Bioeconomic Optimization of Hawaiian Bottomfish Restricted Fishing Areas: An Application of Habitat-Based Species Distribution Modeling

The Hawaii Deep Seven Bottomfish complex of six eteline snappers and one endemic grouper is the most economically important insular fish species in Hawaii. Bottomfish Restricted Fishing Areas (BRFAs) have been implemented since 1998 along with size and gear restrictions, bag limits, vessel registration, and catch quotas. The placement of the 12 current BRFAs was based on historically known habitat features associated with the Deep Seven Bottomfishes, e.g., deep, hard-bottomed, high-relief areas. The main objective of this work was to quantify how well current spatial fisheries management actually captures essential fish habitat for this species complex. The output from habitat-based species distribution models was used to optimize the placement of restricted fishing areas using a commonly used optimization software (MARXAN). The optimization of a network of restricted fishing areas was based on modeled combined species presence and a cost function related to economic value of the fishing area. The optimized placement of the network of reserves was then compared to the current placement of the BRFAs to assess the bioeconomic efficacy of the currently implemented BRFAs. This work is intended as a direct application of multispecies distribution models to provide valuable insight to fisheries management.