Distribution, Habitat Use, and Size of Atlantic Sturgeon Captured during Cooperative Winter Tagging Cruises, 1988-2006
R. Wilson Laney, Joseph E. Hightower, Beth R. Versak, Michael F. Mangold, W. W. Cole, Jr., and Sara E. Winslow
Abstract.—Declines in Atlantic sturgeon Acipenser oxyrinchus abundance in the early 1990s led the Atlantic States Marine Fisheries Commission (ASMFC) to prepare a mandatory fishery management plan. The principal management measures are fishery closure, bycatch assessment, and bycatch reduction in other ASMFC-managed fisheries (i.e., American shad Alosa sapidissima). To better understand Atlantic sturgeon geographic distribution and habitat use, as well as risk of bycatch, we examined offshore distribution of Atlantic sturgeon based on incidental captures in winter tagging cruises conducted off the coasts of Virginia and North Carolina, including in and near extensive sand shoals adjacent to Oregon Inlet and Cape Hatteras. From 1988 to 2006, 146 juvenile Atlantic sturgeon were captured by bottom trawling in depths from 9.1 to 21.3 m. Numbers of Atlantic sturgeon captured and tagged in a given year ranged from 0 (1993, 1995) to 29 (2006). Atlantic sturgeon were encountered in 4.2% of tows, with the percentage varying from 0 in 1993 and 1995 to 12.6% in 1988. Capture patterns suggested that Atlantic sturgeon were likely aggregating to some degree. Total lengths of captured Atlantic sturgeon ranged from 577 to 1,517 mm (mean of 967 mm), suggesting that most fish were juveniles. Limited tag returns and genetic data suggest that fish wintering off North Carolina constitute a mixed stock. Information about their distribution and habitat utilization should benefit fishery managers seeking to reduce bycatch and protect key habitats.