Oculina Banks: Habitat, Fish Populations, Restoration, and Enforcement

The shelf-edge Oculina coral reef ecosystem, known only from off the central east coast of Florida, is unique among coral reefs and exists nowhere else on earth. The azooxanthellate (i.e., lack symbiotic algae) branching coral typically produces 1 – 2 meter diameter coral heads which often coalesce into thicket-like habitats with exceedingly high biodiversity, similar to that of tropical coral reefs. Historical accounts indicate very high densities of economically important reef fish as well as grouper spawning aggregations associated with the coral habitat. The uniqueness, productivity, and vulnerability of the Oculina habitat moved the South Atlantic Fishery Management Council (SAFMC) in 1984 to declare a significant portion (92 nmi2 ) of the habitat an HAPC. This legislative action purportedly protected the coral from trawling, dredging, and most other mechanically disruptive activities. Evidence of demographic impacts of fishing on grouper spawning aggregations further stimulated the SAFMC in 1994 to close the original HAPC for a period of 10 years to bottom fishing as a test of the effectiveness of a fishery reserve in protecting the reproductive capacity of groupers. Further expansion of the original HAPC to cover 300 nmi2 was instated in 2000. A 1995 submersible survey suggested that much of the habitat, the economically important fish populations, and the grouper spawning aggregations described in the 1970s were decimated by 1995. A broad-scale submersible and ROV survey conducted in September 2001 found that most (90%) of the Oculina habitat within the EORR is reduced to an unconsolidated rubble and the damage north of the EORR may be greater. To our knowledge, only about 8 hectares (20 acres) of fully intact Oculina thicket habitat remain in the OHAPC and probably in the world. Restoration experiments were run from 1996 to 1999 to evaluate the transplantation potential of Oculina. High rates of transplant survival induced NMFS to support a significant restoration effort in 2000 and 2001. Results of the restoration efforts of 2000 indicate that restoration structures designed to simulate Oculina habitat are attracting groupers, snappers, and amberjack, and may be sites of grouper spawning aggregations. Oculina habitat and fish populations within the EORR were described quantitatively (expressed in terms of density, nos./hectare) using a system of two cameras with attached lasers. Although fish populations observed in 2001 were not directly comparable to those observed in 1995, there was a noted increase in grouper numbers and size and especially an increase in the abundance of males of gag and scamp, suggesting the reoccurrence of spawning aggregations of both species. Juvenile speckled hind were observed in Oculina thickets, suggesting a nursery function for this species. Evidence is very strong that shrimpers are still illegally trawling within the OHAPC, and suggestions are made to eliminate such threats to this vulnerable, but productive habitat. We have initiated work on a habitat map of the OHAPC and produced a protocol to continue habitat mapping.

To provide a report to the South Atlantic Fishery Management Council December 2001 on Oculina Banks: Habitat, Fish Populations, Restoration, and Enforcement