.
c) identify needs for new fishways in dams to allow fish passage
d) identify priorities for maintaining, restoring or constructing fishways and. initiate program of fish passage enhancement on selected rivers
e) identify obsolete or marginally useful structures and evaluate ecological, social and economic costs and benefits of removing or breaching them to restore more normal water flows. Based on this analysis, actively promote the removal of selected structures.
4. Mobile fishing gear use in estuaries and coastal embayments
concerns: Estuaries and coastal embayments are subjected to intense fishing pressures for a variety of shellfish and finfish. Often the harvest involves use of heavy trawls or dredges that are dragged repeatedly over the bottom. The heavy gear alters bottom topography (reducing ecological complexity), destroys benthic plants (eelgrass, kelp) and animals and disturbs the microstructure of the benthic habitat. There is some scientific debate about the exact nature and ecological significance of the impacts and about the ability of the habitat to recover rapidly. There are concerns that some of these inshore areas are important spawning, nursery and refuge areas for commercial fish and shellfish and that frequent trawling/dredging impairs this important function.
management objectives: protect sensitive and productive benthic habitats from heavy gear damage and other resource harvesting impacts.
possible actions
a) develop a classification of bottom habitats according to vulnerability to particular types of heavy gear and conduct high resolution multibeam bathymetric surveys of inshore areas to map the distribution of particularly sensitive habitats.
b) promote the restriction of heavy gear use in sensitive areas as well as the development of harvesting methods that are less destructive to benthic habitats.
c) identify additional areas suitable for designation as coastal marine reserves (or no take zones) designed to protect representative marine nearshore habitats and serve as undisturbed refuges and nursery areas for important fish and shellfish stocks and as marine research sites.
5. Salt marsh habitat restoration
concerns: Around the periphery of the Gulf large areas of productive salt marsh have been completely or partially removed from the marine ecosystem. In the northern areas diking of most of the marshland for agriculture occurred centuries ago. In more southerly regions, ditching for agricultural drainage or mosquito control and infilling for development has also affected large areas of salt marsh habitat. The organic detritus generated by salt marshes is important to the productivity of nearby coastal habitats. Salt marshes are also important waterfowl habitats. In some areas, particularly around the Bay of Fundy, large areas of reclaimed saltmarsh are being converted to freshwater impoundments to enhance waterfowl production rather than to the original salt marsh habitat.
management objectives: restore marine ecological functionality of selected tracts of former salt marsh reclaimed by diking or drained by ditching.
possible actions:
a) inventory land areas reclaimed by diking, or drained by ditching, and assess relative ecological, social and economic costs and benefits associated with restoration of selected areas as a functional saltmarsh.
b) Identify potential candidate sites for restoration or expansion of salt marsh habitat
c) encourage regulatory agencies to recognize the ecological value of salt marshes to the marine environment and to adequately consider the feasibility and potential ecological benefits of the salt marsh option in considering proposals to convert agricultural dikeland to freshwater impoundments.
d) promote pilot projects to restore salt marshes and initiate programs to monitor ecological changes in both salt marsh and adjacent marine habitats.
6. Tidal flow restrictions in estuaries and coastal inlets
concerns: In many estuaries, embayments and tidal inlets assorted road crossings, railroad crossings, causeways, culverts and other structures impede the tidal exchange and reduce the penetration of seawater into marine habitats (salt marshes, mudflats). Their design, siting and construction have been determined almost exclusively by community needs, engineering or economic considerations, with little, if any, regard for the potential impacts on the integrity of, and ecological interactions between, the marine habitats the structures bisect. Although the area of habitat affected by each may be relatively small, their collective impact on marine productivity and habitat integrity could be great. In some salt marshes this reduction in marine influence is allowing the spread of invasive less salt tolerant species (common reed, purple loosestrife, cattails) in the marshes. The overall extent of the invasion is not known nor are the full implications for salt marsh biodiversity and productivity.
management objectives: enhance tidal flow in selected areas where coastal habitats have been significantly degraded as a result of the poor placement, design or maintenance of structures such as culverts, bridges, causeways etc.
possible actions:
a) inventory number, location, nature, condition and utility of restricting structures and assess area and type of habitat lost or degraded as a result of the structures.
b) assess feasibility of changes in location or design of restricting structures at selected sites to enhance tidal exchange
c) evaluate distribution and rate of encroachment of non-native plants into salt marshes as indicators of habitat degradation by changes in hydrologic regimes and tidal restrictions.
d) restore tidal flow at selected test sites and monitor changes in habitat.
7. Aquaculture impacts on benthic habitats
concerns: Finfish aquaculture has skyrocketed in the northern areas of the Gulf over the last two decades, particularly around the mouth of the Bay of Fundy, and is now rapidly expanding in Maine. Although the industry has thus far concentrated on salmon, research is ongoing into the possibility of farming other marine species such as halibut and haddock. There is concern that the large volume of fecal matter and food wastes from these operations settles to the sea floor and degrades the benthic habitat and reduces biodiversity. Studies have shown that moderate to severe degradation can occur in the immediate vicinity of the cages. There is less information, and more controversy, about whether the deposited material might be transported away and accumulate in other coastal habitats (benthic, mudflats) and cause even more widespread impacts. There are also concerns that the activities associated with aquaculture operations located near seabird nesting colonies may disturb the birds and impair reproductive success.
management objectives: ensure that aquaculture in coastal waters is carried out in a sustainable manner with minimal impacts on coastal habitats and marine biodiversity.
possible actions:
a) promote the development and wide implementation of guidelines based on the precautionary principle regarding site selection, stocking densities, husbandry practices and aquaculture facility design.
b) promote the development and wide implementation of comprehensive guidelines for the routine monitoring of habitat conditions at aquaculture sites as well as at potential depositional areas in nearby coastal areas.
c) evaluate effects of disturbance from aquaculture activities on seabird nesting behavior on nearby islands.
8. Rockweed harvesting
concerns: On rocky shores hand harvesting of species of seaweeds such as Irish moss, dulse and rockweed has also been carried out for generations, to provide food, fertilizer, soil conditioner or mulch. However, large-scale commercial harvesting of rockweed for fertilizer and alginate extraction has occurred over the past three decades in Nova Scotia, and on a pilot scale in New Brunswick in the past three years. There are concerns that by harvesting rockweed we are, in effect, harvesting important marine habitat. It is increasingly being recognized that rockweed beds are critically important as spawning, foraging and refuge areas for a wide variety of marine species, including some commercial fish. In addition, detritus from rockweed appears to be an important source of nutrients and organic matter for inshore marine habitats, while large floating mats of rockweed may be important microhabitats offshore for a variety of marine species.
management objectives: ensure that harvesting of macrophytes is carried out in a fully sustainable manner with minimal ecological impacts on the marine communities that they sustain.
possible actions:
a) Promote research to quantify the ecological roles of rockweed as a marine habitat and as a source of organic matter to the coastal ecosystem .
b) Evaluate more fully the impacts of varying levels of rockweed harvesting on the rockweed itself and upon the marine populations associated with it.
c) promote the establishment of conservation zones that are permanently closed to rockweed harvesting to sustain the ecological functions of rockweed in extensive areas of the coastal ecosystem.
ACBJ Research 1997. Projected State Population, 1995-2025. Source: U.S. Bureau of Economic Analysis and ACBJ Research. Demographics Journal, American City Business Journals.[< http://www.amcity.com/journals/demographics/report37/37-1.html>]
Adam, P. 1990. Saltmarsh ecology. Cambridge University Press, Cambridge, U.K. 461 p.
