Performance of a bycatch reduction device in the shrimp fishery of the Gulf of California, Mexico

Although shrimp fisheries are of great economic importance worldwide, they produce serious ecological disturbances and affect other resource harvestin g activities such as small-scale fisheries. We tested performance of the Sq uare Mesh/Extended Funnel bycatch reduction device (BRD) in the bottom traw l shrimp fishery of the Gulf of California. Efficiency of the BRD was deter mined under controlled conditions in terms of exclusion rate of fish bycatc h, shrimp-capture loss and exclusion of certain fish species selected as in dicators. Average exclusion rate for finfish species was 37% and that for s hrimp, 7%. Total bycatch was decreased by 40% in comparison to the control trawl (no BRD). Extrapolation of this result to the entire commercial fleet suggests that BRD use would allow the exclusion of 73 thousand tons of byc atch per year in the Gulf. Their use would also help the recovery of certai n endangered species, such as Totoaba macdonaldi. For this endemic fish, th e exclusion rate of juveniles in our trials was 81%. An economic analysis s howed that with a shrimp-capture loss of 7%, an average shrimp boat will co ntinue to realize profits, but that opportunity costs could make this type of shrimping financially unattractive. (C) 2000 Elsevier Science Ltd. All r ights reserved.