Postrelease Survival of Sublegal Southern Flounder Captured in a Commercial Gill-Net Fishery

Abstract

Discards from commercial fisheries may be subject to high rates of mortality that vary over time and space, contributing to inaccuracies in stock assessments. We present the results from a field experiment in the New River estuary, North Carolina, designed to estimate the postrelease survival of commercially gill-netted, sublegal southern flounder Paralichthys lethostigma. Large, replicate field enclosures were used to monitor gill-netted southern flounder for a 3-d period after capture. The survival of observed discards showed significant variation among seasons. During fall and spring, overall survival was estimated to fall between 0.74 and 0.87, while during summer survival was estimated to fall between 0.22 and 0.30 and included fish that were dead when gill nets were retrieved. Logistic regression analysis was used to evaluate the relative effects of individual traits on the postrelease survival of southern flounder in the commercial gill-net fishery. Model selection indicated that season and fish condition were the best characteristics with which to predict postrelease survival and that body size may also influence postrelease survival. Low seasonal estimates of the survival of discarded southern flounder suggest that management measures that mitigate poor discard survival will be most effective during the summer. Received November 11, 2010; accepted February 17, 2011