Preliminary Survey of the Marine Fishes of Southeast Florida
Principal Investigator: Richard Spieler, Ph.D.
The ability to determine change in an environmental resource in response to any anthropogenic or natural activity, requires an accurate inventory of that resource prior to the activity occurring. The resources of interest to this study are the coral reef fishes of Broward County, Florida. The coral reefs and coral-reef fishes in this area, residents and transients, are subject to multiple environmental insults including: heavy fishing pressure, effluent from Ft. Lauderdale and Port Everglades, and habitat destruction from anchoring and ship groundings. Multiple local, state, and federal management decisions are being implemented, or considered, to alleviate the current situation or to mitigate damage. Without the knowledge of current stocks, the effects of these decisions on local fish stocks will be speculative. In addition, we can continue to anticipate that a variety of unpredicted natural or anthropogenic factors will affect local fishes (e.g., hurricanes, epizootics). Likewise, it will be impossible to evaluate the full extent of damage from these phenomena without baseline data for comparison.
Project and Findings
The inshore environment of Broward County, Florida consists of three coral reef/hard bottom reef tracts, separated by sand substrate, running parallel to the coast in sequentially deeper water. At quarter nautical mile intervals, for an 18 nautical-mile coastline section, fishes were censused at western, eastern, and crest edges of each of the three reef tracts. On SCUBA, using the Bohnsack-Bannerot point count method, fish abundance, species richness, sizes, and general habitat characteristics were recorded. During a 4-year period, August 1998 to November 2002, 667 count sites were censused.
A total of 86,463 fish belonging to 208 species (52 families) were recorded. Significant differences in total abundance, species richness, and biomass were noted among the three reef tracts. There were significantly greater species richness and fish abundance on the offshore reef tract than on the middle tract, which, in turn, had greater richness and abundance than the inshore reef tract. The offshore reef had significantly higher biomass than the inshore reef tract, which, in turn, had significantly higher biomass than the middle reef tract. The juvenile grunts, an important forage base, were significantly higher on the inshore and middle reefs, which did not differ significantly from each other, than the offshore reef. Of immediate management interest, the results include a surprising scarcity of legal size groupers (19) and snappers (198) over the entire survey area.
Implications for Management
This is the first comprehensive survey of the coral reef fishes of Broward County. As such, it will provide a baseline database with which to compare future change in the local fish assemblage in response to anthropogenic or natural causes.
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