Primary factors affecting sturgeon populations in the southeastern United States: Fishing mortality and degradation of essential habitats

Atlantic and shortnose sturgeons are highly valued for their eggs (caviar) and flesh, but stocks of both species are depleted. The shortnose sturgeon is listed as an endangered species, and a long-term (multidecade) moratoriu m on fishing for Atlantic sturgeon is specified in the recently updated fis hery management plan of the Atlantic States Marine Fisheries Commission. Th us, identification, protection, and enhancement of essential habitats are p riority issues for management agencies. As anadromous (Atlantic) and nearly anadromous (shortnose) species, these sturgeons use a wide variety of habi tats; variations occur latitudinally, seasonally, and among different life stages. Spawning habitats have been identified in two southeastern rivers f or shortnose sturgeon, but to date no spawning sites have been verified for Atlantic sturgeon. Some life stages of both species (including young juven iles) concentrate in or are restricted to small portions of estuaries durin g summer. Deterioration of water quality (especially dissolved oxygen) appe ars to be degrading the nursery function of these summer refugia, creating a recruitment bottleneck, Protection of essential habitats, especially nurs ery/summer habitats, from human-caused dissolved-oxygen reductions and othe r impacts is critical. By-catch, primarily in riverine/estuarine gillnet an ti estuarine/marine trawl fisheries, appears to be the second major source of mortality for southern sturgeons. Reserves, or no-fishing zones, could p rotect populations by reducing or eliminating by-catch mortality. This prot ection would be especially valuable in high salinity foraging areas (used p rimarily during cool months) and during spawning migrations. Proposed manag ement strategies aimed at conservation and restoration of sturgeon Copulati ons therefore focus on two areas: protection of essential habitats and esta blishment of reserves to provide protection from fishing gears that generat e substantial sturgeon by-catch. Specific management recommendations were d eveloped on a system-by-system basis.