18-20 September, 1995
Dartmouth College
Hanover, New Hampshire
convened by
Regional Association for Research on the Gulf of Maine
(under contract from the NOAA National Marine Fisheries Service)
RARGOM Report 95-1
December 19, 1995
To request a copy of the full report, contact the Regional Association for Research on the Gulf of Maine headquarters:
The Gulf of Maine is an internationally important economic region. Bordering the United States and Canada, the region is a resource of inestimable value: it supports commercially important species of fish and shellfish, aquaculture, tourism, and recreation. Its coastal areas provide for residences and economies serving 3.6 million persons. Located between 41 and 46 degrees N latitude, and 71 and 65 degrees E longitude, the Gulf of Maine and its contained physical system, consists of watersheds, estuaries, and embayments, coastal waters and predictable hydrographic features, as well as the water columns and basins of the central Gulf of Maine. Generally, large areas of the Gulf remain relatively pristine and healthy. Available data indicate, however, that the Gulf of Maine is increasingly being affected by anthropogenic stressors which have potentially synergistic and cumulative effects, as well as individual effects, not only in watersheds and estuaries, but in central areas of the Gulf.
One hundred fifty years ago, the region was characterized by robust fisheries, developing economies and regionally uncontaminated habitats. Currently, important segments of the populations face an economic crisis linked to the exploitation of available resources and local habitat degradation. Fisheries, introduction of contaminants of environmental concern from point and non- point sources, and habitat degradation and loss are dominant stressors in the inshore, and fisheries and habitat degradation in the offshore regions of the Gulf of Maine. The inshore region is also subject to natural stressors, as well, that may exacerbate the effect of anthropogenic stressors.
Continued population growth and associated urbanization and industrialization in the watersheds leading to estuaries, embayments, and coastal waters, will be the principal factors determining the well-being of these waters in the future. Recovery of degraded waters and rebuilding of fisheries, marine mammal populations, other protected species, and their food webs, will depend greatly on an increased knowledge of linkages which exist between the various aquatic systems such as exist in the watershed, estuaries and embayments, coastal waters, and the central portion of the Gulf of Maine. Likewise, the numerous linkages that exist between the habitats (and degree of impact on habitats), food chains, fish stocks, and marine mammals must be better understood than is the case today.
Because components of the Gulf of Maine ecosystem are poorly known or not understood sufficiently, a conservative or precautionary management approach must be followed, so that managers can avoid the risk of making decisions with harmful, and potentially irreversible impacts on the ecosystem. As we enter the next century, there is increasing need for effective stewardship of resources while further knowledge of the region is acquired. Future generations should inherit a region where the resources have been conserved and are available through sustainable productivity. The individual concerns and interests of various elements of society must not be the sole principal determining factors, but must become a part of regional planning for the resources.
The Gulf of Maine must be understood and managed as a total and not as a series of separate entities bordered or divided by arbitrary geopolitical boundaries, if it is to be ensured of a sustainable productivity. To have effective management of the aforementioned resources will require that there be "fused geopolitical management" of these various components of the Gulf of Maine ecosystem. Just as anthropogenic activities, and certain environmental changes result in "fractured linkages" between various components of the ecosystem, the present situation -- diffuse research and management attempts resulting from the legitimate concern of numerous government and non-government organizations -- prevents effective scientific management of the Gulf of Maine.
In the near future, existing organizational resources must be used in a cooperative, coordinated scheme to carry out needed research and management. Entities presently exist in the Gulf of Maine to conduct research, establish priorities for research and management, and conduct the necessary theoretical, field, and laboratory studies; these groups, given the resources, can provide the data and information essential to management.
The Gulf of Maine, its habitats and resources, and the various options for management and future legislation and regulation, must be described and promoted in educational institutions, and the media, so that the citizenry is fully informed and educated as to present and future conditions, especially in regard to the steps that must be taken to manage the overall system on an integrated geopolitical basis.
A scientific workshop was held from 18-20 September 1995 to assess the human-caused factors affecting the health and stability of the Gulf of Maine marine ecosystem and to identify research and management options to restore and/or maintain the environmental quality of the ecosystem. This report summarizes the working group deliberations on three topics: anthropogenic stressors, fisheries, and marine mammals/protected species. Full working group reports and plenary papers will be presented in the workshop proceedings, RARGOM Report 96-1 (scheduled for publication in Spring 1996).
* Over fishing and related impacts,
* Contaminant introduction, primarily in the near shore coastal zone (toxins, nutrients, and pathogens), but via atmospheric input as well,
* Physical alteration and loss of critical habitat especially for sensitive or key species (in riparian, coastal and offshore regions),
* The effects of human activities on endangered or threatened species such as right whales; (although these effects on endangered or threatened species may be of relatively minor significance to overall ecosystem dynamics, the effects on these populations are very important);
* Factors external to the Gulf of Maine which affect seasonally resident and resident populations (including atmospheric deposition, global warming, effects on migratory populations in other ecosystems or regions), and
* Decision-making practices which can best be characterized as based on local, site specific, short- term, crisis-oriented decision-making, need to be replaced by regional, long-term, information and risk based management.
