Optimization of Hook Size to Reduce Discards and Post Release Mortality in the New Jersey Summer Flounder, Paralichthys dentatus, Hook and Line Fishery

The objective of this study was to determine optimal hook sizes to land legal summer flounder, Paralichthys dentatus, while reducing the number of discards and incidence of deep hooking associated with catch and release.  We evaluated size selectivity of eight J-hooks (2/0-9/0) on flounder landings through collaboration with the NJ Resident Commercial Hook and Line Fishermen.  Sampling trips were conducted in 2014 along the coastline of NJ.  The following data were analyzed as a function of hook size: length (TL), recreational legal fish landed, discards, legal to discard ratio, estimated discard mortality, and hook set location.  A total of 7764 flounder and 280 non target species were landed.  As hook size increased, mean TL significantly increased with 7/0-9/0 size hooks outperforming smaller gauges. Increased hook size decreased the total number of flounder landed while significantly increasing the ratio of legally landed fish.   As hook size increased, estimated discard mortality decreased calculated as 10% mortality rate of discarded fish. Our study concludes that larger hooks lands larger fish while reducing discards and potential mortality.  Further, our results suggest that hook guidelines have the potential to increase recruitment and spawning stock biomass (SSB) through reduction in mortality associated with catch and release.