Effects of using bycatch reduction devices on the Colombian Caribbean Sea shrimp fishery

Effects of the fisheye bycatch reduction device (BRD) and turtle excluder device (TED) on shrimp retention and bycatch reduction were assessed, aiming to increase sustainability and attenuate the ecological impact of shrimp trawls in the Colombian Caribbean Sea. A total of 88 hauls were carried out in two different periods. The four shrimp trawl nets of the fishing vessel were each equipped with a different device configuration: BRD, TED, TED/BRD, and control (without devices). The highest reduction in incidental catch rates was recorded for the BRD-equipped net, whereas a lower reduction of fish, a higher reduction of invertebrates and discards, and a lower retention of shrimp were recorded for the TED-equipped net. Using BRD, a significant reduction in catch per unit effort was recorded for six (Lutjanus synagris, Lepophidium spp., Diplectrum spp., Synodus spp., Syacium spp., and Bagre marinus) of twelve fish species or species groups selected because of their commercial value or higher catch rates. The results indicate that widespread use of BRDs in the southern area of the Colombian Caribbean Sea would allow a decrease of 727 t of bycatch and 37 t of shrimp in the catches per year, whereas using both TED and BRD, these reductions would be 1529 t of bycatch and 128 t of shrimp per year. Some changes in the device designs currently used are considered feasible in order to increase shrimp retention and reduce the resistance of crews to adopt these devices, but at the same time attenuating the impact of fishing activities on bycatch species and recovering the abundances of the exploited demersal fish populations. Con el fin de aumentar la sostenibilidad y atenuar el impacto ecologico de la pesca de arrastre camaronero en el Caribe colombiano, se evaluo el efecto del dispositivo reductor de pesca acompanante tipo fisheye (BRD) y del dispositivo excluidor de tortugas (TED) en la retencion de camaron y la reduccion de pesca acompanante. Se realizaron un total de 88 lances en dos periodos diferentes. Las cuatro redes del barco fueron equipadas con diferentes configuraciones de dispositivos: BRD, TED, TED/BRD y control (sin dispositivos). Con el BRD se registro mayor exclusion de pesca incidental, mientras que con el TED se registro menor exclusion de peces, mayor exclusion de invertebrados y descartes en general, y menor retencion del recurso objetivo (camaron). De doce especies seleccionadas por su importancia comercial o su abundancia en las capturas, seis (Lutjanus synagris, Lepophidium spp., Diplectrum spp., Synodus spp., Syacium spp. y Bagre marinus) mostraron una reduccion significativa en captura por unidad de esfuerzo de la red con BRD, respecto a la red control. Los resultados indican que el uso extensivo del BRD en el area sur del Caribe colombiano permitiria anualmente una disminucion de 727 t en pesca acompanante y de 37 t en camaron, mientras que la combinacion TED/BRD disminuiria 1529 t de pesca acompanante y 128 t de camaron. Se encontro viable introducir algunas modificaciones en el diseno de ambos dispositivos, tendientes a aumentar la retencion de camaron, a fin de disminuir la resistencia de los pescadores para adoptarlos, pero cumpliendo con los objetivos de atenuar el impacto sobre la pesca acompanante y recuperar las abundancias de las poblaciones de peces demersales explotadas.