Critical habitat is designated for the Gulf of Maine, New York Bight, Chesapeake Bay, Carolina, and South Atlantic DPSs of Atlantic sturgeon as described in paragraphs (a) through (h) of this section. The maps, clarified by the textual descriptions in paragraphs (d) through (h) of this section, are the definitive source for determining the critical habitat boundaries.

(a) Critical habitat for the Gulf of Maine, New York Bight, and Chesapeake Bay DPSs of Atlantic sturgeon. The physical features essential for the conservation of Atlantic sturgeon belonging to the Gulf of Maine, New York Bight, and Chesapeake Bay DPSs are those habitat components that support successful reproduction and recruitment. These are:

(1) Hard bottom substrate (e.g., rock, cobble, gravel, limestone, boulder, etc.) in low salinity waters (i.e., 0.0-0.5 parts per thousand range) for settlement of fertilized eggs, refuge, growth, and development of early life stages;

(2) Aquatic habitat with a gradual downstream salinity gradient of 0.5 up to as high as 30 parts per thousand and soft substrate (e.g., sand, mud) between the river mouth and spawning sites for juvenile foraging and physiological development;

(3) Water of appropriate depth and absent physical barriers to passage (e.g., locks, dams, thermal plumes, turbidity, sound, reservoirs, gear, etc.) between the river mouth and spawning sites necessary to support:

(i) Unimpeded movement of adults to and from spawning sites;

(ii) Seasonal and physiologically dependent movement of juvenile Atlantic sturgeon to appropriate salinity zones within the river estuary; and

(iii) Staging, resting, or holding of subadults or spawning condition adults. Water depths in main river channels must also be deep enough (e.g., at least 1.2 meters) to ensure continuous flow in the main channel at all times when any sturgeon life stage would be in the river;

(4) Water, between the river mouth and spawning sites, especially in the bottom meter of the water column, with the temperature, salinity, and oxygen values that, combined, support:

(i) Spawning;

(ii) Annual and interannual adult, subadult, larval, and juvenile survival; and

(iii) Larval, juvenile, and subadult growth, development, and recruitment (e.g., 13 to 26 °C for spawning habitat and no more than 30 °C for juvenile rearing habitat, and 6 milligrams per liter (mg/L) or greater dissolved oxygen for juvenile rearing habitat).

(5) Pursuant to ESA section 4(a)(3)(B)(i), critical habitat for the New York Bight and Chesapeake Bay DPSs of Atlantic sturgeon does not include the following areas owned or controlled by the Department of Defense, or designated for its use, that are subject to an integrated natural resource management plan prepared under section 101 of the Sikes Act (16 U.S.C. 670a), and for which we have determined that such plan provides a conservation benefit to the species, and its habitat, for which critical habitat is designated.

(i) The Department of the Army, U.S. Military Academy—West Point, NY;

(ii) The Department of the Air Force, Joint Base Langley—Eustis, VA;

(iii) The Department of the Navy, Marine Corps Base Quantico, VA;

(iv) The Department of the Navy, Naval Weapons Station Yorktown, VA; and,

(v) The Department of the Navy, Naval Support Facility Dahlgren, VA.

(6) Pursuant to ESA section 3(5)(A)(i), critical habitat for the Gulf of Maine, New York Bight, and Chesapeake Bay DPSs of Atlantic sturgeon does not include existing (already constructed), as of September 18, 2017, manmade structures that do not provide the physical features such as aids-to-navigation (ATONs), artificial reefs, boat ramps, docks, or pilings within the legal boundaries of designated critical habitat.

(b) Critical habitat for the Carolina and South Atlantic DPSs of Atlantic sturgeon. The physical features essential for the conservation of Atlantic sturgeon belonging to the Carolina and South Atlantic DPSs are those habitat components that support successful reproduction and recruitment. These are:

(1) Hard bottom substrate (e.g., rock, cobble, gravel, limestone, boulder, etc.) in low salinity waters (i.e., 0.0-0.5 parts per thousand range) for settlement of fertilized eggs and refuge, growth, and development of early life stages;

(2) Aquatic habitat inclusive of waters with a gradual downstream gradient of 0.5 up to as high as 30 parts per thousand and soft substrate (e.g., sand, mud) between the river mouth and spawning sites for juvenile foraging and physiological development;

(3) Water of appropriate depth and absent physical barriers to passage (e.g., locks, dams, thermal plumes, turbidity, sound, reservoirs, gear, etc.) between the river mouth and spawning sites necessary to support:

(i) Unimpeded movement of adults to and from spawning sites;

(ii) Seasonal and physiologically dependent movement of juvenile Atlantic sturgeon to appropriate salinity zones within the river estuary; and