Based on the aforementioned understandings that were developed during the workshop, the following were deemed to be overarching issues and needs relating to future research, management, and educational activity in the Gulf of Maine:
* Identify critical linkages between ecosystem components and subsystems and their sensitivity to cumulative and individual stressors. Significant advances have been made in understanding subsystems, but the ecosystem dynamics of the Gulf of Maine as a whole are poorly understood. A combination of field and modeling studies must be conducted at logistically feasible and manageable levels of effort.
* Use interdisciplinary research approaches, working to link cumulative and individual stressors of the system to their effects, (reflecting the strong gradient of anthropogenic stressors in the Gulf of Maine).
* Evaluate resilience (recovery from disturbance) of ecosystems and ecosystem components known to be affected by natural and anthropogenic stressors (response to multiple stressors) and establish predictable recovery(ies).
* Develop criteria to assess sensitivity of coastal embayments and estuaries from an interdisciplinary perspective of habitat change, contaminant introduction, fisheries harvesting, and physical and biological processes. Because embayments and estuaries are both directly or indirectly affected by anthropogenic activities in adjacent watersheds, linkages between any two such systems also need to be established.
* Seek cost-effective solutions through increased integration of rigorous scientific assessment of the problems and potential solutions. There are numerous examples (case studies, for instance ocean disposal and its cessation in the New York Bight apex), where management decisions have resulted in measurable improvement in environmental quality.
* Develop and implement integrated management strategies encompassing the key or sensitive components of both the Gulf of Maine per se and its watersheds, to avoid loss or degradation of key components, disruptions of linkages, and collapsed ecosystems, and avoid the need for costly remedial actions in the future.
* Strengthen existing (1) water quality criteria (and create sediment criteria for significant toxins), and (2) enforcement activities to protect marine habitats and resources in the Gulf of Maine.
* Use scientifically sound, cost-effective actions to restore and protect environmental quality. Given existing knowledge regarding physical, biological and chemical processes in the Gulf of Maine this will require a comprehensive regional approach for success, which is based on interagency, inter institutional, and international shared efforts and accountability.
* Adopt a precautionary approach in the face of uncertainty or insufficient information.
* Increase public educational efforts, recognizing that communication between all users of the Gulf of Maine region's resources is crucial to the establishment and operation of effective conservation and management measures.
* A Gulf-wide data and information directory is needed, and it must be nurtured, supported, and used on an international, interagency basis. Types of information important to informal decision-making need to be accessible for general use, and include: research activities being conducted, data being compiled and archived by different organizations, and how those datasets can be accessed and used.
The following section provides a brief analysis of the major factors affecting the overall health of the Gulf of Maine ecosystem and its key components and summarizes key ideas presented at the workshop for future activity in these areas. These thoughts emerged from the three working groups gathered at the workshop (Anthropogenic Stressors, Fisheries Harvesting, and Marine Mammals/Protected Species) and subsequent discussions held by the workshop organizers and reviewers.
Fisheries harvesting is the dominant stressor of exploited resources in the offshore region of the Gulf of Maine, resulting in changes in abundance and species composition of both targeted and non-targeted species.
Many of the fishery resources that support ocean fisheries in the Gulf of Maine region are at or near record low stock sizes and landings. A number of bottom-dwelling groundfish stocks (cod, haddock and yellowtail flounder) have been severely depleted due to years of overfishing under a variety of fishery management regimes. The reduced yields from the depleted stocks are causing serious economic and social repercussions in the Gulf of Maine/Georges Bank region. This situation has lead to gear conflicts between otter trawl and gill net fisheries; resource allocation controversies between inshore and offshore fishers and between the recreational and commercial users; and political jurisdictional issues between the state and federal governments in the United States and for transboundary stocks between the United States and Canada (especially in relation to the Hague Line on Georges Bank).
With the extension of United States jurisdiction to 200 nautical miles (Exclusive Economic Zone), over-exploited resources began to recover, and domestic fishing effort increased. Restrictive management programs, in place since the waning days of foreign fishing, were abandoned in the early 1980s. The New England Fishery Management Council initially retained the quota-based fishery management system it inherited from the earlier management schemes adopted by international convention, but eventually abandoned direct controls on fishing mortality in 1982. Since 1982, fishing mortality rates on groundfish resources have steadily increased, whereas harvest rates on principal pelagics (Atlantic mackerel and ocean herring) have continued to decline. Evidence from stock and recruitment data indicates that current harvest rates on most groundfish species are higher than those that would allow for replacement for the stock (recruitment overfishing--see further explanation below). Declines in spawning stocks and recruitment to the groundfish stocks in many cases are more severe than what occurred under distant- water fleet effort 20-30 years ago.
