Injury Frequency for Discarded Summer Flounder in the Recreational Fishery of the Mid-Atlantic Bight: Influence of Landing Size Regulations

摘要

Summer flounder Paralichthys dentatus supports an important recreational fishery along the northeastern coast of the United States. Successful rebuilding of the stock and the need to constrain landings within total-allowable-landing targets has resulted in declining bag limits, increasing size limits, higher discarding, and a reduction in satisfaction derived from recreational fishing trips. A series of fishing trips were observed in which alternative regulatory scenarios were tested to identify approaches to better optimize bag limits and size limits. The alternatives included a slot limit in which some smaller fish were allowed to be landed, a reduced minimum size, and a cumulative size, in which the bag limit and size limit were conflated such that fish take was controlled by the cumulative size of the landed fish. Comparisons were made to fishing trips conducted under 2006 regulations that produced higher injury frequencies than other regulatory scenarios due to discarding of larger fish that tended to be gut-hooked. Two alternatives performed significantly better in terms of reducing the potential for discard mortality among discarded fish, the slot-limit and the cumulative-size scenarios. An intermediate performance of the reduced-minimum-size scenario was due to an increased proportion of dead fish, but this association was unexplained. Fish uninjured save for minor hook damage were common on all vessels and in all fishing approaches. Injury frequency was, in fact, remarkably low, less than half of the assumed discard mortality rate in present-day stock assessments. The study supports the use of size-specific mortality rates for fish discarded recreationally. The study offers no support for the efficacy of the 2006 regulatory system in controlling discard mortality rate. Any of the alternative plans is an improvement, but the slot-limit and cumulative-size scenarios are deserving of the most scrutiny.