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

摘要

Although shrimp fisheries are of great economic importance worldwide, they produce serious ecological disturbances and affect other resource harvesting activities such as small-scale fisheries. This paper tested performance of the Square Mesh/Extended Funnel bycatch reduction device (BRD) in the bottom trawl shrimp fishery of the Gulf of California. Efficiency of the BRD was determined under controlled conditions in terms of exclusion rate of fish bycatch, shrimp-capture loss and exclusion of certain fish species selected as indicators. Average exclusion rate for finfish species was 37% and that for shrimp, 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 73 000 tons of bycatch per year in the Gulf. Their use would also help the recovery of certain endangered species, such as Totoaba macdonaldi. For this endemic fish, the exclusion rate of juveniles inthe trials was 81%. An economic analysis showed that with a shrimp-capture loss of 7%, an average shrimp boat will continue to realize profits, but that opportunity costs could make this type of shrimping financially unattractive.