Alber, M. and Valiela, I. 1995. Organic aggregates in detrital food webs: incorporation by bay scallops Argopecten irradians. Mar. Ecol. Prog. Ser. 121:117-124.
Amos, C.L., and Mosher, D.A. 1985. Erosion and deposition of fine-grained sediments from the Bay of Fundy. Sedimentology 32:815-832.
Amos, C.L. 1995. Siliclastic tidal flats. Pp. 273-306 In: Perillo, G.M.E. (ed.). Geomorphology and sedimentology of estuaries. Developments in sedimentology No. 53. Elsevier, Amsterdam.
Ang, P.O., Sharp, G.J. and Semple, R. 1993. Changes in the population structure of Ascophyllum nodosum due to mechanical harvesting. Hydrobiol. 260-261:321-326.
Apollonio, S. and Mann, K. 1995. A peculiar piece of water. Understanding fish distribution in the Gulf of Maine. Pp. 77-95 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Auster, P.J., Malatesta, R.J., Langton, R.W., Watling, L., Valentine, P.C., Donaldson, C.L.S., Langton, E.W., Shepard, A.N. and Babb, I.G. 1995. The impacts of mobile fishing gear on low topography benthic habitats in the Gulf of Maine (Northwest Atlantic): a preliminary assessment. NAFO SCR Doc. 95/21. Ser. No. N2528. 16 p.
Bird, E.C.F. 1983. Factors influencing beach erosion and accretion: a global review. Pp. 709-717 In: McLachlan, A. and Erasmus, T. (eds.). Sandy beaches as ecosystems. Dr. W. Junk Publ. The Hague.
Black, R. and Miller, R.J. 1991. Use of the intertidal zone by fish in Nova Scotia. Environ. Biol. Fish 31:109-121.
Black, R. and Miller, R.J. 1994. The effects of seaweed harvesting on fishes: a response. Environ. Biol. Fish 39:325-328.
Bokn, T.L., Murray, S.N., Moy, F.E. and Magnusson, J.B. 1992. Changes in fucoid distributions and abundances in the inner Oslofjord, Norway: 1974-80 versus 1988-90. Acta Phytogeog. Suec. 78.
Bologna, P.A.X. and Steneck, R.S. 1993. Kelp beds as habitat for American lobster Homarus americanus. Mar. Ecol. Prog. Ser. 100:127-134.
Bousfield, E.L. and Laubitz, D.R. 1972. Station lists and new distributional records of littoral marine invertebrates of the Canadian Atlantic and New England region. National Museum of Natural Science (Ottawa), Publ. in Biological Oceanography 5. 51 p.
Bousfield, E.L. and Thomas, M.L.H. 1975. Post-glacial changes in distribution of littoral marine invertebrates in the Canadian Atlantic region. Proc. NS Institute of Science, 27 (suppl. 3):47-60.
Bradford, B.C. 1989. A demonstration of possible links for a detrital pathway from intertidal macro-algae in the Bay of Fundy. M.Sc. Thesis, Acadia University, Wolfville, NS. 188 p.
Bray, D.I., Demerchant, D.P. and Sullivan, D.L. 1982. Some hydrological problems related to the construction of a causeway in the estuary of the Petitcodiac River, New Brunswick. Can. J. Civil Eng. 9:296-307.
Brooks, D.A. 1996. Physical oceanography of the Shelf and slope seas from Cape Hatteras to Georges Bank: a brief overview. Pp. 47-74 In: Sherman, K., Jaworski, N.A. and Smayda, T.J. (eds.). The northeast shelf ecosystem: assssment, sustainability, and management. Blackwell Science, Cambridge Mass.
Brown, B. 1993. A classification system of marine and estuarine habitats in Maine: an ecosystem approach to habitats. Part 1: benthic habitats. Maine Natural Areas Program, Dept. of Economic and Community Development, Augusta, ME. 51 p, + appendix.
Brylinsky, M., Daborn G.R., Wildish, D.J., Dadswell, M.J., Hicklin, P.W., Duncan , C.D., Stobo, W.T., Brown, M.W. and Kraus, S.D. 1997. The Biological Environment of the Bay of Fundy Pp. 63-101 In: Percy, J.A., Wells, P.G. and Evans, A.J. (eds.). Bay of Fundy Issues: a scientific overview. Workshop Proceedings, Wolfville, N.S.. January 29 to February 1, 1996. Environment Canada Atlantic Region Occasional Report no. 8, Environment Canada, Sackville, New Brunswick.
Brylinsky, M., Gibson, J. and Gordon, D.C. 1994. Impacts of flounder trawls on the intertidal habitat and community of the Minas Basin, Bay of Fundy. Can. J. Fish. Aquat. Sci. 51:650-661.
Burdick, D., Dionne, M. and Short, F. 1994. Restoring the interaction of emergent marshes with Gulf of Maine waters: increasing material and energy flows, water and habitat quality, and access to specialized habitats. Pp. 89-91 In: Stevenson, D. and Braasch, E. (eds.). Gulf of Maine Habitat. Workshop Proceedings 12-13 April, 1994. Maine Dept. of Marine Resources, West Boothbay Harbor, Maine. Regional Marine Research Program for the Gulf of Maine and Regional Association for Research on the Gulf Maine. RARGOM Report 94-2.
Burger, J. and Gochfeld, M. 1994. Predation and effects of humans on island nesting seabirds. Pp. 39-60 In: Nettleship, D.N., Burger, J. and Gochfeld, M. (eds.). Seabirds on islands: Threats, case studies and action plans. Proceedings of a workshop, University of Waikato, Hamilton, New Zealand, 19-20 November, 1990. Birdlife Conservation Series No. 1.
Cabilio, P., DeWolfe, D.L. and Daborn, G.R. 1987. Fish catches and long-term tidal cycles in Northwest Atlantic fisheries: a nonlinear regression approach. Can. J. Fish. Aquat. Sci. 44:1890-1897.
Campbell, D.E. 1986. Possible effects of Fundy tidal power development on pelagic productivity of well-mixed waters on Georges Bank and in the Gulf of Maine. Pp. 81-108 In: Daborn, G.R. (ed.). Effects of changes in sea level and tidal range in the Gulf of Maine - Bay of Fundy system. Acadia Centre for Estuarine Research, Acadia University, Wolfville, N.S. Publ. No. 1.
Carter, R.W.G. 1988. Coastal environments. An introduction to the physical, ecological and cultural systems of coastlines Academic Press, N.Y. 617 p.
CBEP 1996. Casco Bay Plan. Casco Bay Estuary Project.
Cederwall, H. and Elmgren, R. 1990. Biological effects of eutrophication in the baltic sea, particularly the coastal zone. Ambio 19:109-112.
Churchill, L.U. 1997. State of Maine aquaculture lease regulationa and monitoring. Poster presentation, DMR, Boothbay Harbor ME.
Colgan, C. S. 1989. Economic Growth Trends in the Gulf of Maine Littoral. Pp. 105 - 115 In: Townsend, D.W. and Larsen, P.F. (eds.). The Gulf of Maine: proceedings of a seminar May 22, 1989, Washington D.C. NOAA Coastal Ocean Program, Regional Synthesis Series Number 1.
Colgan, C.S. and Plumstead, J. 1995. Economic Prospects for the Gulf of Maine. Prepared for the Gulf of Maine Council on the Marine Environment.