The term "overfishing" is used to describe conditions that result in sub optimal use of fishery resources, based on both biological and economic criteria. Recruitment overfishing results when the number of fish that are spawning diminishes to the extent that reproduction is inhibited in the population, resulting in an overall decline in the number of fish available for harvesting. Growth overfishing is based upon economic criteria, in which lower than maximum yields are obtained for a given number of participants in that component of the fishing industry. Many of the New England groundfish stocks are considered to exhibit recruitment overfishing. The rebuilding of the many of the groundfish populations will require a significant period of time with low fishing mortality rates, with some stocks rebounding relatively quickly (5 years) whereas others may take a decade or more. Monitoring the recovery will require continued reliance on research vessel surveys (fishery-independent stocks assessments) and "sentinel" fisheries in which commercial vessels target specific stocks at a low harvesting level in order to supplement the research survey information. Rebuilding these depleted stocks will also require a shift in the management approach with an emphasis on protecting the resource, rather than the process being driven by short-term economic and sociological concerns.
In addition to the direct effects of over harvesting, there are many indirect effects of fish harvesting, such as bycatch of non-target species, impacts of trawling on the soft bottom benthic prey of groundfish, and increase in other fish species, which has altered the ecosystem on which the commercial groundfish depend. The increased abundance of pelagic predators and elasmobranch predators as a consequence of fisheries harvesting of the targeted groundfish species will complicate the recovery of species in the New England multispecies groundfish plan, even if fishing mortality is reduced. The groundfish also compete with marine mammals and seabirds for prey species, so there will be conflicts in the use of prey species at the base of the food web.
Indirect ecosystem effects, as well as direct effects of fishing activities on target and non-target resources, must be considered in the plans to rebuild the depleted groundfish populations. An ecosystem-based management approach must be adopted to optimize ecosystem yield, rather than economic yield, with the fishery resource yield to humans based on an understanding of the limits of ecosystem productivity and recognition of the non-consumptive as well as consumptive values of key ecosystem components.
Overfishing was judged as the major anthropogenic stressor in the offshore waters of the Gulf of Maine. It should be recognized, however, that for species which use coastal waters/estuaries for either spawning or nursery areas, contaminants and habitat degradation will influence the success in rebuilding the fish species used by man. Such species would include winter flounder, striped bass, river and blueback herring, lobsters, bay scallops, soft shell clams, hard shell clams and urchins. Impacts of overfishing are also seen in marine mammals, seabirds and turtles and other forms no longer subject to direct harvesting. Even though the emphasis in this report concerns the biological condition of the stocks, the overfishing issue has components that include the behavior of fishers in a declining socioeconomic scenario; the number, size and composition of fishing fleets; the lack of selectivity of otter trawls, and the market demand for under-utilized species.
* Determine the food chain interactions between abundant and depleted species in order to develop appropriate recovery plans for groundfish,
* Continue and expand sea sampling programs on fishing boats at sea to estimate bycatch mortality of nontarget species and harvest rates for targeted species. This activity should be augmented with a feedback mechanism so that fishers can modify their fishing methods and, in addition, this information should be made more readily available to researchers and concerned Non-governmental Organization constituents (except for proprietary information),
* Determine/quantify the relationship between gear type and fishing capacity/power,
* Improve selectivity (and reduce bycatch) of mobile fishing gears,
* Determine the impacts of mobile fishing gear on the soft bottom benthic organisms that are prey for ground fish, and
* Establish the socioeconomic factors affecting excess fishing capacity.
* Develop and implement strategies to reduce the excess fishing capacity within the region,
* Establish and employ a regional planning approach to deal with transboundary political jurisdictional problems in managing fisheries (state/federal governments and U.S./Canada),
* Implement adaptive management plans, with a risk adverse approach (to account for uncertainty or insufficient knowledge) to rebuild the multispecies groundfish complex within the Gulf of Maine/Georges Bank ecosystem,
* Enhance communication between scientists, managers, and the fishing industry (commercial and recreational) on the need to rebuild stocks and the measures required to achieve this goal,
* Educate fishers and the public about long-term benefits associated with rebuilding ground fish stocks,
* Develop markets for highly abundant species (mackerel and herring) and elasmobranch predators (skates and dogfish) to provide alternatives harvesting opportunities for fishers.
There are gradients of contaminants of environmental concern in the water column and sediments of the Gulf of Maine nearshore zone reflecting known sources (related to human population density) and physical circulation (transport) patterns. However, the linkages between the cumulative stressors of anthropogenic and natural processes on ecosystem functioning are poorly understood in the Gulf of Maine, and other comparable water bodies.
