PI Surname: Ault Project #: 2000-19 Region: Gulf of Mexico Title

NURC/UNCW Management Information System Project Summary Report PI Surname: Ault Project #: 2000-19 Region: Gulf of Mexico Title: Multispecies Reef Fish Stock Assessment in the Dry Tortugas Start Date: May 22, 2000 End Date: June 11, 2000 Principal Investigator: Dr. Jerald S. Ault. University o C Miami Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL J3 ) 149, [email protected], (305)361-4884 ph, (305)361-4791 fax Co-Principal Investigators: Dr. James A. Bohnsack, National Marine Fisheries Service, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, FL 33149, [email protected], (305)361-4252 ph Dr. Steven L. Miller, University of North Carolina at Wilmington, 515 Caribbean Drive, Key Largo, FL J3037, (305)451-0233, (305)453-9719, [email protected] Cooperating Institutions: Florida Keys National Marine Sanctuary, National Park Service, Florida Fish & Wildlife Conservation Commission Number of participants: Total number of science participants 27-; Total number ofNURC participants -2-. Contribution No: PRD-00/01-13 August 2000 Executive Summary This report documents the activities and preliminary findings of the Tortugas 2000 millennial expedition to assess reef fish and benthic communities in the Dry Tortugas region by a team of collaborating scientists from the University of Miami, NOAA Fisheries, University ofN orth Carolina at Wilmington, and the Florida Fish and Wildhfe Conservation Commission. These researchers are working closely with agencies that manage the Florida Keys National Marine Sanctuary and the Dry Tortugas National Park, conducting intensive baseline monitoring research on coral reef fishery resources and essential benthic habitats in an effort to help the FKNMS and National Park Service (NPS) pick from the Tortugas'600 square miles the best spots to provide protection from the effects of overfishing and habitat degradation. Currently, FKNMS and NPS recommendations are in place requesting that a 200-square-mile area in the Tortugas be closed to all fishing. To support these management efforts, from May 22 to June 11, 2000, the collaborating research team conducted a 3-week expedition using state-of-the-art survey sampling methods with innovative technologies to count and measure coral reef fishes and assessing benthic habitats on a research cruise funded jointly by the National Undersea Research Center and the FKNMS. During the 19 operational days of the 2000 cruise, the research team conducted 1, 1 22 scientific dives for a combined total of 2J.5 days underwater. This is in addition to a similar effort in 1999 which conducted another 1 OJ6 scientific dives. These two research expeditions have surveyed more than 230 species of fish and dozens of different corals and sponges over a vast area around the Dry Tortugas southwest of the Florida peninsula. The Dry Tortugas considered are a fragile marine frontier and a rich breeding ground potentially threatened by habitat degradation and fishing. Preliminary results of our research suggests that most exploited reef fishes (e.g., groupers and snappers) are being overfished. During the last two years of our spatially-intensive surveys in the Dry Tortugas region, we found that the number and size ofsought-after fish are down considerably from presumed historical levels. Grouper, for example, are down to approximately 5 to 10 percent of their historical spawning population sizes. That is a serious concern because the Tortugas region is widely considered where the fish spawn and then repopulate the rest of the waters around the Keys and South Florida. These results are consistent with the evidence for serial overfishing (i.e., the sequential loss of the most vulnerable species to fishing) we have documented throughout the Florida Keys in previous research. A distinct and alarming paucity of shark encounters was noted. We also noted frequent occurrences of shrimp trawl damage in the region that included obliterated habitats and coral draped in nets and cables. The research expedition also discovered new and unique areas of luxuriant coral reefs, and isolated pockets of incredible fish abundance and habitat richness. Areas of intense algal growth were seen, despite the region's relative isolation from human sources of eutrophication which suggests that physical oceanographic processes play a major, but little known, role in the dynamics of the region's productivity. We found that many of the reefs in the region are not unmapped, and prior to this work, virtually unknown. The findings of exquisite coral reefs and reef fishes in the Marquesas, a place where current maps erroneously indicate