Colliton, T.J., McDonough, J.J. III, Remer, D.G. and Lott, D.M. 1992. Building along America's coasts: 20 years of building permits, 1970-1989. Silver Spring, MD: Strategic Environmental Assessments Division, NOAA. 49 p.
Conkling, P.W., Irland, L.C. and Harvey, J. 1995. Views of the forest: timber, history, and wildlands of the Gulf of Maine watershed. Pp. 166-187 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Conolly, N.J. and Drew, E.A. 1985. Physiology of Laminaria III. Effect of a coastal eutrophication gradient on seasonal patterns of growth and tissue composition in L. digitata Lamour and L. saccharina (L.) Lamour. Mar. Ecol. 6:181-195.
Cook, R.H. and Black, E.A. 1993. A strategic overview of mariculture developments in Canada: current status and future directions. ICES - CM - 1993/F. 43 p.
Creaser, E.P. Jr., Clifford, D.A., Hogan, M.J. and Sampson, D.B. 1983. A commercial sampling program for sandworms, Nereis virens Sars, and bloodworms, Glycera dibranchiata Ehlers, harvested along the Maine coast. NOAA Tech. Rept. NMFS SSEF-767. 56 p.
Cutting, R.E., Marshall, T.L., ONeil, S.F. and Amero, P.G. 1994. Status of Atlantic salmon stocks of Scotia-Fundy Region. 1993. DFO Atl. Fish. Res. Doc. 94/22. 20+14 p.
Daborn, G. R. 1997. Fundy marine ecosystem science project: science overview. Pp. 1-9 In: Percy, J.A., Wells, P.G and Evans, A.J. (eds.). Bay of Fundy Issues: a scientific overview. Workshop Proceedings, Jan. 29-Feb. 1, 1996, Wolfville, NS. Environment Canada, Atlantic Region, Occasional Report No. 8.
Daborn, G.R. 1987. Potential impacts of hydro and tidal power developments on the ecology of bays and estuaries. Pp. 334-348 In: Majumdar, S.K., Brenner, F.J. and Miller, E.W. (eds.). Environmental consequences of energy production: problems and prospects. The Pennsylvania Acad. Sci.
Daborn, G.R. (ed.) 1991. Littoral investigation of sediment properties. Final Report. Acadia Centre for Estuarine Research, Publ. No. 17. 239 p.
Daborn, G.R. and Dadswell, M.J. 1988. Natural and anthropomorphic changes in the Bay of Fundy - Gulf of Maine - Georges Bank System. Pp, 574-560 In: El-Sabh, M.I. and Murty, T.S. (eds.). Natural and man-made hazards. D. Reidel Publ. Co.
Day, T. 1994. Information requirements for strategic environmental assessment of marine sand and gravel extraction. Pp. 263-269 In: Wells, P.G. and Ricketts, P. (eds.). Coastal Zone Canada '94: Cooperation in the coastal zone. Conf. Proc. Coastal Zone Canada Assoc. Bedford Institute of Oceanography, Dartmouth, N.S.
Dayton, P.K. 1985. Ecology of kelp communities. Ann. Rev. Ecol. Syst. 16:215-245.
DFO 1991. Aquaculture strategy for the 90s: cultivating the future. Department of Fisheries and Oceans. Minister of Supply and Services, Canada.
DFO 1995. Federal aquaculture development strategy. Department of Fisheries and Oceans. Minister of Supply and Services, Canada.
DFO 1996. By the Sea. A guide to the coastal zone of Atlantic Canada Module 5. Tidal Mudflats . 35 p.
Dow, D. and Braasch, E. (eds.) 1996. The health of the Gulf of Maine ecosystem: cumulative impacts of multiple stressors. RARGOM Report 96-1. 180 p. + append.
Duane, D.B., Culver, S.G. and Stubblefield, W.L. 1988. Sand and gravel resources. In: Sheridan, R.E. and Grow, J. (eds.). The Atlantic continental margin: U.S. Geol. N. Amer. 12.
Eaton, P.B., Gray, A.G., Johnson, P.W and Hundert, E. (eds.) 1994. State of the environment in the Atlantic Region. Environment Canada, Atlantic Region, Dartmouth, N.S. 457 p.
Engler, R.M. 1990. Managing dredged materials. Oceanus 33(2):63-69.
Fader, G.B.J. and Miller, R.O. 1994. A preliminary assessment of the aggregate potential of the Scotian Shelf and adjacent areas. Pp. 230-262 In: Wells, P.G. and Ricketts, P.J. (eds.). Coastal Zone Canada '94. 'Cooperation in the Coastal Zone': Conference Proceedings. Vol 1. Coastal Zone Canada Assoc., Bedford Inst. Oceanog. Dartmouth, NS.
Fefer, S.I. and Schettig, P.A. 1980. An ecological characterization of coastal Maine (North and East of Cape Elizabeth). Volume 2. U.S. Fish and Wildlife Service National Coastal Ecosystems Project. FWS/OBS-80/29.
Fefer, S.I., Famous, N., Thornton, L., and Larsen, P. 1980. Human impacts on the ecosystem. Chapter 3. In: Fefer, S.I. and Schettig, P.A. (eds.). An ecological characterization of coastal Maine (North and East of Cape Elizabeth). Volume 1. U.S. Fish and Wildlife Service National Coastal Ecosystems Project. FWS/OBS-80/29.
Folk, R.L. 1974. Petrology of sedimentary rocks. Hemphill Publ. Co. Austin, Texas. 182 p.
Fonseca, M.S., Thayer, G.W. and Chester, A.J. 1984. Impact of scallop harvesting on eelgrass (Zostera marina) meadows: implications for management. N. Amer. J. Fish. Management 4:286-293.
Fry, D.M. 1992. Point-source and non-point-source problems affecting seabird populations. Pp. 547-562 In: McCullough, D.R. and Barrett, R.H. (eds.). Proceedings of "Wildlife 2000: Populations". Elsevier Applied Science, London and New York.
Gawler, S. 1991. Natural landscapes of Maine: a classification of ecosystems and natural communities. Provisional edition. report of Maine Natural Heritage Program.
Gohen, E.B. and Grosslein, M.D. 1987. Production on Georges Bank compared with other shelf ecosystems. Pp. 383-391 In: Backus, R.H. (ed.). Georges Bank. MIT Press, Cambridge.
GOMCME 1991. Gulf of Maine Action Plan 1991-2000. Gulf of Maine Council on the Marine Environment 34 p.
GOMCME 1992. Gulf of Maine Action Plan Workshop Final Report. Halifax, N.S. 21-22 April, 1992. Prepared for the Gulf of Maine Council on the Marine Environment by the Oceans Institute of Canada. Halifax, N.S.
GOMCME 1995. Work in progress: Five-year report of the Gulf of Maine Council on the Marine Environment, 1990-1995.
GOMCME 1996. Gulf of Maine Action Plan 1996-2001. Gulf of Maine Council on the Marine Environment.
Gordon, D.C. Jr. 1986. A brief review of primary production in the Gulf of Maine and the Bay of Fundy. Pp. 55-69 In: Daborn G.R. (ed.). Effects of changes in sea level and tidal range on the Gulf of Maine - Bay of Fundy system. Atlantic Provinces Council on the Sciences. Acadia Centre for Estuarine Research, Publ. No. 1.
Gordon, D.C. Jr. 1989. Habitat loss in the Gulf of Maine. Pp. 106-119 In: Sustaining our common heritage. Proceedings of the Gulf of Maine Conference. Dec. 10-12. 1989. Portland, Maine.
