Delayed Recovery and Behavioral Competency of Recompressed Yelloweye Rockfish,Sebastes ruberrimus

Rebuilding of some U.S. west coast rockfish stocks relies heavily on mandatory fishery discard, however the long-term condition of these fish, which experience capture-related barotrauma, is unknown. We conducted two studies designed to evaluate delayed mortality, physical condition, and behavioral competency of recompressed yelloweye rockfish following capture-related barotrauma.  First, we used sea-cage and laboratory holding to evaluate fish condition at 15 and 30-days post-capture from 140-150 m depth.  All external barotrauma signs resolved upon recompression, but fish that survived (10/12) had compromised buoyancy, swim bladder injuries, blood clots and/or active hemorrhaging in the body cavity.  For the second study, we used a video-equipped sea-cage to observe fish orientation, swimming competency, and visual capability for one hour following recompression and return to the sea floor.  Trials were conducted with 24 fish captured from 54-199 m water depth. All fish survived, but 50% of fish from the deepest depth ranges showed impairment in their ability to vertically orient. Most deep fish did not exhibit “exploration” behavior and appeared unable to visually discern the difference between an opaque and transparent barrier. These studies suggest physical injuries and behavioral impairment may compromise yelloweye rockfish in the hours and weeks following recompression and release.