Have you ever wondered why rockfishes get pressure-trauma injuries? Have you ever seen a "popped" rockfish floating like a balloon on the ocean surface?
A new video, produced in part with funding from California Sea Grant, aims to reduce rockfish deaths from barotrauma (literally "pressure wound") by showing anglers how to get fish back down.
The 9-minute video is entertaining with catchy rap music and a wise-cracking rockfish hand puppet, but the message is serious.
Several species of rockfish have been overfished and are now protected. Large tracks of the seafloor off the U.S. West Coast have been closed to bottom fishing to rebuild the most vulnerable of these species. Recreational fishers have limits on rockfish catches and must release rockfishes when their quotas are met, or if they have accidentally caught a protected species.
In the video, anglers are shown very simple and practical ways to redescend rockfishes to improve the fishes' chances of survival. The techniques, which include using a weighted inverted milk crate, barbless weighted hooks and weighted grippers, were discussed at the 2012 Pacific FishSmart Barotrauma Workshop.
Deep-water rockfishes are especially vulnerable to barotrauma because they experience a greater change in pressure (depth) when reeled in. A rockfish with barotrauma may have "popped" eyes and its stomach may be sticking out of its mouth, the result of its swim bladder expanding. A fish released with these conditions likely cannot swim down on its own and left floating at the surface will be at high risk of predation.
Alena Pribyl and John Hyde, both at NOAA Southwest Fisheries Science Center, are the lead scientists on the project "Is Barotrauma Keeping You Up? Try Getting Down with Recompression!" - funded through the Ocean Protection Council's Collaborative Fisheries Research West small grants program, in partnership with California Sea Grant.
The educational outreach project builds on a body of science, some of it funded by Sea Grant, that has rigorously documented the ability to increase West Coast rockfish survival rates by returning the fish to depth.
Written by Christina Johnson