Relative Catch Performance of Two Gear Modifications Used to Reduce Bycatch of Undersized Fish and Shrimp in Mediterranean Bottom Trawl Fisheries

The catch of large quantities sublegal-sized fish and shrimp is a pervasive feature bottom trawl fisheries, particularly in the Mediterranean demersal mixed fisheries where regulations traditionally allow small mesh sizes. To address these concerns, two net selectivity trials were carried out 2019 2020 on fishing grounds worked by fleet Spanish Mediterranean, under normal commercial operating conditions with volunteer trawlers local fleet. traditional otter employed fishery was modified 50-mm T90 panel extension piece different configurations (front back piece). A second modification consisted inserting selective grid standard net. species investigated European Hake Merluccius merluccius, Red Mullet Mullus barbatus, Striped surmuletus, deepwater rose Parapenaeus longirostris. Important improvements observed for shrimp, trial, 95% 100%, respectively, undersize specimens escaped through grid. design allowed reduction 35% individuals Hake, but no difference gained sizes both spp. retained cod end. adoption gear modifications might contribute to reducing discards fractions target species.