Thirty Years of Change in Reef Fish Communities in the Florida Keys: The Importance of Habitat, Protection, and the Long-View

The Florida Keys reef tract contains a suite of important communities, but there are indications that human activity has dramatically altered these communities. Historical data have documented declines in trophy fish size and live coral cover, but these datasets often lack spatial and temporal resolution. As the management focus in marine systems shifts to ecosystem-based management, more precise data on the status and trends of these communities are needed. We use data from NOAA’s long-term reef visual census reef fish monitoring program to examine trends and changes in reef fish communities over the past 30 years. We found a variety of trajectories for different species and functional groups, including increases and decreases in abundance.  For some species, trajectories were strongly influenced by MPA protection, but others showed no response to MPA implementation. Despite the variety of single-species patterns, multivariate analyses shows that reef fish communities have been changing in a clear and consistent manner over the past 30 years, and that these patterns differed significantly between MPAs and unprotected areas. Our data suggest that different factors drive these patterns for different species, and include loss of live coral and decline of species directly or indirectly dependent on live coral habitat, and slight recovery of the most heavily targeted fishery species, likely resulting from MPA protection. Despite the increase in abundance of some commercial species, the Florida Keys is still a heavily exploited ecosystem that requires improvements in management, including expansion of MPAs, and a long time frame to restore these communities.