Gordon, D.C. Jr. 1994. Intertidal ecology and potential power impacts, Bay of Fundy, Canada. Biol. J. Linnaean Soc. 51:17-23.
Gordon, D.C. Jr. and Dadswell, M.J.(eds.). 1984. Update on the marine environmental consequences of tidal power development in the upper reaches of the Bay of Fundy. Can. J. Fish. Aquat. Sci. 1256.
Gordon, D.C.Jr. 1994. Location, extent and importance of marine habitats in the Gulf of Maine. Workshop proceedings, 12-13 April, 1994. Gulf of Maine RARGOM Report 94-2:15-24.
Gordon, D.C.Jr. and Cranford, P.J. 1994. Export of organic matter from macrotidal salt marshes in the upper bay of Fundy, Canada. Pp. 257-264 In: Mitsch, W.J. (ed.). Global wetlands: old world and new. Elsevier Science, New York.
Gordon, D.C.Jr., Cranford, P.J. and Desplanque, C. 1985. Observations on the ecological importance of salt marshes in the Cumberland Basin, a macrotidal estuary in the Bay of Fundy. Estuar. Coast. Shelf. Sci. 20:205-227.
Gorzelany, J.F. and Nelson, W.G. 1987. The effects of beach replenishment on the benthos of a sub-tropical Florida beach. Mar. Environ. Res.21:75-94
Graham, J.J. 1970. Coastal currents of the western Gulf of Maine. Int. Comm. Northwest Atlantic Fish. 7, 19.
Greenberg, D.A. 1983. Modelling the mean barotropic circulation of the Bay of Fundy and Gulf of Maine. J.Phys. Oceanogr. 13:886-904.
Greenberg, D.A. 1984. The effects of tidal power development on the physical oceanography of the Bay of Fundy and Gulf of Maine. Can. Tech. Rep. Fish. Aquat. Sci. 1256:349-369.
Greenberg, D.A., Petrie, B.D. , Daborn, G.R. and Fader, G.B. 1997. The Physical Environment of the Bay of Fundy, Pp. 11-36. In: Percy, J.A., Wells, P.G. and Evans, A.J. (eds.). Bay of Fundy Issues: a scientific overview. Workshop Proceedings, Wolfville, N.S.. January 29 to February 1, 1996. Environment Canada Atlantic Region Occasional Report no. 8, Environment Canada, Sackville, New Brunswick.
Harding, G.C. 1992. A review of the major marine environmental concerns off the Canadian east coast in the 1980s. Can. Tech. Rept. Fish. Aquat. Sci. 1885, vi+38 p.
Hargrave, B.T. 1994. Modelling benthic impacts of organic enrichment from marine aquaculture. Can. Tech. Rept. Fish. Aquat. Sci. 1949. 125 p.
Hargrave, B.T., Duplisea, D.E., Pfeiffer, E. and Wildish, D.J. 1993. Seasonal changes in benthic fluxes of dissolved oxygen and ammonium, associated with marine cultured Atlantic Salmon. Mar. Ecol. Prog. Ser. 96:249-257.
Harvey, J.(ed.) in press . Bay of Fundy Estuaries: baseline assessment of habitat and preliminary list of habitat restoration and protection priorities.. Report #1 Gulf of Maine Estuaries Restoration Project. Conservation Council of New Brunswick, Fredericton, NB.
Harvey, J., Mann, K., Podolsky, R. and Conkling, P.W. 1995. The thin edge between land and sea. Pp. 120-143 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Hawkins, C. M. 1985. Population carbon budgets and the importance of the amphipod, Corophium volutator, in carbon transfer on a Cumberland Basin mudflat, Upper Bay of Fundy. Neth. J. Sea Res. 19:165-176.
Heck, K.L. Jr., Able, K.W., Fahay, M.P. and Roman, C.T. 1989. Fishes and decapod crustaceans of Cape Cod eelgrass meadows: species composition, seasonal abundance patterns and comparison with unvegetated substrates. Estuaries 12:59-65.
Heck, K.L.Jr., Able, K.W., Roman, C.T. and Fahay, M.P. 1995. Composition, abundance, biomass and production of macrofauna in a New England Estuary: comparisons among eelgrass meadows and other nursery habitats. Estuaries 18(2):379-389.
Hicklin, P.W. and Smith, P.C. 1984. Selection of foraging sites and invertebrate prey by migrant Semipalmated Sandpipers Calidris pusilla (Pallas) in Minas Basin, Bay of Fundy. Can. J. Zool. 62:2201-2210.
Intercoast Network 1998. International Newsletter of Coastal Management. Coastal Resources Management Project, Coastal Resources Center, University of Rhode Island. #30, Winter 1988.
Jacobs, R.P.W.M. 1982. Ecological effects of "Amoco Cadiz" oil spill on the seagrass ecosystem at Roscoff, France. Abstract. Pp 173 In: component studies in seagrass ecosystems along west European coasts. Drukkerij Verweij B.V., Mijdrecht.
Jacobson, H.A., Jacobson, G.L., Jr. and Kelley, J.T. 1987. Distribution and abundance of tidal marshes along the coast of Maine. Estuaries 10:126-131.
Jones, J.B. 1992. Environmental impact of trawling on the seabed: a review. N.Z.J. Mar. Freshwater Res. 26:59-67.
Johnson, C.R. and Mann, K.H. 1988. Diversity, patterns of adaptation and stability of Nova Scotian kelp beds. Ecol. Monogr. 58:129-154.
Johnson, C.R. and Mann, K.H. 1993. Rapid succession in subtidal understory seaweeds during recovery from overgrazing by sea urchins in eastern Canada. Bot. Mar. 36:63-77.
Kearney, J. 1994. Sustaining periwinkles. The Fundy North Shore Fishermen's Association seeks a conservation strategy. EcoAlert Nov./Dec. 1994:9-10.
Kelley, A., Kelley, J. and Dickson, S. 1997. Surficial mapping for the Penobscot Bay Project. Penobscot Bay Marine Research Collaborative. Year One Report. Island Institute, Rockland, Maine.
Kelley, J.T. and Dickson, S.M. 1994. Managing Maine's coastal sand dunes : geological inputs to public policy. Abstracts with Programs - Geological Society of America 26(3):28.
Kelley, J.T. and Kelley, A.R. 1995. Waves, tides, and beaches: weather and climate interactions in the Gulf of Maine. Pp. 38-59 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Kelley, J.T., Kelley, A.R and Apollonio, S. 1995. Landforms of the Gulf of Maine. Pp. 19-36 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Kenchington, R.A. 1990. In: Miller, M. and Auyong, J. (eds.). Proceedings of the 1990 Congress on Coastal and Marine Tourism. A symposium and workshop on balancing conservation and economic development, Honolulu, Hawaii 25-31 May, 1990.
Kennish, M.J. 1992. Ecology of estuaries: anthropogenic effects. CRC Press. London. 494 p.
Keser, M., Vadas, R.L. and Larson, B.R. 1981. Regrowth of Ascophyllum nodosum and Fucus vesiculosis under various harvesting regimes in Maine, USA. Bot. Mar. 24:29-38.
Klawe, W.L. and Dickie, L.M. 1957. Biology of the bloodworm, Glycera dibranchiata Ehlers, and its relation to the bloodworm fishery of the Maritime Provinces. Fisheries Research Board of Canada Bulletin 115:37 p.
LaGro, J.A. 1994. Population growth beyond the urban fringe: Implications for rural land use policy. Landscape and Urban Planning 28:143-158.
