Kuujjuaq

6 9.1 Happy Valley-Goose Bay

St John’s

9.2 7

Gaspé Cape Breton

Québec Saint John Halifax

Portland 9

Boston Providence

New York 8 9.1 9.2

Washington, DC Dover

Norfolk

Jacksonville 10 11 0 100 200 400 km 9. Northern Gulf Stream Transition

Level II seafloor geomorphological regions include: 9.1 Northern Gulf Stream Transition Slope 9.2 Northern Gulf Stream Transition Plain

No Level III coastal regions are found in this region.

Regional Overview Stream-influenced Atlantic water and steep bathymetry, extend- The Northern Gulf Stream Transition Region—a region of open ing from 200 m at the shelf break to nearly 4,500 m at the abyssal ocean in North Atlantic lying adjacent to and affected by the plain. At the western edge of the region is the locus of the Canyon Gulf Stream10 to the east, the Labrador Current to the north Lands—a series of steep canyons, extending from the top of the and west, and the Acadian and Virginian Atlantic Regions (the shelf break through the slope to the abyssal plain. Though the neritic regions) to the west—is an important and highly produc- region is not within the Gulf Stream current (the Gulf Stream is tive region for over 250 fish species, including bluefin tuna and south and east of the region), it is strongly influenced by it, and Atlantic white marlin. Extending from waters off Cape Hatteras is prone to anti-cyclonic warm core eddy incursions, which spin to north of the Grand Banks, the region does not border any con- off of the Stream and meander westward to the shelf break. These tinental landmass, but overlies several important bathymetric warm core rings can be as large as the state of and features of the northwestern Atlantic, such as the Canyon Lands, carry parcels of warm water far northward of their general prov- Pickett Seamount and the New England Seamount chain. This enance. Sea surface temperatures of the region can range in Janu- once remote marine region is becoming increasing under pres- ary from 10°C at the cold western edge to 18°C at the eastern sure from fishing due to new deep-sea and open ocean technolo- boundary with the Gulf Stream. In summer, surface temperatures gies and equipment. range between 12º and 25°C. Sediment types of the region are mostly silts and clays delivered from the continental land mass. Physical and Oceanographic Setting The Northern Gulf Stream Transition Region, lying east of Biological Setting regions 7 and 8, begins at the shelf break and extends seaward Over 250 fish species have been recorded in this important and over North Atlantic deep waters. The region is composed of Gulf highly productive area. The deep waters of this region are home to high densities of bluefin tuna and blue and white marlins. 10 The actual Gulf Stream and its associated rings extend to the east, beyond the EEZ. Pelagic features such as these meander and move, and are not fixed in time and space. Great northern congregate on the continental slope to

53 Human Activities and Impacts Fact Sheet The Northern Gulf Steam Transition Region encompasses a vast Rationale: characterized by currents and sea surface temperatures from the adjacent Gulf Stream, distance, much of which is threatened by . Where much including moderated water temperatures and the frequent presence of warm core and cold core of this region was not greatly exploited by fishing in the past, new rings; a pelagic area offshore from the NW Atlantic, extending from the shelf break to the EEZ and northward from Cape Hatteras to where the Gulf Stream diverges to the northeast technologies, such as remotely operated vehicles, video, sea sur- Surface: 796,365 km2 face temperature images, bottom landers, submarines and sonar, as Sea surface temperature: 10–18°C (winter), 12–25°C (summer) well as sturdier winches, stronger cable, and more powerful engines Major currents and gyres: warm core rings formed from the adjacent Gulf Stream have allowed fishing trawlers to extend their reach to depths of Physiography: one of the few non-coastal regions, this ecoregion extends from shelf break 900 m and beyond. Moreover, because: a) fishing effort is more to the deep ocean difficult to control on the high seas and b) deepwater species are Depth—shelf (roughly 0–200 m): 0%; slope (roughly 200–2,500/3,000 m): 45%; abyssal plain slower growing, longer lived and reproduce later in life, deepwa- (roughly 3,000+ m): 55% ter fisheries are not particularly sustainable. While proposals are Major community types and subtypes: deep ocean benthos, pelagic fisheries, deepwater gorgonian being developed to ensure the protection of habitat and sustain- corals, octocoral gardens ability of pelagic fisheries, it is generally accepted that the open Productivity: moderately high (150–300 g C/m2/yr) water areas are underrepresented and unprotected in much of the Species at risk: sperm, fin, humpback and North Atlantic right whales; loggerhead and leatherback turtles; Atlantic white marlin northwest Atlantic. Bycatch is also an issue for the Northern Gulf Human activities and impacts: Overfishing has affected some species. For instance, the Atlantic Stream Transition Region. As within the Gulf of Mexico, inciden- white marlin, found throughout the western Atlantic usually above the thermocline in deep pelagic tal take and entanglement of sea turtles and other species occurs waters, is a victim of overfishing and current stocks are 5–15 percent of carrying capacity. Bluefin in this area. Moreover, US Navy sonar exercises also likely affect and bigeye tuna have also been heavily overfished in the region. many marine species (NRC 2003).

This area is also affected by pollution—particularly plastics and depths of 500 m, and Northern Atlantic right, fin, humpback and hydrocarbons that accumulate in driftlines and at convergence sperm whales migrate throughout the region. Several species of zones. Fish and eggs and juveniles, as well as juvenile sea turtle, including the loggerhead, and leatherback, as well as sea turtles and even adult seabirds are affected. common, Risso’s, bottlenose and Atlantic white-sided dolphin are also commonly observed in this region. The region also rep- resents one of the major breeding areas for the gray seal in east- ern North America. Atlantic herring, , mackerel, hake and pollock are abundant. These offshore waters are important areas for several avian species, including northern fulmars, storm- petrels, alcids, shearwaters and gannets.

Because the region is a transition zone between the warm tropi- cal waters to the south and the cold Labrador Current to the north, there is often a large migratory component to the species composition of the fish communities. Many of the residents are eurythermic tropical or warm-temperate forms migrating from the south for periods when the water temperature is high. Thus, while species diversity is high, relatively few species are endemic to the area.

54 Marine Ecoregions of North America The famous blunt-nosed sperm whales favor the deeper and more temperate oceanic waters. Photo: Brandon D. Cole