Meeting Abstract
The National Marine Fisheries Service recently released the Atlantic Highly Migratory Species Management-Based Research Needs and Priorities, with key research needs including establishing post-release mortality rates for commercially caught sharks. Such information is listed as High Priority, and very important in creating effective fisheries management plans for sharks targeted or caught as bycatch in commercial gear. Published at-vessel mortality rates indicate that capture-associated mortality is species-specific. Research assessing interspecific mortality rates is critical, but it is also imperative to understand the physiology underlying such mortality events. The physiological upset sharks experience while captured on fishing gear can result in irreversible cellular damage, resulting in immediate or delayed mortality. Longline research on various coastal sharks reveal some stress physiology parameters are correlated with magnitude of the capture stress (e.g., lactate), and that blood potassium levels are significant (p<0.05) predictors of both at-vessel and post-release mortality. Specifically, the role potassium plays in these mortality events needs to be better understood. The further elucidation of mortality indicators, and what is driving such mortality events, can be used on various scales in the future to predict mortality rates, and develop mitigation measures for fisheries management.