Langton, R.W., Knowles, R.K and Ward, K.J. 1989. Examination and ecology of potential nursery areas along coastal Maine for groundfish. Final Report. Project 3-426-R. West Boothbay Harbor, ME. Maine Department of Marine Resources. 114 p.
Langton, R.W. 1994. Fishing effects on demersal fish habitats. Pp. 7-8 In: Langton, R.W., Pearce, J.B. and Gibson, J.A. (eds.). Selected living resources, habitat conditions, and human perturbations of the Gulf of Maine. NOAA Technical Memorandum NMFS-NE-106.
Langton, R.W., Pearce, J.B. and Gibson, J.A. (eds.). Selected living resources, habitat conditions, and human perturbations of the Gulf of Maine. NOAA Technical Memorandum NMFS-NE-106. 70 p.
Larsen, P.F. and Doggett, L.F. 1990. Sand beach macrofauna of the Gulf of Maine with inference on the role of oceanic fronts in determining community composition. J. Coast. Res. 6(4):913-926.
Lehtinen, K.J., Notini, M., Mattsson, J. and Landner, L. 1988. Disappearance of bladder wrack (Fucus vesiculosis L.) in the Baltic Sea: relation to pulp-mill chlorate. Ambio 17:387-393.
Lenonton, R.C.J., Robertson, A.I. and Hansen, J.A. 1982. Nearshore accumulations of detached macrophytes as nursery areas for fish. Mar. Ecol. Prog. Ser. 9:51-57.
Lim, S. 1991. Environmental impacts of salmon farming on the benthic community in the Bay of Fundy. Bull. Aquacult. Assoc. Canada 91(3):126-128.
LMER. 1992. Understanding changes in coastal environments: The LMER program. LMER Coordinating Committee. Eos 73 (45):481-485.
Loder, J.W. and Garrett, C. 1978. The 18.6 year cycle of sea surface temperature in shallow seas due to variations in tidal mixing. J.Geophys. Res. 83:1967-1970.
Lowenstein, F. 1985. Beaches or Bedrooms - the choice as sea level rises. Oceanus 28(3): 20-29.
Lynch, D.R. 1996. Gulf of Maine circulation. Pp.15-30 In: Dow, D. and Braasch, E. 1996. (eds.) The health of the Gulf of Maine ecosystem: cumulative impacts of multiple stressors. RARGOM Report 96-1.
Maine DEP. 1993 Coastal beach and sand dune maintenance. Fact Sheet. Maine Department of Environmental Protection 2 p.
Maine State Planning Office. 1997. The Maine Coastal Plan: 1998-2000. Maine Coastal Program Maine State Planning Office, Augusta, ME..
Major, A.P. 1973. Coast, estuary and seashore life. John Gifford Ltd., London. 256 p.
Mann, K.H. 1992. The extent and importance of rockweed as habitat for finfish, shellfish and other species. CAFSAC Res. Doc. 92/116. 8p.
Mawhinney, K. 1991. Use of forage and roost sites in the Minas Basin Hemispheric Shorebird Reserve by migrant semipalmated sandpipers. Prog. Rept. Can. Wildl. Ser. Sackville, NB. 13 p.
McAllister, D.E. and Spiller, G. 1994. Trawling and dredging impacts on fish habitat and bycatch. Coastal Zone 94, 20-23 September, 1994 Halifax, NS. Book of Abstracts: 79.
McCurdy, E.P. 1979. Intertidal invertebrates of Scotts Bay and western Minas Basin, Nova Scotia. MSc. Thesis. Acadia University, Wolfville, NS.
McLachan, A. 1983. Sandy beach ecology - a review. Pp. 321-380 In: McLachlan, A. and Erasmus, T. (eds.) Sandy beaches as ecosystems. Dr. W. Junk Publ. The Hague.
McNeely, J.A. and Thorsell, J.W. 1988. Jungles, mountains, and islands: how tourism can help conserve the natural heritage. Pp. 109-120 In: DAmore, L.J. and Jafari, J. (eds.). Tourism a World Force for Peace. Montreal: First Global Conference.
Milewski, I., Harvey, J. and Buerkle, B. 1997. After the gold rush: the status and future of salmon aquaculture in New Brunswick. Conservation Council of New Brunswick, Fredericton, NB. 60 p.
Miller, M. and Auyong, J. (eds.). Proceedings of the 1990 Congress on Coastal and Marine Tourism. A symposium and workshop on balancing conservation and economic development, Honolulu Hawaii, 25-31 May, vols 1 & 2,
Miller, R.J., Mann, K.H. and Scarratt, D.J. 1971. Production potential of a seaweed-lobster community in eastern Canada. J. Fish. Res. Board Canada 28:1733-1738.
Mountain, D. C., Purinton, T.A. and Pillion, J.A. 1997. Conference summary. Pp: 287-289 In: Donovan, A. and Lefebvre, C. (eds.). Coastal Zone 97: Boston, MA..
Mountain, D.G. and Schlitz, R.J. 1987. Some biologic implications of the circulation. Pp. 392-394 In: Backus, R.H. (ed.). Georges Bank. MIT Press, Cambridge.
Mountain, D.G., Langton, R.W. and Watling, L. 1994. Oceanographic processes and benthic substrates: influences on demersal fish habitats and benthic communities. Pp. 20-25 In: Langton, R.W., Pearce, J.B. and Gibson, J.A. (eds.). Selected living resources, habitat conditions, and human perturbations of the Gulf of Maine. National Oceanographic and Atmospheric Administration Technical Memorandum NMFS-NE 106.
Mulvihill, E.L., Francisco, C.A., Glad, J.B, Kaster, K.B. and Wilson, R.E. 1980. Biological impacts of minor shoreline structures on the coastal environment: state of the art review. US Fish and Wildlife Service, Biological Services Program. FWS/OBS-77/51. 2 vols.
NEFSC, 1995. status of fishery resources off the northeastern United States for 1994. National Marine Fisheries Service, Northeast Fisheries Science Centre, NOAA Tech. Memorandum NMFS-F/NE-108.
Nelson, H. L. and Arnold, C.L. 1996. The Chester Creek Watershed Project; A Progress Report on a unique natural resource management partnership. EPA/NEMO Proj. [<www.epa.gov/region01>].
Nettleship, D.N. 1997. Ecosystem disturbance and seabirds in crisis: Eastern and Atlantic Canada. Invited keynote presentation for WWF Canada's "Atlantic Canada Endangered Species Technical Workshop", Bedford Institute of Oceanography, Dartmouth, NS, 21 March, 1997. Seabird Research Unit, Canadian Wildlife Service, Environment Canada, Report No. 301. 18 p.
Newell, C.R. 1994. Estuary-scale dispersal of post-larval mussels, Mytilus edulis, among eelgrass (Zostera marina) meadows and subsequent recruitment to planted live and mussel shell cultch. Pp. 281 In: Abstracts. Nat. Shellfish. Assoc. 1994 Annual Meeting, April 24-28, Charleston, SC.
Nixon, S.W. 1982. The ecology of New England salt marshes: a community profile. Prepared for National Coastal Ecosystems Team, Office of Biological Services, Fish and Wildlife Service, U.S. Dept. of Interior, Wash. D.C. FWS/OBS-81.
NOAA 1986. National Shellfish Register of Classified Estuarine Waters 1985. National Oceanic and Atmospheric Administration, Strategic Assessment Branch of the National Ocean Service.
NOAA 1991. National Shellfish Register of Classified Estuarine Waters 1990. National Oceanic and Atmospheric Administration: Strategic Assessment Branch of the National Ocean Service.
