Technical conservation measures in New England small-mesh trawl fisheries: Current status and future prospects

Small-mesh otter trawls, which use 76 mm or less codend mesh sizes, are considered "exempt" gears in some fishery management plans in the US. In New England, small-mesh trawls are utilized to capture small-bodied Northern shrimp (Pandalus borealis), silver hake (Merluccius bilinearis), and longfin inshore squid (Doryteuthis pealeii), which are too small to be retained by traditional “large-mesh” groundfish trawls with 165 mm mesh size codends. Due to small-mesh codends, these fisheries have historically discarded large amounts of important, juvenile groundfish species along with other bycatch species. Bycatch reduction strategies in these fisheries have focused on the design and implementation of bycatch reduction devices (BRDs) that separate target and bycatch species within the trawl. Species separation in small-mesh trawls often rely on behavioral differences between target and bycatch species, which are typically determined using under water video recordings. Behavioral differences, which occur at the BRD, allow the capture of targeted species and the escape of bycatch species. This paper reviewed BRD research and implementation in these fisheries, and discussed existing issues and future directions for research and development. This review suggests that: (1) the Northern shrimp fishery can improve bycatch reduction by combining additional BRDs with the Nordmøre grid, and preferably the BRDs should be placed in the front part of the trawl to reduce bycatch stress and injury; (2) the silver hake fishery should be allowed more BRD options throughout its fishery; (3) and the longfin inshore squid fishery should apply drop-chain-style trawls to reduce the capture of demersal species, but more research remains to reduce the capture of schooling, pelagic fish.