Developing bycatch reduction devices in tropical tuna purse seine fisheries to improve elasmobranch release

Today most on deck bycatch releases in tuna purse seiners are conducted by hand or simple aids (e.g., canvases, cargo nets). New developments in bycatch reduction devices (BRDs) can assist to decrease impacts on vulnerable bycatch species, including sharks and mobulid rays. Collaborative work with fishers is helping advance in the construction of functional BRD prototypes, which improve crew safety and speed up bycatch release times. New options such as shark velcros, mobulid sorting grids, release ramps, and hoppers with ramps can enhance current release standards. Practical aspects such as low cost, durability, easy handling, and storage can favour their adoption. Designs for some BDRs need to be adapted around individual vessels, and sometimes are limited by available deck spaces and configurations. However, for future purse seiners these selective BRDs should be integrated from the start in the boat design to maximize their efficiency and integration. Finally, we encourage tuna RFMOs to support research and adoption of BRDs for endangered, threatened and protected (ETP) species, incorporating them in their conservation measures and best release practice guidelines.