NOAA. 1992. Red tides: A Summary of Issues and Activities in the United States. Rockville, MD.: NOAA Office of Ocean Resources Conservation and Assessment. 23 p.
NOAA. 1997. NOAAs Estuarine Eutrophication Survey. Volume 3: North Atlantic Region. Silver Spring, MD: Office of Ocean Resources Conservation and Assessment. 45 p.
Norton, T.A. 1986. The zonation of seaweeds on rocky shores. Pp. 7-21 In: Moore, P.J. and Seed, R. (eds.). The ecology of rocky coasts. Columbia University Press, New York.
NSDAM, 1987. Maritime dykelands. The 350 year struggle. The Province of Nova Scotia, Department of Agriculture and Marketing. 110 p.
Odum, W. E. 1970. Insidious alteration of the estuarine environment. Trans. Amer. Fish. Soc. 4:836-847.
Odum, W. E. 1982. Environmental degradation and the tyranny of small decisions. BioScience 32(9):728- 729.
OECD. 1980. The impact of tourism on the environment, General Report. Organization for Economic Cooperation and Development. Paris.
Packer, D. 1988. Community structure of macrobenthic fauna at an offshore Gulf of Maine site, with population structure analysis of the ophiuroid Ophiura sarsi and its trophic relationship to American plaice (Hippoglossoides platessoides). MS Thesis. Univ. Maine, Orono, ME.
Parks, G.S., Ketch, L.A. and O'Reilly, C.T. (in press). Storm surge events in the Maritimes with special emphasis on the Bay of Fundy. Proceedings of the Maritime Atlantic Ecozone Science Workshop, Nov. 11-15, 1997., St. Andrews N.B.
Pearce, J. B. 1994. Mining of seabed aggregates. Pp. 48-50 In: Langton, R.W., Pearce, J.B. and Gibson, J.A. (eds.). Selected living resources, habitat conditions, and human perturbations of the Gulf of Maine. NOAA Technical Memorandum NMFS-NE-106.
Percy, J. 1997. Marine resources of the Bay of Fundy. Pp. 103-137 In: Percy, J.A., Wells, P.G and Evans, A.J. (eds.). Bay of Fundy Issues: a scientific overview. Workshop Proceedings, Jan. 29-Feb. 1, 1996, Wolfville, NS. Environment Canada, Atlantic Region, Occasional Report No. 8.
Percy, J.A., Wells, P.G. and Evans, A.J. (eds). 1997. Bay of Fundy Issues: A scientific overview. Workshop Proceedings, Wolfville N.S. January 29 to February 1, 1996. Environment Canada-Atlantic Region Occasional Report No. 8. Environment Canada, Sackville, N.B.
Perry, R.I., Harding, G.C., Loder, J.W., Tremblay, M.J., Sinclair, M. and Drinkwater, K.F. 1993. Zooplankton distributions at the Georges Bank frontal system: retention or dispersion? Cont. Shelf. Res. 13(4):357-383.
Persky, J.H. 1986. The relation of ground-water quality to housing density, Cape Cod MA. U.S.G.S. Water-Resources Investigations Report 86-4093, Boston MA, 29p.
Phillips, R.C. and Menez, E.G. 1988. Seagrasses. Smithsonian Contr. Mar. sci. 34. Washington, DC.
Platt, D.D., Irland, L.C. and Conkling, P.W. 1995a. Human impact: from swordfish bones to sustainable economies. Pp. 208-232 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Platt, D.D., Podolsky, R. Thurston, H. and Harvey, J. 1995b. The top of the food chain: marine mammals and birds of the Gulf of Maine. Pp. 96-117 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
Pohle, G. and Frost, B. 1997. Establishment of standard benthic monitoring sites to assess long-term ecological modification and provide predictive sequence of community succession in the inner Bay of Fundy, New Brunswick. Atlantic Reference Centre, Huntsman Marine Science Centre.
Rand McNally 1993. The International Atlas. Rand McNally and Co. 315 p.
Rangeley, R..W. 1991a. A critique of the proposed rockweed management and development for the Bay of Fundy. MS Rept. to NB Minister of Fisheries and Aquaculture. 5 p.
Rangeley, R.W. 1991b. An evaluation of rockweed harvest impact on fish populations. MS Rept. to NB Dept. of Fisheries and Aquaculture. 3 p.
Rangeley, R.W. 1994. The effects of seaweed harvesting on fishes: a critique. Environ. Biol. Fishes 39:319-323.
Rangeley, R.W. and Kramer, D.L. 1995. Use of rocky intertidal habitats by juvenile pollock Pollachius virens. Mar. Ecol. Prog. Ser. 126:9-17.
Rasmussen, E. 1997. The wasting disease of eelgrass (Zostera marina) and its effects on environmental factors and fauna. Pp. 1-52 In: McCoy, C.P. and Helfferich, C. (eds.). Seagrass ecosystems, a scientific perspective. Marcel Dekker, New York.
Rhoades, D.C., McCall, P.L. and Yingst, J.Y. 1978. Disturbance and production on the estuarine seafloor. Amer. Sci. 66:557-574.
Rulifson, R.A. 1994. Status of anadromous Alosa along the east coast of North America. Pp. 134-158 In: Anadromous Alosa Symposium. Amer. Fish. Soc.
Rulifson, R.A. and Dadswell, M.J. 1995. Life history and population characteristics of striped bass in Atlantic Canada. Trans. Amer. Fish. Soc. 124:477-507.
Ryder, R.A. and Kerr, S.R. 1989. Environmental priorities: placing habitat in hierarchic perspective. Pp. 2-12 In: Levings, C.D., Holtby, L.B. and Henderson, M.A. (eds.). Proceedings of the National Workshop on Effects of Habitat Alteration on Salmonid Stocks. Can. Spec. Publ. Fish. Aquat. Sci. 105.
SCEP 1997a. St. Croix estuary area: A Profile. St. Croix Estuary Project. St. Stephen, NB.
SCEP 1997b. Caring for our coast: A plan for community management of the St. Croix Estuary area. St. Croix Estuary Project. St. Stephen, NB.
Schlee, J. 1973. Atlantic continental shelf and slope of the United states - sediment texture of the northeastern part. U.S. Geol. Surv. Prof. Pap. 529-L. 64 p.
Schneider, D.C. and Heinemann, D.W. 1996. The state of marine bird populations from Cape Hatteras to the Gulf of Maine. Pp: 197-216 In: Sherman, K., Jaworski, N.A. and Smayda, T.J. (eds.). The northeast shelf ecosystem: assessment, sustainability and management. Blackwell Science, Cambridge, MA.
Scott, D.B and Greenberg, D.A. 1983. Relative sea-level rise and tidal development in the Fundy tidal system. Can. J. Earth Sci. 20:1554-1564.
Sharp, G.J. and Carter, J.A. 1986. Biomass and population structure of kelp (Laminaria spp.) in southwestern Nova Scotia. Can. Manuscr. Rep. Fish. Aquat. Sci. no. 1907. 46 p.
Sharp, G.J. and semple, R.E. 1992. Data base for management strategies Ascophyllum nodosum (Rockweed) resources southwestern New Brunswick. CAFSAC Working Doc. 92/21B.
Sharp, G. and Tremblay, M. 1989. An assessment of Ascophyllum nodosum resources in Scotia-Fundy. CAFSAC Res. Doc. 89/1.
