Priority Ocean Areas for Protection in the Mid-Atlantic
Findings of NRDC's Marine Habitat Workshop
The offshore waters of the mid-Atlantic -- from Georges Bank, to the North Carolina coast -- are home to extraordinary submarine canyons, fragile cold-water corals, productive fish and crustacean habitat, and migratory mammal and sea turtle species. The United States Exclusive Economic Zone (EEZ) for the mid-Atlantic extends from 3 to 200 nautical miles offshore. Within the mid-Atlantic EEZ, federal agencies continually make management decisions that have important ecological and economic impacts. These decisions involve ocean dumping of dredged material, sand and gravel mining, oil and gas development, shipping, fishing, and other activities. Increasingly, attention has been focused on the benefits of protecting some areas of the ocean from potentially harmful activities.
Appreciating the need for better understanding, management, and protection of marine resources in general and in the mid-Atlantic region in particular, the Natural Resources Defense Council (NRDC) organized a workshop designed to bring scientists together to identify specific ocean areas that are priorities for protection in this region. NRDC mapped polygons reflecting each scientist’s recommended priority ocean areas for protection. Overlaying the polygons revealed multiple nominations for five ocean areas comprising some 19.4 percent of the study area: the nine submarine canyons; the offshore waters near Cape Hatteras, North Carolina; tilefish habitat between Cape May, New Jersey, and Cape Cod, Massachusetts; a 35-kilometer (18.9-nautical mile) corridor of nearshore waters extending along the study area; and a band along the continental shelf break encompassing the upper slope. In addition to these five areas of significant overlap, other areas were identified as priorities for protection by one or more scientists.
NRDC has a long history of working on coastal and ocean issues both nationally and within this region. The information generated at this workshop, NRDC believes, will be of value to policymakers weighing the impact of their decisions on ocean resources, and to the general public, which may well be unaware of the rich and varied living marine resources in the region.
ABOUT THE MID-ATLANTIC
The ocean waters in the mid-Atlantic region experience the most extreme temperature variation of any marine body in the world. Partly because of its range of climate and variety of physical features, the mid-Atlantic supports highly diverse populations of fish, whales, sea turtles, crustaceans, and other invertebrates. Sea turtle populations include leatherbacks, loggerheads, and Kemp’s ridleys. Cetacean species include right, sperm, beaked, pilot, sei, and fin whales, and common, Rizzo’s, bottlenose, striped, and spotted dolphins. Exposed substrate in the canyons supports corals, sponges, and anemones.
In addition to its inherent biological significance, the mid-Atlantic supports a number of valuable commercial and recreational fisheries including those for flounder (including summer, winter, and witch), sea bass, herring, monkfish, mackerel, blue-fish, lobsters, horseshoe crabs, scallops, ocean quahogs, surf clams, tilefish, and squid.
The continental shelf within the mid-Atlantic region extends from the shoreline to the continental slope at roughly the 200-meter isobath. Besides water depth, several physical influences are thought to impact biological habitat in this region. First, sediment texture: the shelf is primarily composed of sand, with isolated patches of coarse-grained gravel and fine-grained silt and mud deposits. Second, seafloor variability: the main physiographic feature within the mid-Atlantic is the Hudson Shelf Valley and Canyon (see the map on page 4), extending from the inner-continental shelf, at about the 40-meter isobath, onto the continental slope. The Hudson Shelf Valley and Canyon are primarily composed of fine-grained sediments (fine sand, silt, and clay). Other significant physiographic features include several other major canyons, at least one seamount, and the unique oceanography and geology off Cape Hatteras.
Water temperature, both seasonal changes and temperature fronts, is considered a third potential factor influencing biological habitat. Bottom temperatures fluctuate across the shelf, with the highest variation near the shore and the most stable bottom temperatures occurring along the continental shelf break. The waters along the shelf break form a noticeable temperature front, even on the surface. Currents represent a fourth, related, factor: the current flowing southwest from Georges Bank tempers seasonal changes in the mid-shelf waters.
ABOUT THE WORKSHOP
NRDC invited 15 leading marine scientists (see page 56), drawn principally from academia and government, who are known for their expertise concerning marine mammals, fish, sea turtles, and invertebrates, to attend a one-and-a-half-day working conference, held on September 26–27, 2000, at the NRDC headquarters in New York City. It is important to note that, despite the wealth of knowledge and expertise of those who participated, there were certain gaps in expertise, including gaps with respect to lobsters and crabs and some fish species, such as bluefish and striped bass.
Each scientist recommended specific areas (delineated on a map and referred to as polygons in this report) as meriting protection, provided a rationale for each polygon, and supplied scientific references to support his or her recommendation. Environmental Systems Research Institute ArcView GIS (Geographical Information Systems) software was used during the workshop to display and refine those polygons on a projected map. While the workshop did not call for a consensus of viewpoints, common criteria for protection did evolve, and common or overlapping polygons recommended by more than one participant and/or for more than one reason were identified.
ABOUT THIS REPORT
The primary purpose of this report is to summarize the results of the scientific workshop and make this information available to policymakers and the public for use in decisions affecting marine species and habitat in federal waters of the mid-Atlantic. To this end, NRDC has produced maps reflecting the priority areas of each of the participants, with an accompanying description of why these areas are important, references supporting the designation of each area, and maps indicating where the priority areas converge. It must be understood, however, that these maps are limited by a number of factors.
First, any scientist, even one completely versed in the existing literature on a particular subject, can only speak to what he or she knows about the ocean. As many participants pointed out, there is much that is unknown about the ocean, especially in places where fishing or other human activity has not sparked inquiry. To identify areas that are priorities for protection does not suggest that other areas would not be deserving of protection if more were known.
Second, the discussion at the workshop was limited to geographic and legislative boundaries that do not necessarily reflect ecological realities. NRDC originally defined the area for discussion as extending from Long Island, New York, to Cape Hatteras, North Carolina, because this area is considered a region in at least two important contexts: for fishery management and for oil and gas leasing purposes. NRDC subsequently extended the area south, since some participants observed that the area south of Cape Hatteras is a transitional area in terms of north-south migrations and supports an extraordinarily diverse suite of marine animals. Also, we decided to focus on federal waters because there is generally less understanding about the important role played by offshore waters in supporting marine life, and because decisions across this entire area come directly under federal management. Many participants, however, noted that there was no scientific basis for identifying polygons starting at the 3-mile boundary and so recommended areas for protection right into the coast and even into certain bays and sounds. This was so noted in the description of the areas, but the maps themselves identify important marine habitat only in federal waters. Plus, since the tip of Long Island is nearly parallel with the islands around Cape Cod, many scientists mentioned Cape Cod as the northernmost point of their recommendations, especially for migratory species.
Third, the workshop did not seek any kind of consensus-based ranking of priority areas for protection. Participants were given the opportunity to review and revise their own maps but were not expected to agree with the maps of other participants.
Fourth and finally, while some specific threats to marine life were identified, the workshop did not comprehensively address threats. Nor did the workshop make recommendations as to how these areas should be managed. Those decisions will involve a much more diverse group of interests as part of a broader policy debate. The purpose of this report is to begin to establish the scientific basis for such decisions in the future.
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