Contaminants of environmental concern, generally organic and inorganic compounds either produced or mobilized by mankind, have been inadvertently or intentionally released to the marine environment where they can, if exceeding threshold concentrations, have deleterious effects on the viability of component species of ecosystem. At present, most threshold concentrations are not well documented. The release of such contaminants in the Gulf of Maine have resulted in readily observable ecosystem level effects, usually in the vicinity of the major urban areas along the coastline. They include observations of highly contaminated sediments with respect to both metals and organic toxic compounds, high incidence of neoplasia in winter flounder and severe degradation of benthic habitat. Most of the impacts can be related to the discharge of sewage effluent and contaminated runoff from urban areas, usually in nearshore coastal embayments with restricted circulation.
Watersheds draining into the Gulf of Maine that are densely populated and/or heavily industrialized are also degraded with respect to both water and sediment quality. Discharges of rivers draining such areas are significant sources of contaminants to the Gulf of Maine and, as development proceeds into the 21st Century, are expected to become an even more important source of a variety of stressors, primarily in the near-shore zone, unless properly controlled. A considerable wealth of knowledge has been acquired on acute toxic effects as well as environmental levels present in mobile and sentinel species, or species representatives of several trophic levels, for certain groups of contaminants of environmental concern. These include metals (mercury, lead, and cadmium), organometals (methyl mercury and the butyltins), organochlorines (polychlorinated biphenyls (PCBs), chlorinated hydrocarbons and pesticides), and polyaromatic hydrocarbons (PAHs), which have been monitored in the sediment, mussels, fish (livers), marine mammals (blubber), and birds (eggs) from the Gulf of Maine. For example, metal concentrations in mussels and lobsters from the more polluted waters near Boston have been observed to approach levels considered to be unfit for human consumption. These levels, however, generally are not held to be necessarily deleterious to the health of the organisms themselves.
Organochlorines are known to bioaccumulate in the marine food web such that whales are reported to contain concentrations 100 times found in fish, whereas fish in turn contain concentrations 1,000 times those in plankton, and plankton contain concentrations 1,000 times that in seawater. The problem of organochlorine contamination is judged a global problem, resulting from atmospheric transport and deposition to the surfaces of lakes, coastal and ocean waters, as well as locally where much higher concentrations have been identified in sediments, mussels, and other organisms in waters neighboring human population centers. Both global and local sources of organochlorines have resulted in the accumulation of these compounds in the food chain. A similar set of observations have been made for mercury and lead as well. Regulations restricting organochlorine use were instituted in the late 1960s (e.g. DDT) and 1970s (PCBs) and have, for example, resulted in marked reductions in recently measured concentrations of these compounds in the harbor porpoise. The scientific community is continually identifying new contaminants of concern, for example, in the last decade, the presence of highly toxic dioxin in pulp mill effluents. However, the presence of these compounds in a recent survey of the mussel population near the mouth of the St. John River was not detected by the Gulfwatch (a Gulf of Maine Council monitoring program). The most urgent need of the global scientific community is to understand the long-term orchronic effects of each category of contaminant on both mobile and sentinel species. This knowledge must be expanded to include the cumulative effects of multiple contaminants on key species. Finally, an active vigil is required to identify, evaluate and quantify newly developed toxic compounds.
High densities (blooms) of certain phytoplankton species commonly occur in the marine environment. Some bloom species produce toxins, for example, saxitoxin causing paralytic shellfish poisoning (PSP) and domoic acid causing amnesic shellfish poisoning (ASP), that can be accumulated in higher trophic level species, particularly the shellfish, thus creating a potential danger to humans and marine mammals that may ingest them. To avoid human health problems, shellfish beds are often closed, resulting in the loss of harvestable resources. The planktonic species responsible for toxic and nuisance blooms are known. Blooms of these species occur primarily in the coastal waters throughout the Gulf of Maine, but have influenced offshore areas, including Georges Bank. The conditions or causes that trigger bloom events are not well understood, although anthropogenic introduction of contaminants of environmental concern such as nutrients and/or metals such as copper, iron, and lead is believed to be a possible contributing factor. While toxic events are known to have occurred throughout recorded history, their frequency has increased markedly in recent decades. There is evidence that the occurrence of red tide blooms in the western Gulf of Maine are influenced by "seed populations" formed in the vicinity of Penobscot Bay and transported to the southwest along the coast by coastal currents.
* Identify and quantify the major sources of contaminants of environmental concern to the Gulf of Maine and its key biota, its estuaries and watersheds, and the relationship between land-use patterns and source strength of these contaminants.
* Identify those embayments and estuaries and biota that are most sensitive to the introduction of contaminants by considering their physical circulation patterns and contemporary and projected source loadings.
* Determine patterns of transport of contaminants on a region-wide basis to avoid unexpected and deleterious accumulation and bioaccumulation of contaminants in sensitive regions and species of the Gulf of Maine.
* Develop methods to assess better the individual and cumulative effects of multiple stressors (physical, chemical and biological; both anthropogenic and natural) on the key ecosystem components and the ecosystem dynamics in the Gulf of Maine.
* Establish the factors that trigger nuisance algae bloom events, particularly the extent to which nutrient and other contaminant loading in coastal waters contributes to the occurrence of such events.