(iii) Staging, resting, or holding of subadults or spawning condition adults. Water depths in main river channels must also be deep enough (at least 1.2 meters) to ensure continuous flow in the main channel at all times when any sturgeon life stage would be in the river;

(4) Water quality conditions, especially in the bottom meter of the water column, with temperature and oxygen values that support:

(i) Spawning;

(ii) Annual and inter-annual adult, subadult, larval, and juvenile survival; and

(iii) Larval, juvenile, and subadult growth, development, and recruitment. Appropriate temperature and oxygen values will vary interdependently, and depending on salinity in a particular habitat. For example, 6.0 mg/L dissolved oxygen or greater likely supports juvenile rearing habitat, whereas dissolved oxygen less than 5.0 mg/L for longer than 30 days is less likely to support rearing when water temperature is greater than 25 °C. In temperatures greater than 26 °C, dissolved oxygen greater than 4.3 mg/L is needed to protect survival and growth. Temperatures of 13 to 26 °C likely support spawning habitat.

(5) Pursuant to ESA section 4(a)(3)(B)(i), critical habitat for the Carolina DPS of Atlantic sturgeon does not include certain waters of the Cooper River, South Carolina, adjacent to Joint Base Charleston. These areas are described in 33 CFR 334.460(a)(8)(ii)-(iv), 33 CFR 334.460(a)(9), and 33 CFR 334.460(a)(10).

(6) Pursuant to ESA section 3(5)(A)(i), critical habitat for the Carolina and the South Atlantic DPSs of Atlantic sturgeon does not include existing (already constructed), as of September 18, 2017, manmade structures that do not provide the physical features such as aids-to-navigation (ATONs), artificial reefs, boat ramps, docks, or pilings within the legal boundaries of designated critical habitat.

(c) States and counties affected by this critical habitat designation. Critical habitat is designated for the following DPSs in the following states and counties:

(d) Critical habitat boundaries for the Gulf of Maine DPS. Critical habitat for the Gulf of Maine DPS of Atlantic sturgeon is the waters of:

(1) Penobscot River main stem from the Milford Dam downstream to where the main stem river drainage discharges at its mouth into Penobscot Bay;

(2) Kennebec River main stem from the Ticonic Falls/Lockwood Dam downstream to where the main stem river discharges at its mouth into the Atlantic Ocean;

(3) Androscoggin River main stem from the Brunswick Dam downstream to where the main stem river drainage discharges into Merrymeeting Bay;

(4) Piscataqua River from its confluence with the Salmon Falls and Cocheco rivers downstream to where the main stem river discharges at its mouth into the Atlantic Ocean as well as the waters of the Cocheco River from its confluence with the Piscataqua River and upstream to the Cocheco Falls Dam, and waters of the Salmon Falls River from its confluence with the Piscataqua River and upstream to the Route 4 Dam; and

(5) Merrimack River from the Essex Dam (also known as the Lawrence Dam) downstream to where the main stem river discharges at its mouth into the Atlantic Ocean.

(6) Maps of the Gulf of Maine DPS follow:

(e) Critical habitat boundaries of the New York Bight DPS. Critical habitat for the New York Bight DPS of Atlantic sturgeon is the waters of:

(1) Connecticut River from the Holyoke Dam downstream to where the main stem river discharges at its mouth into Long Island Sound;

(2) Housatonic River from the Derby Dam downstream to where the main stem discharges at its mouth into Long Island Sound;

(3) Hudson River from the Troy Lock and Dam (also known as the Federal Dam) downstream to where the main stem river discharges at its mouth into New York City Harbor; and

(4) Delaware River at the crossing of the Trenton-Morrisville Route 1 Toll Bridge, downstream to where the main stem river discharges at its mouth into Delaware Bay.

(5) Maps of the New York Bight DPS follow:

(f) Critical habitat boundaries of the Chesapeake Bay DPS. Critical habitat for the Chesapeake Bay DPS of Atlantic sturgeon is the waters of:

(1) Potomac River from the Little Falls Dam downstream to where the main stem river discharges at its mouth into the Chesapeake Bay;

(2) Rappahannock River from the U.S. Highway 1 Bridge, downstream to where the river discharges at its mouth into the Chesapeake Bay;

(3) York River from its confluence with the Mattaponi and Pamunkey rivers downstream to where the main stem river discharges at its mouth into the Chesapeake Bay as well as the waters of the Mattaponi River from its confluence with the York River and upstream to the Virginia State Route 360 Bridge of the Mattaponi River, and waters of the Pamunkey River from its confluence with the York River and upstream to the Nelson's Bridge Road Route 615 crossing of the Pamunkey River;

(4) James River from Boshers Dam downstream to where the main stem river discharges at its mouth into the Chesapeake Bay at Hampton Roads; and

(5) Nanticoke River from the Maryland State Route 313 Bridge crossing near Sharptown, MD to where the main stem discharges at its mouth into the Chesapeake Bay as well as Marshyhope Creek from its confluence with the Nanticoke River and upriver to the Maryland State Route 318 Bridge crossing near Federalsburg, MD.

