Trap-Line: An Innovative Fishing Gear for Mediterranean Swordfish Fisheries

This study documents the performance of "trap-lines" used in place of traditional hook-based baits in the Mediterranean swordfish (Xiphias gladius) pelagic longline fishery. Trap-lines consist of concentric monofilament rings combined with artificial bait, and operate using entanglement, rather than hooking. Trap-lines were used on 30% of the fishing units, but accounted for about 51% of the marketable catch, with significantly higher catch per unit effort (CPUE) compared with conventional hooks. Landings per unit effort and median fork length were also larger for trap-lines. Additionally, 95% of non-target catch was associated with standard hooks. These early findings highlight the potential of trap lines to increase fishing efficiency, improve size selectivity, and significantly reduce bycatch in the Mediterranean swordfish fishery.