WASHINGTON (CN) - Four populations of Atlantic sturgeon have been listed as "endangered" under the Endangered Species Act, and a fifth has been listed as "threatened," by the National Marine Fisheries Service.
The New York Bight and Chesapeake Bay populations will be listed as endangered while the Gulf of Maine population will be listed as threatened.
According the NMFS, the three northeast populations are threatened by "precipitous declines in population sizes and the protracted period in which sturgeon populations have been depressed," resulting in limited spawning.
The decline in numbers is mostly due to dredging of river areas where the sturgeon spawn, and the corresponding decline in substrate and water quality.
"Positive signs" for the Gulf of Main segment, including demolition of the Veazie Dam on the Penobscot River and the Edwards Dam on the Kennebec River, have improved spawning grounds, leading to the segment's listing as threatened rather than endangered, according to the NMFS.
In the southeast, the Carolina and South Atlantic distinct population segments are similarly endangered by precipitous population declines, in their, cases brought about mostly by dams blocking access to their spawning grounds.
The NMFS says that in the southeast, the number of spawning sturgeons has dwindled to less than 6 percent of historic levels with as few as 300 adults managing to reach their spawning grounds in the rivers of North Carolina, South Carolina, and Georgia.
The situation is the same in the northeast where the NMFS estimates that the spawning population of New York Bight sturgeon is one to two orders of magnitude below historical levels with several rivers lacking any spawners.
The NMFS seeks input on the designation of critical habitat for the northeast populations and is continuing to study the features needed for recovery by the southeast populations.
Under section 9 of the Endangered Species Act all take of species listed as "endangered" is forbidden. Under section 7 of the act, federal agencies must consult with the NMFS before allowing any activity that might have an impact on species listed as "threatened."
Both listings become effective on April 6.
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