* Synthesize available data and, if necessary, document the current state of eutrophication and contamination of Gulf of Maine nearshore waters and sediments caused by both point and non-point sources.
* Establish or improve on present data base management systems for syntheses and integration of data and information for making decisions about management strategies and regulations to control the introduction of contaminants of environmental concern (nutrients, metals, organics and pathogens).
* Design, develop and implement appropriate regional as well as local cost-effective management and control strategies and regulations, with emphasis on source reduction and/or pretreatment as well as appropriate land-use planning to contain the introduction of contaminants of environmental concern and insure the cumulative effect of contaminant fluxes do not exceed levels at which the individual component of the ecosystem and human health effects are observed.
* Design and implement a comprehensive monitoring program of estuarine and nearshore coastal waters and representative biota, to identify and track the magnitude and location of eutrophication as well as the accumulation of contaminants of environmental concern.
* Continue dockside monitoring of shellfish for contaminants to protect human health and insure product safety. Other management recommendations will rely on increased understanding of the cause of bloom events.
A large percentage of the human population in Maine, New Hampshire, and Massachusetts as well as the Canadian Maritimes is located within the watersheds of the Gulf of Maine estuaries. Human activities have influenced estuarine ecology through changes in hydrology and physical habitat alteration.
Hydrologic changes in watersheds and estuaries include: diversion of freshwater for municipal and agricultural purposes; damming of freshwater flow for energy and flood control; restriction of tidal flows via roads, causeways and fill; and changes in quantity and quality of surface water runoff from shoreline development. Physical alteration of habitats is primarily related to dredging and filling activities and erosion of sand barriers resulting from hard stabilization (e.g., seawalls and jetties).
Hydrologic modifications have led to loss of estuarine habitat because of changes in discharge, salinity regimes and sediment transport. For example, wading bird feeding habitat in the Bay of Fundy was greatly reduced over a century ago through freshwater diversion and other of man's activities. The delivery of freshwater, sediments, and contaminants has been increased by shoreline development. Eelgrass habitats become more susceptible to wasting disease with reduced freshwater inputs. Salt marshes degrade and subside due to partial or total restriction of tidal flow. Invasive plants out-compete natural marsh vegetation. Structures that modify hydrology also impede fish passage and have led to a near demise of anadromous fish populations. Also, dredging and hard stabilization alters flow patterns and sediment distribution and transport, directly affecting soft sediment habitats and contributing to erosion of barrier beaches and salt marshes.
Habitat refers to the biological, chemical, and physical/geological characteristics required by a species to survive and thrive in the aquatic environment. In nearshore wetland, subtidal seagrass, beaches, mudflat, hard substrate intertidal/subtidal regions, and soft sediment subtidal systems, the physical/geological nature of the environment plays a crucial role in determining habitat features. In open water column environments the chemical characteristics and physical water mass movements determine the temporally varying nature of the habitat features. Superimposed upon these habitat features are biological interactions, such as competition and predation, that help determine the success of a species in time and space. Habitat alteration can be due either to habitat loss (quantitative) or habitat degradation (qualitative). For many species in the Gulf of Maine, critical life history requirements are poorly known, so that we cannot specify what their essential habitat requirements might be. We do know that habitat changes in other coastal wetland regions, such as the Chesapeake Bay, have led to dramatic declines in many species that support important fisheries.
In many instances, the seasonal distribution of a species is used to infer its habitat characteristics. This approach ignores the fact that for many intertidal organisms physical factors define the upper limits of an organisms distribution, while biological factors often limit the lower limits of distribution. Biological competition and physical stress from desiccation/salinity/temperature can interact, forcing an organism to occupy a distribution that is non-optimum for that species. Even though the emphasis in this discussion will be on the forcing functions of hydrologic alteration, habitat loss/change, and habitat degradation, it should be borne in mind that there is a biological component to these interactions that may be critical. The critical qualitative characteristics that cause an organism to choose and occupy a given habitat are poorly understood and require sufficient knowledge of the species' natural history characteristics.
Hydrological alterations can include the impacts of potential sea level rise; changes in flow patterns due to channelization, construction of seawalls and jetties, or dredging activities; altered drainage patterns in coastal wetlands; or secondary impacts resulting from sediment erosion/deposition. The altered hydrology not only causes a direct physical impact, but it can change the transport of pelagic larvae of marine species and alter sediments that support wetland plant species. For example, inundation of wetland areas can cause water logging in the soils and the buildup of hydrogen sulfide, toxic to many plants. Loss of barrier beaches can result in erosion of the soil that supports many wetland plants. As sea level has risen many barrier beach/wetland complexes are already retreating landward, where they encounter the fixed barrier of human development which restricts their migration, while at the same time removing the buffers that protected the human habitations from flooding and storm events. Human build-out in coastal areas has also provided impetus for the construction of seawalls, jetties, rip/rap construction on coastal dunes, and other physical structures. Those structures have altered the flow of water with its accompanying effects on sediment erosion/deposition critical to maintaining coastal habitats in the face of sea level rise.