(6) Maps of the Chesapeake Bay DPS follow:

(g) Critical habitat boundaries of the Carolina DPS. The lateral extent for all critical habitat units for the Carolina DPS of Atlantic sturgeon is the ordinary high water mark on each bank of the river and shorelines. Critical habitat for the Carolina DPS of Atlantic sturgeon is:

(1) Carolina Unit 1 includes the Roanoke River main stem from the Roanoke Rapids Dam downstream to rkm 0;

(2) Carolina Unit 2 includes the Tar-Pamlico River main stem from the Rocky Mount Millpond Dam downstream to rkm 0;

(3) Carolina Unit 3 includes the Neuse River main stem from the Milburnie Dam downstream to rkm 0;

(4) Carolina Unit 4 includes the Cape Fear River main stem from Lock and Dam #2 downstream to rkm 0 and the Northeast Cape Fear River from the upstream side of Rones Chapel Road Bridge downstream to the confluence with the Cape Fear River;

(5) Carolina Unit 5 includes the Pee Dee River main stem from Blewett Falls Dam downstream to rkm 0, the Waccamaw River from Bull Creek downstream to rkm 0, and Bull Creek from the Pee Dee River to the confluence with the Waccamaw River;

(6) Carolina Unit 6 includes the Black River main stem from Interstate Highway 95 downstream to rkm 0 (the confluence with the Pee Dee River); and

(7) Carolina Unit 7 includes the Santee River main stem from the Wilson Dam downstream to the fork of the North Santee River and South Santee River distributaries, the Rediversion Canal from the St. Stephen Powerhouse downstream to the confluence with the Santee River, the North Santee River from the fork of the Santee River and South Santee River downstream to rkm 0, the South Santee River from the fork of the Santee River and North Santee River downstream to rkm 0, the Tailrace Canal from Pinopolis Dam downstream to the West Branch Cooper River, the West Branch Cooper River from the Tailrace Canal downstream to the confluence with the East Branch Cooper River, and the Cooper River from confluence of the West Branch Cooper River and East Branch Cooper River tributaries downstream to rkm 0, not including the area described in paragraph (b)(5) of this section.

(8) Maps of the Carolina DPS follow:

(h) Critical habitat boundaries of the South Atlantic DPS. The lateral extent for all critical habitat units for the South Atlantic DPS of Atlantic sturgeon is the ordinary high water mark on each bank of the river and shorelines. Critical habitat for the South Atlantic DPS of Atlantic sturgeon is:

(1) South Atlantic Unit 1 includes the North Fork Edisto River from Cones Pond downstream to the confluence with the South Fork Edisto River, the South Fork Edisto River from Highway 121 downstream to the confluence with the North Fork Edisto River, the Edisto River main stem from the confluence of the North Fork Edisto River and South Fork Edisto River tributaries downstream to the fork at the North Edisto River and South Edisto River distributaries, the North Edisto River from the Edisto River downstream to rkm 0, and the South Edisto River from the Edisto River downstream to rkm 0;

(2) South Atlantic Unit 2 includes the main stem Combahee-Salkehatchie River from the confluence of Buck and Rosemary Creeks with the Salkehatchie River downstream to the Combahee River, the Combahee River from the Salkehatchie River downstream to rkm 0;

(3) South Atlantic Unit 3 includes the main stem Savannah River (including the Back River, Middle River, Front River, Little Back River, South River, Steamboat River, and McCoy's Cut) from the New Savannah Bluff Lock and Dam downstream to rkm 0;

(4) South Atlantic Unit 4 includes the main stem Ogeechee River from the Mayfield Mill Dam downstream to rkm 0;

(5) South Atlantic Unit 5 includes the main stem Oconee River from Sinclair Dam downstream to the confluence with the Ocmulgee River, the main stem Ocmulgee River from Juliette Dam downstream to the confluence with the Oconee River, and the main stem Altamaha River from the confluence of the Oconee River and Ocmulgee River downstream to rkm 0;

(6) South Atlantic Unit 6 includes the main stem Satilla River from the confluence of Satilla and Wiggins Creeks downstream to rkm 0; and

(7) South Atlantic Unit 7 includes the main stem St. Marys River from the confluence of Middle Prong St. Marys and the St. Marys Rivers downstream to rkm 0.

(8) Maps of the South Atlantic DPS follow:

[82 FR 39239, Aug. 17, 2017]