Discard mortality of black sea bass (Centropristis striata) in a deepwater recreational fishery off New jersey: Role of swim bladder venting in reducing mortality

Abstract

The effects of barotrauma and other capture-related factors on the discard mortality of black sea bass (Centropristis striata) are poorly understood. The objective of this study Was to estimate the discard mortality rate for black sea bass in the Winter deepwater recreational fishery off New Jersey and to evaluate if swim bladder venting can reduce discard mortality. A total of 1823 fish Were sampled at multiple depths (45, 58, and 67 m) from November 2016 through March 2017. To estimate discard mortality at a depth of 45 m, 96 individuals Were tagged With acoustic transmitters and monitored With acoustic receivers. The majority (95%) of fish captured across all depths exhibited effects of barotrauma, Which Were more prevalent at greater depths. Results from longitudinal survival analyses indicate that venting Was the most significant predictor of mortality at a depth of 45 m, With the estimated mean discard mortality rate being lower for vented (20%) than non-vented (49%) fish. Fight time had the largest statistical influence on the mortality of nonvented fish, Whereas longer fight times (>54 s) resulted in higher mortality at a depth of 45 m. Discard mortality may have been higher at greater depths, but venting and other recommended practices can mitigate mortality at all depths sampled.