Human construction activities have greatly changed the pattern of sediment input to the marine environment with its accompanying load of non-point contaminants (especially nutrients). Many benthic animal populations are restricted to given types of sediments and increased sediment input can change the essential habitat features for these species. For example, juvenile lobsters occupy burrows under rock and rubble regions at the subtidal/ intertidal interface, with these habitats being lost if excessive sedimentation occurs. Many benthic species are also important elements in the diets of finfish species. Sediment input reduces the oxygen available in the water column that is used by animals to ventilate and respire. The sediment input also can result in nutrient enrichment which stimulates algal blooms in the water column or macroalgal growth in benthic environments. Dying algal blooms may use up residual oxygen in the water column resulting in fish kills. Proliferation of macroalgae can displace eelgrass beds which are important habitats for bay scallops and juvenile winter flounder and tautog.
Alteration of benthic habitats by mobile fishing gear is the primary stressor affecting offshore regions of the Gulf of Maine. The effect of repeated disturbances onthe production and diversity of benthic ecosystems is poorly understood. Anthropogenic activities in the nearshore coastal waters and estuaries are the major stressors, and include: urbanization, aquaculture operations, impacts on the benthos from mobile fishing gear, drainage of wetlands, armoring of the coast to protect human habitation, construction of dams in coastal rivers, and gravel mining/oil and gas development. Because many Gulf of Maine fish species depend on estuarine habitats during some portion of their life cycle, these activities have a considerable potential to influence coastal fisheries. The lack of data, as well as the lack of access to existing data via an easily accessible, user friendly database associated with a geographic information system (GIS) for the Gulf of Maine region inhibits attempts to adequately characterize the anthropogenic stressors in space and time, and to delineate their individual and cumulative contributions to habitat alteration.
* Conduct a Gulf-wide assessment of sensitive species and key habitat loss and degradation due to hydrologic alteration, which would support improved management of coastal habitats. Such an assessment should include:
* Assess and document the extent and impact of ever increasing urbanization and resulting land use change on adjacent living marine and other aquatic resources.
* Assess the multiple impacts of the growing aquaculture industry and determine if aquaculture operations are having a significant negative impact on the biota and stocks of fish and wildlife using nearshore habitats.
* Integrate knowledge of physical habitat alteration, contaminant sources and other stresses in order to understand better the relative susceptibility of various estuaries and embayments to multiple anthropogenic impacts.
* Determine the impacts of inshore habitat loss and alteration on inshore, nearshore, and offshore living marine resources.
* Ascertain the impacts of mobile fishing gear on offshore benthic ecosystems and the capacity of those ecosystems for recovery after repeated disturbance.
* Manage more carefully the amount and timing of freshwater diversion, control of tide gates, design of culverts and causeways (or replacement by bridges), dredging and filling, and aggregate mining to maintain or restore ecosystem function to estuaries,
* Establish shoreline buffer zones and schemes to reduce delivery of sediments, runoff, and contaminants from non-point sources,
* Establish strict controls on coastal aquaculture to avoid contamination of seafloors and the surrounding water columns, and
* Establish stronger regulations to protect bird roosting, feeding, and nesting habitats.
* Articulate management goals, so that scientists can define the critical system parameters to be monitored in order to establish habitat alteration is being improved as a result of management actions.
* Interact more effectively with the public to relate management goals to public concerns, plus explain the benefits to be accrued from management action, revealing the full costs to be borne by private citizen groups.
Most populations of marine mammals in the Gulf of Maine have been severely reduced by human activities. For example, most of the large baleen whales were over harvested in previous centuries and continue to be affected by human activities today. In general, our knowledge of the natural history and habitat requirements of the protected species is not fully sufficient to assess all the effects of individual and cumulative stressors on these ecosystem components in the Gulf of Maine.
Although marine mammals, sea turtles, and birds are no longer hunted for commercial purposes, human-caused mortality and injury continue to pose serious threats to such species and populations. Many species of birds, as well as marine mammals and turtles, are caught and killed in both actions and in lost and discarded fishing gear. Such incidental mortality, combined with mortality from ship strikes, may be preventing or impairing recovery of endangered right and humpback whales. Incidental take in fisheries, particularly gillnet fisheries, may be threatening the continued existence of the harbor porpoise population in the Gulf and adjacent areas. Anthropogenic contaminants, toxins from algal blooms, and repeated disturbance by bird and whale watchers, recreational hikers and boaters, etc. may also be affecting some species adversely.
Little is known about the food and other habitat requirements, habitat-use patterns or essential habitats of marine mammals, seabirds, and sea turtles that inhabit the Gulf of Maine seasonally or throughout the year. Therefore, while it is reasonable to assume that some critical habitats and habitat components are being affected adversely by anthropogenic contaminants and some land-use fishing practices, available information is insufficient to judge the significance of the threats are how best to avoid or mitigate them.
