IMPACTS OF BOTTOM TRAWLING ON A DEEP-WATER OCULINA CORAL ECOSYSTEM OFF FLORIDA

摘要

In 1984, a portion of the deep-water Oculina coral reef ecosystem off eastern Florida was protected as the Oculina Habitat Area of Particular Concern (OH APC), prohibiting bottom trawls, longlines, dredges, and anchors. Unfortunately, the northern two thirds of the reef system remained open to these gear until 2000 when the OHAPC boundaries were expanded to 1029 km~2. In the 1970s, the Oculina reefs were teeming with large spawning aggregations of grouper and snapper. By the early 1990s, commercial and recreational fishing had decimated the fish populations, and the coral had been severely impacted by bottom trawling for rock shrimp. Historical photographic transects, taken in the 1970s with the Johnson-Sea-Link sub-mersibles, provide crucial evidence of the status and health of the reefs prior to heavy fishing and trawling activities. Quantitative analyses of photographic images by point count reveal drastic loss of live coral cover between 1975 and 2001. Six coral reef sites had nearly 100% loss of live coral, whereas only two reefs which were within the boundaries of the original OHAPC since 1984 survived and were not impacted by trawling. Management and conservation plans for deep-sea coral reef ecosystems worldwide must be based on sound scientific understanding as well as adequate surveillance and enforcement; this study will help build a foundation for this understanding.