Assessing the Relative Selectivity of Multiple Sampling Gears for Managed Reef Fishes in the Eastern Gulf of Mexico

Fishery-independent data are important for the effective management of reef fishes in the eastern Gulf of Mexico. Proper characterization of selectivity, or the effectiveness of each type of sampling gear in capturing a species or a size-class, is essential to ensure that assessment models treat various sources of data appropriately. In this study, we analyzed fishery-independent data that was collected using stereo-baited remote underwater video (S-BRUV) arrays, chevron traps (TRAP), and two types of hooked gear (repetitive timed-drop [RTD] and vertical longline [VLL]) to assess gear-related differences of species composition and size selectivity of managed reef fishes in the eastern Gulf of Mexico. Significant differences were detected in the assemblage structures of reef fishes in relation to region, gear type, and depth. Overall, eight managed species were identified as contributing to the top 70% of the assemblage structure for each gear type. Stereo-baited remote underwater video had the highest abundances for most of the species and the highest number of species captured, while VLL had the lowest. Two economically and ecologically important species (Red Grouper Epinephelus morio and Red Snapper Lutjanus campechanus) were common to all four gear types, and the size selectivity of these two species generally overlapped. However, significant differences among gear types were detected. Unimodal selection curves for hooked gears indicated that size of Red Snapper and Red Grouper increased as hook size increased. These data provide insight on species and size selectivity of multiple gears, which will contribute to future survey design and aid in the management of reef-fish populations.