Effect of an Increase in Codend Mesh Size on Discarding in theLoligoSquid-Directed Fishery: A Commercial-Scale Test

Abstract

Discard reduction of juvenile fish and other unwanted bycatch species has been identified as a primary tool in achieving rebuilding and mortality objectives of current fishery management plans. Management of the offshore Loligo pealei squid fishery is particularly challenging because the legal codend mesh size is smaller than other regulated commercial fisheries. Co-occurrence of adult Loligo with juveniles and other Mid-Atlantic species of concern, coupled with the high volume of landings may lead to high discarding of non-target species. Accordingly, an increase in codend mesh size from the 2005 legal size of 1.875 was evaluated as a means to reduce the capture of submarket-size squid, butterfish, and other species of concern, without materially impacting the catch of market-size squid. To evaluate the influence of fishing practice, a commercial-scale test was undertaken. A 2.5 mesh codend, in addition to the desired reduction of small Loligo, resulted in a substantial decrease in the catch of intermediate-size, but marketable (10–13 cm), squid without significant reduction in the bycatch of butterfish, silver hake or spiny dogfish. To recover total catch of market-size squid with the 2.5 mesh codend would require an increase in fishing effort of 73.9%. Even with that increase, total discards of small squid would be reduced by 52.7%. However, total discards of bycatch species would be substantially increased. Codend mesh size is an effective option only if discarding of bycatch species is inconsequential or if avoidance of unwanted catch can be achieved through area management.