Rebuilding of some U.S. West Coast rockfish (Sebastes spp.) stocks relies heavily on mandatory fisherydiscard, however the long-term condition of discarded fish experiencing capture-related barotraumais unknown. We conducted two studies designed to evaluate delayed mortality, physical condition,and behavioral competency of yelloweye rockfish, Sebastes ruberrimus, experiencing barotrauma dur-ing capture followed by recompression (assisted return to depth of capture). First, we used sea-cageand laboratory holding to evaluate fish condition at 2, 15, and 30 days post-capture from 140 to 150 mdepth. All external barotrauma signs resolved following 2 days of recompression, but fish that survived(10/12) had compromised buoyancy regulation, swim bladder injuries, and coelomic and visceral hem-orrhages at both 15 and 30 days post-capture. For the second study, we used a video-equipped sea-cageto observe fish behavior for one hour following capture and return to the sea floor. Trials were conductedwith 24 fish captured from 54 to 199 m water depth. All fish survived, but 50% of fish from the deepestdepth ranges showed impairment in their ability to vertically orient (P < 0.01). Most (75%) deep-capturedfish did not exhibit “vision-dependent” behavior (P < 0.001) and appeared unable to visually discern thedifference between an opaque barrier and unobstructed or transparent components of the cage. Thesestudies indicate physical injuries and behavioral impairment may compromise yelloweye rockfish in thehours and weeks following discard, even with recompression. Our results reiterate the importance ofavoiding fishing contact with species under stock rebuilding plans, especially in deep water, and thatspatially-managed rockfish conservation areas remain closed to fishing.
Authors: Rankin, Polly S.; Hannah, Robert W.; Blume, Matthew T.O.; Miller-Morgan, Timothy J.; Heidel, Jerry R.