Influence of temporal regulations on harvest and discards in the recreational Gulf of Mexico gag (Mycteroperca microlepis) fishery

Abstract

Changes in fishery regulations intended to constrain harvest can have profound effects on angler behavior – such as the decision to fish or the choice to retain or discard fish – and influence exploited fish stocks in complex ways. Without understanding these interactions, well-intended regulations may have unintended consequences. This study used statistical models to analyze the impact of temporal closures on recreational harvest and discards in the Gulf of Mexico reef fishery, and focused specifically on gag (Mycteroperca microlepis) along Florida’s west coast. We developed two models within an integrated framework: one for gag harvest and another for gag discards. Both harvest and discards were influenced by regional abundance, effort, seasonality, and temporal restrictions. Using these models in conjunction with estimates of fishing effort and gag discard mortality, we simulated harvest, discards, and dead discards under three counterfactual scenarios considered by fisheries managers with differing recreational season start dates (June, September, and November) to assess the changes in discard and dead discard projections relative to a baseline in which the gag season was closed all year. Simulations suggested that a recreational gag season starting in June, September, or November would exceed an annual catch target of 635,000 lbs gutted weight in 27, 59, and 27 days on average, respectively. A recreational season starting in June yielded the highest number of dead discards relative to the baseline, while seasons starting in September or November resulted in statistically fewer dead discards. We conclude that the Gulf of Mexico gag recreational season start date influences overall gag dead discards, and that a recent decision to shift the recreational gag season from June to September both increased the season duration while also likely lowering fishing pressure on the Gulf of Mexico gag stock.