Development and Testing Release Panel Sharks and Non-target Finfish in Purse Seine gear

Dive surveys were conducted inside the purse seine net during a research cruise conducted in the WCPO in support of the International Seafood Sustainability Foundation (ISSF) BycatchProject aimed at reducing no-target fishing mortality in the fishery. Segregation of tuna by size and species and between tuna and non-target species was repeatedly observed supporting the potential for selective release of non-target species from the net. In particular, silky sharks (Carcharhinus falciformis) were observed to collect in a pocket of net that often formed toward the latter stages of net retrieval. An experimental release panel was installed at this location measuring 5.5 wide that extended down from the corkline for approximately 11 m. The panel could be opened and closed with minimal loss in time to the fishing operation and with low risk of losing target catch. The release panel was tested during seven sets but only two silky sharks exited the panel. Although the panel failed to release significant quantities of non-target catch in these experimental trials, we feel that further refinement of this concept with additional testing and experimentation is warranted.