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Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Proposed Rules The Atlantic coast region extends from the Gulf of Maine to the U.S. and Canada border past Cape Hatteras to Florida. The region is characterized by its temperate climate and proximity to the Gulf Stream, and is generally considered to be of moderately high productivity, although the portion of the region from Cape Cod to Cape Hatteras is one of the most productive areas in the world due to upwellings along the shelf break created by the western edge of the Gulf Stream. Sea surface temperatures SST exhibit a broad range across this region, with winter temperatures ranging from 220 C in the north and 1522 C in the south, while summer temperatures, consistent in the south at approximately 28 C, range from 1527 C in the northern portion.
The northern portion of this region i.e., north of Cape Hatteras is more complex, with four major sub-areas: The Gulf of Maine, Georges Bank, southern New England, and the Mid-Atlantic Bight. Cold, low-salinity water transports in the Labrador Current from the Arctic Ocean into the Gulf of Maine and exits through the Great South Channel; upwellings occur around Georges Bank. South of Cape Cod, there is strong stratification along the coast where large estuaries occur e.g., Chesapeake Bay, Pamlico Sound.
The Gulf Stream is highly influential on both the northern and southern portions of the region, but in different ways. Meanders of the current directly affect the southern portion of the Gulf Stream, where it is closer to shore, while warm-core rings indirectly affect the northern portion Belkin et al., 2009. In addition, subarctic influences can reach as far south as the MidAtlantic Bight, but the convergence of the Gulf Stream with the coast near Cape Hatteras does not allow for significant northern influence into waters of the South Atlantic Bight.
Gulf of MaineThe Gulf of Maine GOM is an enclosed coastal sea characterized by relatively cold waters and deep basins. Several geographic features bound the GOM including Browns Bank on the east, Maine and Nova Scotia to the north, Maine, New Hampshire, and Massachusetts on the west, and Cape Cod and Georges Bank to the south. Retreating glaciers 18,000
14,000 years ago formed a complex system of deep basins, moraines, and rocky protrusions, leaving behind a variety of sediment types including silt, sand, clay, gravel, and boulders. There exists patchy distribution of sediments on the seafloor throughout the GOM, with occurrence largely related to the bottom topography.

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Oceanic circulation in the GOM
exhibits a general counterclockwise current, influenced primarily by cold water masses moving in from the Scotian Shelf and offshore. Although large-scale water patterns are generally counterclockwise around the GOM, many small gyres and minor currents do occur. Freshwater runoff from the many rivers along the coast into the GOM
influences coastal circulation as well.
These water movements feed into and affect the circulation patterns on Georges Bank and in Southern New England.
Georges BankGeorges Bank GB is an elongated extension of the northeastern U.S. continental shelf, characterized by a steep slope on its northern edge and a broad, flat, and gently sloping southern flank. The Gulf of Maine lies to the north of GB, the Northeast Channel between GB and Browns Bank is to the east; the continental slope lies to the south, and the Great South Channel separates GB
and Southern New England to the west.
Although the top of GB is predominantly characterized by sandy sediment, glacial retreat during the late Pleistocene era resulted in deposits of gravel along the northern edge of GB, and some patches of silt and clay can be found on the sea floor. The most dominant oceanographic features of GB
include a weak but persistent clockwise gyre that circulates over the whole bank, strong tidal flows mainly northwest and southeast and strong but intermittent storm-induced currents.
The strong tidal currents result in vertically well-mixed waters over the bank. The southwestern flow of shelf and slope water that forms a countervailing current to the Gulf Stream drives the clockwise GB gyre.
Mid-Atlantic BightThe Mid-Atlantic Bight MAB includes the continental shelf and slope waters from GB to Cape Hatteras, NC. The retreat of the last ice sheet shaped the morphology and sediments of the MAB. The continental shelf south of New England is broad and flat, dominated by fine grained sediments sand and silt. Patches of gravel exist in places on the sea floor, such as on the western flank of the Great South Channel.
The shelf slopes gently away from the shore out to approximately 100 to 200
kilometers km 62 to 124 miles mi offshore, where it transforms into the continental slope at the shelf break at water depths of 100 to 200 m 328 to 656 ft. Along the shelf break, numerous deep-water canyons incise the slope and shelf. The sediments and topography of the canyons are much more heterogeneous than the predominantly
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sandy top of the shelf, with steep walls and outcroppings of bedrock and deposits of clay.
The southwestern flow of cold shelf water feeding out of the GOM and off GB dominates the circulatory patterns in this area. The countervailing Gulf Stream provides a source of warmer water along the coast as warm-core rings and meanders break off from the Gulf Stream and move shoreward, mixing with the colder shelf and slope water.
As the shelf plain narrows to the south the extent of the continental shelf is narrowest at Cape Hatteras, the warmer Gulf Stream waters run closer to shore.
Southern New EnglandThe Southern New England SNE subarea extends from the Great South Channel in the east to the MAB in the west. The southwestern flow of cold shelf water feeding out of the GOM and off GB
dominates the circulatory patterns in this area. The SNE continental shelf is a gently sloping region with smooth topography. The shelf is approximately 100 km 62 mi wide, and the shelf break occurs at depths of between 100
to 200 m 328 to 656 ft. The continental slope extends from the shelf break to a depth of 2 km 6,562 ft. This zone has a relatively steep gradient, and the relief is moderately smooth. The continental rise 2 to 6 km; 500 to 19,700 ft is similar to the slope in having only gradual changes in bathymetry.
However, the overall gradient of the continental rise is less than that of the continental slope Theroux and Wigley, 1998. Sediments of the SNE subarea consist of fine-grained sand and silt.
Patches of gravel exist in places on the sea floor, such as on the western flank of the Great South Channel. Currents and historic disposal of dredged material may influence water and sediment quality within the SNE.
Southeast U.S. Continental Shelf Large Marine Ecosystem: This area covers the Atlantic Ocean extending approximately 930 miles from Cape Hatteras, NC south to the Straits of Florida Yoder, 1991. The continental shelf in the region reaches up to approximately 120 miles offshore. The Gulf Stream Current influences the region with minor upwelling occurring along the Gulf Stream front. The area is approximately 115,000 square miles, includes several protected areas and coral reefs Aquarone, 2008; numerous estuaries and bays, such as the Albemarle-Pamlico Sound, nearshore and barrier islands; and extensive coastal marshes that provide valuable ecosystem services and habitats for numerous marine and estuarine species.
A sixto 12-mile wide coastal zone is characterized by high levels of primary
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