Some 3.6 million people dwell in the coastal regions rimming the Gulf of Maine and it is safe to say that all derive some benefit from living near a healthy productive marine ecosystem. The livelihoods of many depend on the diverse and valuable harvests of finfish, shellfish and marine plants. Many others have come to rely upon the opportunities it offers for recreation, commerce, shipping and the assimilation of wastes. Large numbers of tourists are also attracted to the coast each year, and are of major importance in sustaining many local economies. There seems little doubt that the incentives for ensuring a healthy and productive ecosystem throughout the Gulf of Maine are many and compelling.

However, there are indications that the health and productivity of the marine system has been, and is increasingly being, compromised by a wide range of human activities occurring along the coasts and throughout the Gulf's immense watershed. Although there is little quantitative information about the early state of the coastal ecosystem, a reading of sparse historical accounts unequivocally shows that many coastal fish and wildlife populations have been decimated and large tracts of once productive marine habitats lost or degraded. Even so, for the Gulf as a whole, many of these ecosystem perturbations are still relatively minor in comparison to the severe impacts evident in many other coastal regions of the world. The most pressing environmental problems are largely confined to coastal waters, particularly in estuaries and harbors, and in areas where population densities are high and expanding. However, if the ecological health of such coastal areas continues to deteriorate, it is likely that in time the integrity and productivity of much of the Gulf’s ecosystem will be compromised. With prompt, concerted efforts it may still be possible to stem the rate of habitat loss and restore some of the more critical ecological functions to degraded habitats, and thus secure the Gulf’s bounty for future generations.

The Global Program of Action (GPA) for the Protection of the Marine Environment from Land-Based Activities was adopted by the United Nations Environment Program on November 3, 1995. It calls for actions by signatory nations 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 foster conservation, protection and enhancement of the North American environment. In pursuing its mandate, the CEC is promoting a series of pilot projects in North America to implement the GPA, and has selected the Gulf of Maine as a candidate site. The CEC brought together a group of individuals with an interest in the Gulf of Maine and the GPA to develop and implement a suitable project. This group, the GPA Coalition on the Gulf of Maine, has formulated an action plan to this end. A 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.

This scoping paper has been prepared to assist participants by providing background information on land-based activities and related habitat issues and offering possible management objectives and actions for consideration. It provides an overview of land-based activities and their potential physical effects on marine habitats in the Gulf of Maine. However, the processes involved in the destruction or degradation of coastal habitats as a result of human activities are often subtle and complex. All around us, habitats are clearly being lost or degraded, but rarely is it possible to definitively identify a "smoking gun" responsible for the damage. In a 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 (such as hydrologic cycles, sediment dynamics and eutrophication) leading up to the degradation of habitat, and these are typically insidious, gradual and poorly understood. In many other situations a variety of confounding factors, such as natural ecosystem variations or cumulative/synergistic effects, serve to further obscure cause and effect relationships. Because of the difficulty in obtaining incontrovertible evidence to link many land-based activities with specific changes in habitats, this report adopts a two-pronged approach. First it looks at a range of land-based activities, and the possible environmental stresses they generate that could ultimately perturb marine habitats. Then it considers the principal habitat types and attempts to identify possible stresses that may potentially be associated with particular land-based activities. Finally, by assessing the situation from both perspectives, an activity-habitat matrix is developed to summarize the relative ecological importance of linkages between particular land-based activities and marine habitat impacts.

This report focuses primarily on those activities that may contribute to the physical destruction or modification of habitats; the pervasive effects of contaminants are dealt with elsewhere. The land-based activities discussed here are largely those identified in the Global Plan of Action, and are for convenience grouped into the following general categories:

Population growth and urbanization

population growth

urbanization

waste (sewage, marine debris)

Alterations to coastal morphology

diking

infilling

dredging, spoil disposal

groins, jetties, breakwaters

shoreline armoring

beach replenishment

Hydrologic alterations and tidal restrictions

dams

causeways, culverts, bridges

Resource harvesting

forestry

agriculture

aquaculture

intertidal harvesting

subtidal harvesting

mining, aggregate extraction

Energy production

tidal power

fossil/nuclear plants

Recreation and tourism

Within each category, the nature of each of the different activities and the scope of their occurrence in the Gulf region are briefly described. Any potential environmental perturbations or stresses that may be generated by the activities are also discussed.

This review limits itself to a manageable group of 12 very broad habitat types; namely, salt marsh, mudflat, sand beach/dune, cobble beach, rockweed bed, coastal islands, inshore benthic, inshore pelagic, eelgrass beds, kelp beds, offshore benthic and offshore pelagic. The general characteristics, ecological and economic importance, as well as the real and potential threats to ecological integrity are described for each of them.

We have made a particular effort to seek out the views of local communities regarding the importance of the environmental issues, because any efforts to solve the widespread problems must involve them, and must address their particular concerns. To gauge community perceptions about which habitats are being lost, degraded or at risk locally, and which land-based activities are deemed to be most environmentally threatening, we interviewed knowledgeable representatives from 48 different groups distributed widely around the Gulf. These included representatives of conservation, environmental, First Nations, fisher, industry and academic organizations. Complementary information was also extracted from a detailed compilation of information on 29 Gulf of Maine Estuaries being prepared by the Conservation Law Foundation/Island Institute and the Conservation Council of New Brunswick as part of the Restore America's Estuaries Program’s Gulf of Maine Estuaries Restoration Project (GOMERP). The information from both the interviews and GOMERP compilation provides an overview of community concerns regarding habitats at risk and human activities responsible. The ranking of habitats and land-based activities of concern are as follows: (the numbers indicate the percentage of times the concern was raised).

A potential impact matrix was then formulated, consisting of the ranked (top to bottom) land-based activities along one axis and the ranked (left to right) marine habitats along the other (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 information. 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 concern 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 involve major impacts were then regrouped in Table 2. Each activity was then assessed 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:

The following includes a synopsis of some of the concerns regarding each issue (see scoping paper for details and examples) as well as recommended management objectives and actions to address them:

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.

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.

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.

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.

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.

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.

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.

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.