Information on the population status and trends data is relatively good for some protected marine mammal species (northern right whales and humpback whales) and shore birds (piping plovers and least terns), but is fragmentary for many species of sea turtles, sea birds, and other cetaceans that occur in the Gulf of Maine. We do have reliable population and trend data on at least two species of baleen whales; the humpback whale is believed to be making a recovery, but the northern right whale population remains one of the most endangered species, with only 300 or so animals remaining in the Northwest Atlantic. Harvesting of this population has been prohibited since the 1930s, yet the population has grown little, if at all, since then. The cause(s) of lack of population growth in right whales are not fully understood, but ship strikes within and outside the Gulf of Maine Ecosystem are believed to have an important effect on their distribution and abundance.
As is the case with many protected species, small cetaceans are vulnerable to several human-caused stressors, the most important being incidental mortality in commercial fisheries. Large numbers of harbor porpoises are killed in gillnet fisheries in both United States and Canadian waters, with recent deaths averaging over 1,850 per year. The National Marine Fisheries Service, in its 1993 Proposed Rule (58 FR 3108), reported that this level of incidental take is unsustainable.
Two pinniped species, the harbor and grey seals, are of concern because they are increasing in abundance and range, and face increasing potential conflict with mariculture and commercial fishing endeavors.
There are four categories of bird species that have protected status in the Gulf of Maine: colonial breeding birds, raptors, shorebirds, and non-breeding pelagic birds. Human activities such as coastal development, habitat degradation and destruction, disturbance, and the generation of organochlorine contaminants threaten these populations. Human-created waste habitats (dumps) have also spurred explosive population growth of gulls, which then displace and prey on other seabirds.
The leatherback sea turtle, a summer visitor to the Gulf of Maine, is the only threatened marine reptilian species found in this region. The primary known threats to this species in the Gulf of Maine are entanglement in commercial fishing gear, ship strikes, and ingestion of marine debris. Other human activities, primarily outside the region, pose more critical threats to these animals, and include: direct exploitation, harvesting of eggs, and nesting disturbance.
Two threatened fish species, the Atlantic salmon and the shortnose sturgeon, have been afforded protection under the Endangered Species Act because of past over-exploitation, degradation of estuarine habitats and loss of spawning habitat.
Our current knowledge is not adequate to describe the full range of effects of individual human activities, or the cumulative impact of these activities, on protected populations. We have outlined several categories of threats in this report: direct mortality, commercial harvesting of prey species, habitat loss and degradation, and environmental contaminants. While the impacts of these stressors on protected populations are of critical concern from the standpoint of maintenance of biodiversity and the conservation of endangered species, the extent to which the status of these populations pose an overall threat to ecosystem dynamics of the Gulf of Maine as a whole is probably quite low. However, the demise of endangered species populations would clearly represent a compromise to overall ecosystem health. To conserve effectively these species and their ecosystem, managers and researchers, and those who derive their income from the region's resources, need to integrate more fully their daily responsibilities and work toward a shared stewardship goal, thus reflecting the interrelated nature of the Gulf of Maine system of which we are members.
* Obtain better information on the natural history and demography of marine mammals and their ecological relationships with other components of the Gulf of Maine ecosystem.
* Determine when and where right and humpback whales are vulnerable to ship strikes and entanglement in fishing gear so that better preventative measures and management protocols can be formulated and implemented.
* Determine (1) the size, productivity, and discreteness of harbor porpoises and other population(s) affected by incidental mortality in commercial fisheries, and (2) the level, age, sex composition, and temporal and spatial distribution of incidental mortality of the affected population(s).
* Determine effective means for reducing the incidental mortality of harbor porpoises in gillnets by examining (1) whether time/area closures will ensure that the level of incidental take does not reduce the population or maintain it below its maximum net productivity level and (2) whether acoustic devices attached to nets could reduce incidental mortality while having no impact or other species.
* Determine the feeding patterns, food preferences, and principal feeding areas of harbor seals and gray seals to judge how, and to what extent, growing populations of these pinniped species may affect commercially important fish stocks.
* Determine the effects of noise pollution from vessel traffic and other sources on marine mammals and other protected species.
* Determine what, how, and at what levels anthropogenic contaminants may affect the survival and productivity of birds, particularly those that feed in estuarine and nearshore areas.
* Obtain accurate estimates of the species and numbers of birds being killed or injured incidental to commercial fisheries, and by entanglement in and ingestion of marine debris in the Gulf of Maine;
* Determine the feeding habits, dietary requirements, principal prey species, and principal feeding area of the various bird species that are part of the Gulf of Maine ecosystem. Fisheries managers should take into account the food requirements and feeding ranges (locations) of seabirds when developing fishery management plans for important seabird prey species.
* Detect and determine the likely cause(s) of future bird population changes and trends.
* Determine the movement patterns, feeding habits and food requirements of the leatherback turtle to understand whether any part of the Gulf of Maine is critical to the survival and recovery of the species.
