21st Regular Session of the Scientific Committee

SC21 will revisit regional-scale bycatch estimates for the WCPFC longline fishery, following the previous review conducted at SC19. The earlier work, which covered the 2003–2021 period, provided modeled estimates for a wide range of bycatch groups, including finfish, billfish, sharks and rays, marine mammals, and sea turtles, based on available observer data. That analysis highlighted key limitations, including low and spatially imbalanced observer coverage (especially in the northwest Pacific), challenges in estimating gear configuration (such as hooks between floats), and difficulties modeling catch rates for rarely observed species. Nevertheless, the trends in catch rates were considered more informative than absolute catch numbers.

SC21 will review updated estimates and assess methodological improvements made since the previous iteration. These may include enhanced modeling techniques, improved integration of uncertainty (e.g., in gear deployment data), and expanded coverage of observer data, possibly including electronic monitoring. SC21 will provide recommendations on further work as needed.