Abstract

Understanding the spatiotemporal relationships of reef fish communities can aid in applying ecosystem-based management principles. Reef fish communities of the U.S. Virgin Islands (USVI) fall under the management purview of the USVI Department of Planning and Natural Resources (DPNR) and NOAA. Management actions and laws are based on territory-wide catch estimates and fishery independent data sets and are therefore applied equally across the three islands of St. Thomas, St. John, and St. Croix. However, fishing practices and intensity differ on St. Croix and a significant distance separates it from St. Thomas and St. John. A multivariate analysis of synoptic fishery-independent reef fish data revealed separation of reef fish communities between St. Thomas and St. Croix. For some species this difference could be fisheries-related. However, non-targeted species and communities also varied significantly within similar habitats, suggesting potential ecological impacts. While both islands possess similar reef habitats (e.g., deep shelf edge reefs, shallow nearshore reefs), these habitats are distributed across a more extensive shelf area on St. Thomas. Reef fish communities differed significantly along a nearshore to offshore gradient while St. Croix reef fish communities did not, suggesting that shelf size may also be influencing reef fish community composition and distribution. These results suggest that reef fish community composition is controlled by the combined effects of resource extraction and biophysical variability.

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