NCCOS Project Explorer (NPE)

Characterization of the Tortugas Ecological Reserve: Establishment of a Baseline and Measurement of the Effect of Establishment of a Reserve (2004)

Project Description:
The overall objective of CCFHR’s surveys in the Tortugas is to examine the effects of implementation of the Tortugas North Ecological Reserve (TNER) on the coral reef ecosystem it was designed to protect. While the establishment of the reserve in 2001 will reduce a variety of human impacts, the banning of all fishing and consequent creation of a refuge for recreationally and commercially exploited communities is expected to have the greatest long term impact within the Tortugas and adjacent systems. Historically, heaviest exploitation has focused on fishes and lobster of the Tortugas reefs and crustaceans that live to the north of the banks on the soft bottom shelf. Exploited reef fish are large predators, primarily members of the snapper/grouper complex that are exploited by hook and line, long-lines and traps. The most important crustacean of the shelf, the pink shrimp is caught with trawls. Fishing activity can alter habitat structure physically but the impact of fishing on trophic structure of the ecosystem is likely to be of particular importance. The condition of the reef fish predator community and shelf soft bottom community can be expected to have a profound impact on the coral reef ecosystem as a whole. These coral reef banks and surrounding softbottom shelf are ecologically linked. Energy and nutrients are imported to the reef by reef fish that feed nocturnally in the adjacent sand, algae, and seagrass flats (Meyer, et al. 1983). Much of the TNER consists of soft-bottom shelf habitat and previous work on the west Florida shelf suggests that benthic primary production is the major energetic source supporting fish biomass (Currin et al. 2000). The crustacean and other abundant member of the shelf community transform this benthic primary productivity to a form useful to reef carnivors. Thus the animals of the soft bottom, as important prey of the nocturnally migrating reef fishes make the primary productivity of the shelf available to the reef community of the banks. Increases in the biomass of predaceous fishes should increase this flow of energy between reef and soft bottom. In addition increased predator biomass on the reef is expected to impact underlying trophic levels through increased mortality rates and behavioral impacts on reef and soft bottom prey species. Cascading effects of these direct impacts are expected to indirectly impact corals and other sessile benthic communities. Populations of targeted species and their impact on the ecosystem is expected to vary relative to geographic variation in management restrictions. Highest abundance of predatory fishes is expected in the TNER where all fishing has been prohibited, intermediate abundance would be expected in the Dry Tortugas National Park (DTNP) where harvest is limited to recreational hook and line fishing, and lowest abundance would be expected outside these jurisdictions in the Exclusive Economic Zone (EEZ) where federally sanctioned commercial a

Expected Outcome:
This project will provide scientists, managers and the general public with a variety of data to evaluate the post-implementation effects of the Tortugas North Ecological Reserve. It will also evaluate a number of evolving technologies (e.g. multibeam sonar, split-beam sonar, georeferenced remote video groundtruthing) that can be applied to the evaluation of the long term effects of marine protected areas in general.