A Science-Industry Based Partnership to Estimate Discard Mortality and Derive Best Catch-and-Release Guidelines for Haddock in the Gulf of Maine Rod-and-Reel Fishery

Discard mortality estimates are necessary for the determination of fishery management measures and accurate quantification of fishery removals. In the Gulf of Maine recreational groundfish fishery, cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are jointly managed using a bio-economic model wherein the stock size and discard mortality of one species ultimately influences the management of the other. While discard mortality of cod has been recently investigated in this fishery, the question remains unexplored in haddock. To address this, scientific and industry partners estimated the discard mortality of haddock captured in the Gulf of Maine recreational groundfish fishery. The team collected biological, environmental, and technical data on over 2,400 haddock caught with representative rod-and-reel setups and used passive acoustic telemetry to monitor mortality in a subsample (n=156) of discarded haddock. Inclusion of the fishing industry was critical for project design, fieldwork planning and execution, including identification of representative locations and fishing conditions, and data collection. Longitudinal survival analyses in combination with bootstrap techniques using fishery-dependent observations will be used to produce a fishery-wide discard mortality estimate. Moreover, catch-and-release guidelines to reduce mortality will be generated based on analysis of sensible capture variables.