Effectiveness of Venting and Descender Devices at Increasing Rates of Postrelease Survival of Black Sea Bass

Abstract

AbstractWe tested the ability of venting and descender (recompression) devices to increase the relative survival of released Black Sea Bass Centropristis striata, a physoclistous reef species with high discard rates in hook‐and‐line fisheries that operate in the U.S. Atlantic Ocean and Gulf of Mexico. We caught fish via hook and line from waters that were 38 m deep, a depth where Black Sea Bass often exhibit signs of barotrauma and may be unable to submerge after release. Fish were conventionally tagged and vented with either an 11‐gauge cannula or a 16‐gauge needle, descended using a descender (recompression) device, or released as tagged controls (no venting or recompression). Tests of independence were used to determine the relationship between submergence and treatment (excluding recompressed fish) as well as between submergence and tag return rate. Tag‐recapture data were used to inform a Cox proportional hazards model that evaluated the survival of fish treated with each experimental device relative to the control group. A significantly greater proportion of fish submerged when treated with either venting device relative to the controls, and the fish that submerged had a greater proportion of tag returns relative to those that did not submerge. Venting and recompression increased postrelease survival compared with the controls. The results provide guidance to managers who seek methods to reduce discard mortality rates in hook‐and‐line fisheries for this important species. Future studies should examine the use of these devices at a range of depths to determine their effectiveness.