Atlantic Sturgeon Marine Bycatch and Mortality on the Continental Shelf of the Northeast United States

Abstract

Protected sturgeon Acipenser spp. are caught in a number of different commercial fishing gears along the east coast of the USA. During their life cycle, Atlantic sturgeon Acipenser oxyrinchus migrate into marine waters, where they are caught by otter trawls, sink gill nets, and drift gill nets targeting other species. We investigated fishing records collected by onboard observers to calculate Atlantic sturgeon bycatch and mortality rates for each fishing gear. Bycatch rates were based on fishing trips monitored between 1989 and 2000 and were indexed by landed species and state. Rates were then raised to fisherywide estimates of bycatch based on total landings for the relevant gears at each location. Where data were available, we estimated sturgeon mortality for each gear. The results showed that Atlantic sturgeon bycatch was highest for sink gill nets in specific areas of the coast. The observed immediate mortality rates of Atlantic sturgeon captured in sink gill nets and drift gill nets were 22% and 10%, respectively, suggesting that annual mortality in these fisheries may be on the order of 1,500 fish per year. The resulting mortality estimates are a source of concern for the continued recovery of Atlantic sturgeon resources.