Abstract
Biological data collected over multiple, consecutive years can be an incredibly useful tool when attempting to analyze change over time. Data from long-term monitoring is in fact necessary to explain patterns of decline and recovery in the interest of informed management action. The National Park Service South Florida/Caribbean Network (NPS SFCN) has been monitoring vital natural resources in Virgin Islands National Park (VIIS) since the 1980s to provide park managers with information on the ecological health of the park. Of interest to park managers is data on fish and benthic communities that give insight into how coral reef ecosystems in VIIS are responding to disturbance. VIIS has faced decades of overfishing leading to reductions in top predators and large-bodied species, hurricanes that have wiped out coral habitat, bleaching that has led to significant reductions in live coral cover, and coral disease. Given that continued monitoring has been going on for decades at the same four sites in VIIS, this project used data from fish and benthic surveys to examine trends over time of benthic and fish populations, as well as look for relationships between the two to illustrate how one may be affecting the other. The metrics chosen to compare were biomass of fish and percent cover of the benthos, specifically live stony coral, macroalgae, and turf algae. Fish biomass was further divided by trophic group, as well as by family and by species. Analysis of the data found that while coral cover was negatively affected by disturbance, fish biomass increased over time at all four sites. Increased biomass was likely driven by smaller to intermediate sized fish species, since largebodied species had not been observed for a very long time. Increased coral cover was correlated with decreased biomass of herbivores and secondary consumers which may imply that the benthos does have an effect on fish assemblages, but it is impossible to confirm that there is a relationship due to covarying factors. Inclusion of structural complexity or analysis on fishing activity may help better understand the observed relationships. However, continued annual monitoring and refinement of variables is recommended to determine the ecological health of an ecosystem that is vulnerable yet incredibly vital in the face of ongoing disturbance.