Sharp, G., Ang, P. Jr., and MacKinnon, D. 1994. Rockweed (Ascophyllum nodosum(L.) le Jolis harvesting in Nova Scotia, Canada: its socioeconomic and biological implications for coastal zone management. Pp. 1632-1644 In: Wells, P.G. and Ricketts, P. (eds.). Coastal Zone Canada '94: Cooperation in the coastal zone. Conf. Proc. Coastal Zone Canada Assoc. Bedford Institute of Oceanography, Dartmouth, N.S.
Shelley, P. (ed.). in press. Restoring America's Estuaries. Gulf of Maine Estuaries Restoration Project. Conservation Law Foundation and Island Institute, Rockland ME.
Shepherd, P.C.F., Partridge, V.A. and Hicklin, P.W. 1995. Changes in sediment type types and and invertebrate fauna in the intertidal mudflats of the Bay of Fundy between 1977 and 1994. Canadian Wildlife Service, Environmental Conservation Branch, Sackville, NB. Can. Wildl. Service Tech. Rept. Ser. No.237. 164 p.
Short, F.T. and Burdick, D.M. 1996. Quantifying eelgrass habitat loss in relation to housing development and nitrogen loading in Waquoit Bay, Massachusetts. Estuaries 19(3): 730-739.
Short, F.T., Muehlstein, L.K. and Porter, D. 1987. Eelgrass wasting disease: cause and recurrence of a marine epidemic. Biol. Bull. 173:557-562.
Short, F.T., Burdick, D.M. and Kaldy, J.E.III. 1995. Mesocosm experiments quantify the effects of eutrophication on eelgrass, Zostera marina. Limnol. Oceanog. 40(4):740-749.
Short, F.T. and S. Wyllie-Echeverria. 1996. Natural and human-induced disturbance of seagrasses. Environmental Conservation 23(1):17-27.
Stankey, G.H. and McCool, S.F. 1990. Beyond social carrying capacity. Pp. 597-615. In: Understanding Leisure and Recreation: Mapping the Past, Charting the Future. Venture Press, College Station, PA.
Steele, R.L. 1978. Sensitivity of some brown algal reproductive stages to oil pollution. Pp. 181-190 In: Jensen, A. and Stein, J.R. (eds.). Proc. Ninth International Seaweed Symposium, Santa Barbara, California, 20-27 August, 1977. Science Press, Princeton, NJ.
Stevenson, D. and Braasch, E. (eds.). 1994. Gulf of Maine Habitat. Workshop Proceedings 12-13 April, 1994. Maine Dept. of Marine Resources, West Boothbay Harbor, Maine. Regional Marine Research Program for the Gulf of Maine and Regional Association for Research on the Gulf Maine. RARGOM Report 94-2. 146 p.
Stokesbury, K.D.E. and Dadswell, M.J. 1991. Mortality of juvenile clupeids during passage through a tidal, low-head hydroelectric turbine at Annapolis Royal, Nova Scotia. N. Amer. J. Fish. Management 11:149-154.
Subander, A., Petrell, R.J. and Harrison, P.J. 1993. Laminaria culture for reduction of dissolved inorganic nitrogen in salmon farm effluent. J. Appl. Phycol. 5:455-463.
Thayer, G.W., Kenworthy, W.J. and Fonseca, M.S. 1984. The ecology of eelgrass meadows of the Atlantic coast: a community profile. US Fish. Wildlife Serv. FWS/OBS-84/24. 85 p.
Thonney, J.P. and Garnier, E. 1993. Bay of Fundy salmon aquaculture monitoring program 1992-1993. Report to Environment Canada, Atlantic Region. Canada - New Brunswick Water/Energy Agreement. 83 p.
Thursby, G., Steele, R., Tagliabue, M. and Sheehan, C. 1990. Sexual reproduction in species of brown seaweed, Fucus, to assess damage and recovery from the World Prodigy oil spill. Pp. 291-301 In: Spaulding, M.L. and Reed, M. (eds.). Oil spills: management and legislative implications. Proc. Conf. Newport, RI May 15-18, 1990.
Townsend, D.W. 1984. Comparison of inshore zooplankton and ichthyoplankton populations in the Gulf of Maine. Mar. Ecol. Progr. Ser. 15:17.
Townsend, D.W. 1996. Influence of oceanographic processes on the biological productivity of the Gulf of Maine. Pp. 31-50 In: Dow, D. and Braasch, E. 1996. (eds.) The health of the Gulf of Maine ecosystem: cumulative impacts of multiple stressors. RARGOM Report 96-1.
Townsend, D.W., Yentsch, C.M., Parker, C.E., Balch, W.M. and True, E.D. 1983. An island mixing effect in the coastal Gulf of Maine. Helgol. Meeres. 36:347-356.
U.S. Census Bureau. 1996. Census Bureau data Maps, 1990 [<www.census.gov/lset/abstract/profile.html>]
UNEP 1995. Global programme of action for the protection of the marine environment from land-based activities. United Nations Environmental Program, UNEP(OCA)LBA/IG.2/7. 60 p.
USFWS/GOMCME 1994. Identification of species for priority habitats. US Fish and Wildlife Service Gulf of Maine Project, and Gulf of Maine Council on the Marine Environment. Falmouth, ME. 8 p.
USFWS 1995. Status review for anadromous Atlantic salmon in the United States. U.S. Fish and Wildlife Service and National Marine Fisheries service. 131 p.
Vadas, R.L., Keser, M., and Rusanowski, P.C. 1976. Influence of thermal loading on the ecology of intertidal algae. Pp. 202-212 In: Esch, G. and MacFarlane, R. (eds.). Thermal ecology II. AEC Symposium Series (Conf-750425), Augusta, GA.
Vadas, R.L. and Steneck, R.S. 1988. Zonation of deep water benthic algae in the Gulf of Maine. J. Phycol. 24:338-346.
Valiela, I. and Costa, J. 1988. Eutrophication of Buttermilk Bay, a Cape Cod coastal embayment: Concentrations of nutrients and watershed nutrient budget. Environ. Management 12:539 - 551.
Valiela, I., Foreman, K., LaMontagne, M., Hersh, D. and Costa, J. 1992. Coupling of watersheds and coastal waters: Sources and consequences of nutrient enrichment in Waquoit Bay, Massachusetts. Estuaries 15 (4):443-457.
Van Dusen, K. and A.C. Johnson Hayden (1989): The Gulf of Maine: Sustaining our Common Heritage. Maine State Planning Office, State House, Augusta, ME 04333, Nov. 1989, 57p.
Vernberg, F.J. and Vernberg, W.B. 1970. The animal and the environment. Holt, Rinehart and Winston Inc. New York. 398 p..
Vestal, B., Rieser, A. 1995. Methodologies and Mechanisms for Management of Cumulative Coastal Environmental Impacts. Part 1 - Synthesis, with Annotated Bibliography. NOAA Coastal Ocean Program Decision Analysis Ser. No. 6. NOAA Coastal Ocean Office, Silver Spring, MD. 139 p.
Waiwood, K.G., Haines, K.G. and Reid, J. 1994. Halibut aquaculture research at the St. Andrews Biological Station. Pp. 43-46 In: Science Review 1991 and 1993 of the Bedford Institute of Oceanography, Halifax Fisheries Research Laboratory and St. Andrews Biological Station, DFO, Scotia-Fundy Region, Dartmouth, N.S.
Watling, L. 1979. Zoogeographic affinities of northeastern North American gammaridean amphipoda. Bull. Biol. Soc. Washington 3:256-282.
