Marine and Coastal Fisheries: Dynamics, Management and Ecosystem Science, 4(1):46-56, 2012. Paper abstract bibtex
We used a caging system designed to minimize the adverse effects of caging fish in marine waters to evaluate discard mortality of 7 rockfish (Sebastes) species with barotrauma. In total, 288 rockfish were captured, scored for barotrauma, evaluated behaviorally at the surface and caged individually on the seafloor for 48 h to determine survival. With the exception of 3 blue rockfish (Sebastes mystinus), condition of surviving fish after cage confinements from 41-71 h was excellent. At capture depths up to 54 m, survival was 100% for yelloweye (S. ruberrimus, n=25) and copper rockfish (S. caurinus, n=10) and 78% for blue rockfish (n=36). At capture depths up to 64 m, survival was 100% for canary (S. pinniger, n=41) and quillback rockfish (S. maliger, n=28) and 90% for black rockfish (S. melanops, n=144). Black rockfish survival was negatively associated with capture depth (m, P<0.01) and with surface-bottom temperature differential (°C, P<0.01). Blue rockfish survival was negatively associated with capture depth (P<0.01). Barotrauma signs and surface behavior scores were not good indicators of survival potential across species, but were useful within species. In black and blue rockfish, severe barotrauma was negatively associated with survival, while higher scores on reflex behaviors at the surface were positively associated with survival (P<0.01). The high survival rates and excellent condition of some species in this study suggest that requiring hook-and-line fishers to use recompression devices to help discarded rockfish return to depth may increase survival for some species.