Modeling effort in a multispecies recreational fishery; Influence of species-specific temporal closures, relative abundance, and seasonality on monthly angler-trips

Abstract

Seasonal harvest restrictions are a common strategy in fisheries management, designed to mitigate fishing pressure on economically and recreationally valuable fish and invertebrate stocks. However, uncertainty regarding recreational fishing effort responses to seasonal closures can lead to unintended consequences for target and non-target species. This is especially true in the Gulf of Mexico reef fishery, where anglers can switch among multiple target species and discard mortality for co-occurring species is high. Therefore, understanding the drivers of recreational fishing effort is needed to support management decisions. This study addresses knowledge gaps by employing a statistical model to analyze the relationships between recreational reef fish effort (measured in angler-trips) and species-specific seasonal management in the Gulf of Mexico along the west coast of Florida. We focused on ecological and management variables surrounding gag (M. microlepis), red grouper (E. morio), and red snapper (L. campechanus), which are among the most recreationally sought-after species targeted along the west coast of Florida. We also considered environmental covariates such as seasonal patterns, inter-annual changes in species abundance, and socioeconomic factors (i.e., numbers of saltwater fishing licenses sold and economic trends). Our analysis indicated considerable variation in effects of seasonal, environmental, and management predictors on recreational effort that were region-specific. Notably, management predictors related to both red snapper and gag, such as the fraction of a month open to harvest (both species) and the length of the red snapper season, directly influenced recreational effort. Given recent substantial reductions in the Gulf of Mexico gag season, we were particularly interested in the effect of gag management on angler-trips, but we did not find strong evidence that effort concentration has taken place for this species at this time. This information provides foundational insights into the seasonal, biological, and anthropogenic drivers of recreational angler reef fish effort along the west coast of Florida. This model, or related frameworks, could be valuable in forecasting future trends in recreational effort along the west coast of Florida specifically and the Gulf of Mexico more generally, and may be instrumental for managers seeking to comprehend the consequences of changes to seasonal reef fishery management.