Changes in size over time and depth of three popularly fished species in Biscayne National Park

Effects of current fishing regulations and the possibility of depth refuge were explored in Biscayne National Park (BNP) for black grouper, gray snapper, and hogfish. In previous studies, all three species were seen to show ontogenetic shifts in depth. Fishing regulations were created for these fishes in the early to mid 1990s and have either seen increased minimum sizes (black grouper) or no change (gray snapper and hogfish). I used Reef-fish Visual Censuses (RVC) data from BNP from 1999-2016 to explore the effect of time and depth on the Lbar (average size of exploitable sized fish) of each species. I found that hogfish did not show an increased size between the first and last year or between the two depth strata. Gray snapper showed an increased proportion of exploitable fish in deeper strata and a decrease in Lbar between the first and last years of the study. Black grouper showed a relationship to a higher usage of deeper habitats at larger sizes but did not display a change in size from the first to last year of the study. The variability in the results can be explained by factors relating to life history, behavioral traits, current populations, and anthropogenic factors. Overall, populations do not seem to be faring well under current fishing practices and changes to regulations, the designs of MPAs, and enforcement will be important in protecting these species