* Develop and implement a "Take-Reduction Plan" for harbor porpoises as soon as possible.
* Expand efforts to locate and free right whales from entanglement in fish gear and reduce ship strikes.
* Conserve and protect important on-land nesting sties, roosting sites, and adjacent buffer areas.
* Increase public awareness of the causes and possible consequences of disturbance of birds in nesting, roosting, and feeding areas.
* Eliminate garbage dumps and other artificial sources of food responsible for the increases in gull populations in areas where gulls are displacing or otherwise impacting on other bird populations.
* Continue and expand seabird restoration programs (for species such as roseate terns, Atlantic puffins, and garnets), to increase their distribution to historic levels and decrease their vulnerability.
This workshop was mandated by Sec. 20, "Marine Ecosystem Protection", of the Marine Mammals Protection Act Amendments of 1994. The relevant portions are reproduced below:
"No later than one year after the date of enactment of the Marine Mammal Protection Act Amendments of 1994, the Secretary of Commerce shall convene a regional workshop for the Gulf of Maine to assess human-caused factors affecting the health and stability of that marine ecosystem, of which marine mammals are a part. The workshop shall be conducted in consultation with the Marine Mammal Commission, the adjacent coastal States, individuals with expertise in marine mammal biology and ecology, representatives from environmental organizations, the fishing industry, and other appropriate persons. The goal of the workshop shall be to identify such factors, and to recommend a program of research and management to restore or maintain that marine ecosystem and its key components that:
(A) protects and encourages marine mammals to develop to the greatest extent feasible commensurate with sound policies of resource management;
(B) has as the primary management objective the maintenance of the health and stability of the marine ecosystems;
(C) ensures the fullest possible range of management options for future generations; and
(D) permits non wasteful, environmentally sound development of renewable and nonrenewable resources.
"On or before December 31, 1995, the Secretary of Commerce shall submit to the Committee on Merchant Marine Fisheries of the House of Representatives and the Committee on Commerce, Science and Transportation of the Senate a report containing the results of the workshop under this subsection, proposed regulatory or research actions, and recommended legislative action."
A scientific workshop was convened by the Regional Association for Research on the Gulf of Maine (RARGOM) at its headquarters at Dartmouth College from 18-20 September, 1995. The goals of this regional workshop were:
a) to assess human-caused factors affecting the health and stability of the Gulf of Maine marine ecosystem; and
b) to identify research & management options to restore and/or maintain the environmental quality of the ecosystem.
Workshop participants discussed the status of key ecosystem components that characterize the Gulf of Maine, from three perspectives: Anthropogenic Impacts/Natural Environment, Fisheries Harvesting, and Marine Mammal/Protected Species. In each category, the state of knowledge was surveyed; individual stressors (direct and indirect) were identified, and their cumulative impacts described. The themes of habitat, biodiversity, and ecosystem function were emphasized throughout. The workshop focused on problem identification and on the pros and cons of possible alternative research and management strategies.
Invited participants were selected from the research community, resource users, and state/federal managers with expertise in the fields of marine biology, ecology, and the various branches of oceanography. Participation by the broader public was encouraged through initial plenary presentations.
Day 1 was devoted to the plenary session conducted by scientific experts from within and beyond the Gulf of Maine region. Topics that addressed facets of the three workshop themes were used to structure these plenaries. This session was open to a wide audience and provided time for public participation through discussion following the individual speakers and also during a public input session during the afternoon. Total attendance was 63 people.
Day 2 was devoted to in-depth review and analysis of historical and contemporary data and information by pre-assigned working groups in the three categories. The objective of the second day was to produce detailed outlined working documents which were used to draft the workshop proceedings. Each working group was asked to consider three primary questions as they related to its topic: (1) What is the nature of the problem? (2) What is the status of knowledge? and (3) What are the options for future research and management activity? Each group was also charged with prioritizing research needs by their degree of urgency and availability of relevant information.
Day 3 was spent distilling the working group discussions, developing broad report outlines, and synthesizing ideas forthcoming from Days 1 and 2.
This report is a summary of the major conclusions and research and management options from each working group, in response to each of these questions. The reader is referred to the three working group reports in the workshop proceedings (RARGOM Report 96-1, in preparation) for more detailed summaries of their deliberations.
This workshop was conceived and planned under the auspices of the Regional Association for Research on the Gulf of Maine, and hosted at Dartmouth College. The National Oceanic and Atmospheric Administration funded (under Grant #40ENNF500226) the workshop: its planning, costs incurred during the event, and the preparation and printing of the reports . Some participant travel costs were also supported directly by the National Marine Fisheries Service.
Proceedings to be referenced as:
Foreword
1. Executive Summary
2. Plenary Papers
Appendix A : "Health of the Gulf of Maine Ecosystem" White Paper by Kevin Chu
Appendix B: Workshop Agenda
Appendix C: Participants
Appendix D: Bibliography
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