Watling, L., Dearborn, J. and McCann, L. 1988. General distribution patterns of macrobenthic assemblages in the Gulf of Maine. Pp. 109-119 In: Babb, I., Deluca, M. (eds.). Benthic productivity and marine resources of the Gulf of Maine. Nat. Undersea. Res. Prog. Res. Rep. 88-3.
Wenner, C.A. 1983. Species association and day night variability of trawl-caught fishes from the inshore sponge-coral habitat, South Atlantic Bight. Fish. Bull. 81:537-552.
Wildish, D.J., Martin, J.L and Ringuette, M. 1992. Methods to assess potentially harmful microalgae in the Bay of Fundy salmonid aquaculture industry. Can. Tech. Rep. Fish. Aquat. Sci. 1893. 23 p.
Wildish, D.J., Zitko, V., Akagi, H.M. and Wilson, A.J. 1990. Sedimentary anoxia caused by salmonid mariculture wastes in the Bay of Fundy and its effects on dissolved oxygen in seawater. Pp. 11-18 In: Proc. Canada-Norway Finfish Aquaculture Workshop, Sept. 11-14, 1989, St. Andrews, New Brunswick, Can. Tech. Rept. Fish. Aquat. Sci. 1761.
Wildish, D.J., Keizer, P.S., Wilson, A.J. and Martin, J.L. 1993. Seasonal changes of dissolved oxygen and plant nutrients in seawater near salmonid net pens in the macrotidal Bay of Fundy. Can. J. Fish. Aquat. Sci. 50(5):303-311.
Wippelhauser, G. 1996. Ecology and management of Maines eelgrass, rockweeds and kelps. Maine Natural Areas Program, Department of Conservation, Augusta ME. 73 p.
Witman, J.D. 1996. Dynamics of Gulf of Maine benthic communities. Pp. 51-69 In: Dow, D. and Braasch, E. (eds.). The health of the Gulf of Maine ecosystem: cumulative impacts of multiple stressors. Workshop Report. 18-20 September 1995, Dartmouth College, Hanover, NH. RARGOM Report 96-1.
Yamaguchi, M. and Tyrrell, C. 1997. From planning to implementation: evolution of the storm water management program in the Santa Monica Bay Watershed. Coastal Zone 97 Proceedings. Boston MA.
Yentsch, C.S., Campbell, J.W. and Apollonio, S. 1995. The garden of the sea: biological oceanography. Pp. 60-74 In: Conkling, P.W. (ed) 1995. From Cape Cod to the Bay of Fundy: an environmental atlas of the Gulf of Maine. The MIT Press. Cambridge Mass.
I thank Mike Brylinsky, Graham Daborn, Alison Evans and Chris Hawkins for contributing extensive material for several sections of this report. I greatly appreciate the assistance of Lia Daborn in setting up and conducting the interviews with many non governmental groups. I also extend thanks to the many representatives of community groups, environmental organizations, fisher organizations, First Nations bands, industries and academic institutions who agreed to be interviewed and who provided a wealth of local information about environmental problems throughout the Gulf region. I am very appreciative of the help and encouragement provided by the co-chairs of the Habitat Committee, Stewart Fefer and Bill Ayer. I am especially grateful for the ready assistance of Janice Harvey of the Conservation Council of New Brunswick and Peter Shelley of the Conservation Law Foundation and Island Institute in providing early drafts of their valuable compilation of information on Gulf of Maine Estuaries being published as part of the Restore Americas Estuaries Program. Special thanks to Janice Bennett of the Clean Annapolis River Project for her assistance with many computer related tasks associated with the project.
HABITAT IMPACT QUESTIONNAIRE
1. Identification:
- Organization: Contact Name: Address:
- tel: fax: e-mail:
- Brief description of nature/objectives of organization.
2. Are you aware of any estuarine, coastal or marine habitats in your area that have been, or may be, lost or significantly degraded as a result of any present or anticipated land-based activities in the region (watershed)? [use a, b, c etc. in each section below if more than one habitat/impact is described]
3. What type of habitat is being affected?
- Where is it located (nearest town)?
- What is the approximate size (acreage) of the impacted area?
- What is the exact nature of the impact? [e.g. erosion, burial, siltation, oxygen depletion etc.)
- Does this habitat have any particularly noteworthy ecological or economic value? [e.g. important shorebird feeding area, clam harvesting area etc.]
4. What do you think is/are the principal land-based activity/activities causing this habitat degradation?
5. On what do you base this conclusion ? (direct observation; information from other sources; speculation)?
6. Do you feel that the rate of habitat loss/degradation is increasing or decreasing?
7. Can you direct us to any additional information sources regarding this impact, such as:
- written references
- additional contacts
- ongoing research/conservation projects
GROUPS PARTICIPATING IN SURVEY (contact name in parentheses)
Acadian Seaplants Ltd. (Raul A. Ugarte)
Atlantic Coastal Action Program, Saint John (Sean Brillant)
Atlantic Salmon Federation (John Albright)
Bear River First Nation (Frank Meuse)
Boston Foundation (Glauco Rusga)
Center for Coastal Studies (Stormy Mayo)
Clean Annapolis River Project (Steve Hawboldt)
Cobscook Bay Clam Restoration Project (Will Hopkins)
Darling Marine Laboratory (Les Watling)
Department of Indian Affairs and Northern Development, Atlantic Region (Ivan Rafuse)
Eastern Charlotte Waterways Inc. (Susan Farqueharson)
Ecology Action Centre (Mark Butler)
Enviro-Clare (Jan Slakov)
Federation of Nova Scotia Naturalists (Colin Stewart)
Folly First Nation (Joe Knockwood)
Friends of Casco Bay (Peter Milholland)
Fundy Fishermens Association (Kevin Hurley)
Fundy Fixed Gear Council (Arthur Bull)
Fundy Fixed Gear Council (Lawrence Outhouse)
Georges River Clam Fishery Restoration Project (Sherman Hoyt)
Grand Manan Fishermens Association (Sybil Simms)
Horton First Nation (Mike Halliday)
Jackson Estuarine Laboratory (Steven Jones)
Maine Audubon Society (Rob Ryan)
Maine Coast Heritage Trust (Jane Arbuckle)
Maine department of Inland Fisheries and Wildlife (Ken Elowe)
Maine Department of Marine Resources (Rich Langton)
Maine Lobster Pound Association (Herb Hodgkins)
Maine Lobstermens Association (Pat White)
Maine State Planning Office (Josie Quintrell and Allison Ward)
Massachusetts Audubon Society (Robert Buchsbaum)
Massachusetts Lobstermens Association (William Adler)
MIT Electronics, Yarmouth, NS. (Irene dEntremont)
Natural Resources Council of Maine (Nick Bennet)
Netukulimkewel Commission (Native Council of Nova Scotia )(Tim Martin)
New Brunswick Environmental Network (Mary Ann Coleman)
Penobscot Nation (John Banks)
Penobscot River and Bay Institute (Jo Eaton)
Pleasant Point Passamaquoddy Tribal Government (Heidi Leighton)
Save the Harbor/Save the Bay (Janey Keough)
St. Croix Estuary Project (Rob Rainer)
The Coastal Society, Habitat Conservation Division (John Caskey)
The Collaboration of Community Foundations for the Gulf of Maine (Lissa Widoff)
The Nature Conservancy - Maine Chapter (Barb Vickery)
Union of New Brunswick Indians (Peter Birney)
US Army Corps of Engineers (Jay Clement)
US Fish and Wildlife Service, Gulf of Maine Program (Lois Winter)
Wells National Estuarine Research Reserve (Michelle Dionne)