Reduction of juvenile red snapper bycatch in the U.S. Gulf of Mexico shrimp trawl fishery

摘要

Bycatch reduction devices (BRDs) have been mandated for use in the U. S. Gulf of Mexico shrimp fishery to reduce shrimp trawl mortality of juvenile red snapper Lutjanus campechanus. Conditional survival of juvenile red snapper from shrimp trawl bycatch has been estimated to be on the order of 12%. The BRDs have been estimated to reduce shrimp trawl bycatch mortality by more than the 50% reduction that has been estimated as necessary to rebuild the stock by the target date of 2019. Results from analyses in this study that used observer data collected during 1992-1996 do not support this contention. A low fraction of the annual bycatch occurs during times of the year when BRDs effectively exclude juvenile red snapper at the sizes encountered. Maximum potential exclusion of juvenile red snapper with the use of BRDs is only about 25-27%, not 59% as has been previously estimated. If rebuilding requires a 50% reduction in age-0 and age-1 red snapper bycatch mortality to achieve the stock recovery targets, this study's results clearly demonstrate that the BRD by itself will not produce the mortality reductions necessary to meet this objective.