no reef exist, suggests that new vigor is required to build a more clear picture of habitats and fisher^y resources in the westemmost Florida Keys. Results from this research will provide critical scientific guidance necessary to facilitate design of a long-term prograrn for monitoring and assessment of economically and ecologically important reef resources. Results will also provide key information necessary to make rational decisions towards building sustainable fisheries while conserving marine biodiversity in the Dry Tortugas. iii PROJECT DESCRIPTION 1. Summary of Proiect. The Tortugas 2000 millennia] research expedition was sponsored by the National Undersea Research Center and the Florida Keys National Marine Sanctuary. The expedition was focused on exploration and assessment of populations of multispecies coral reef fish stocks and co-mapping of essential and unique habitats during early summer 2000 in one of the United States' last marine frontiers, the Dry Tortugas. Sometimes called "Florida's Yellowstone", the Tortugas helps support the multibillion dollar fishing and tourism industry in the Florida Keys. During the latter part of the 201h century, populations o fa number o fcoral reef fish species in the Dry Tortugas, Florida Keys, and in the Gulf of Mexico have steadily declined due to heavy fishing pressure and habitat loss. The Tortugas region, renowned for its luxuriant coral reefs and spectacular beauty, has a coral reef fish community comprised of more than 230 species inhabiting a 600-square-mile area. The Tortugas region continues to be heavily exploited despite its remote location 70 miles west of Key West (Figure 1). Figure 1.- Three-dimensional maps of the Florida Keys coral reef ecosystem showing: (top panel) South Florida and the coral reef tract (red) from Key Biscayne to the Dry Tortugas; and, (bottom panel) Dry Tortugas National Park habitats and fish sampling where blue balls indicate primary sampling units for reef fish during May-June 2000. I Reef fishes are an essential and conspicuous component of the South Florida marine ecosystem that support important commercial, recreational, and aesthetic uses throughout the region. They are the ultimate 'down-stream integrators' of environmental conditions and human activities that altimately affect coral reef population productivity and stability. Notably, factors that increase population mortality, such as pollution, fishing, and loss of habitat are eventually reflected in fish stock abundance, and individual size and condition. Concern about habitat degradation and escalating resource use resulted in the establishment of the Florida Keys National Marine Sanctuary (FKNMS) in 1990 and new avenues of management planning by NPS for Dry Tortugas National Park. Over the past several decades, public use of and conflicts over fishery resources have increased sharply in the Florida Keys, while some fishery catches from historically productive snapper and grouper stocks have declined. Ault et al. (1997, 1998) used fishery-independent data in a quantitative retrospective assessment of the Florida Keys multispecies reef fish community and showed that fishing mortality levels are very intense, that many stocks are "overfished" and exploitation has altered the structure and dynamics of the reef fish community. Since the late 1970s the reef fishery has shown signs of overfishing. FKNMS and NPS are now augmenting traditional fishery and habitat management practices with marine reserves. Past practices have resulted in grouper spawning stocks at only 10 % of their previous population levels from the 1930s and 1940s. Overfishing in the Tortugas not only affects the current populations of reef fish species in the area, but also impacts other fish species throughout the Keys that travel to spawn in the coral and seagrass habitats around the Dry Tortugas. Many reef species are caught before they can spawn. Gulf Stream currents carry the eggs, larvae and juveniles of those fishes that do make it from the Tortugas spawning grounds east and north to appropriate nursery habitats throughout the Keys and southern Florid& An integrated reef fish and benthic habitat assessment survey in the Dry Tortugas was led by Drs. Jerald S. Ault, James A. Bohnsack, and Steven L. Miller, during late May to mid-June 2000, to address these issues and establish a quantitative baseline of reef fish and habitat resources against which system changes and management performance can be measured. Currently, FKNMS and NPS recommendations propose that a 200-square-mile area in the Tortugas be closed to all fishing. GoalsI and Objectives The overall research goal for the Tortugas 2000 millennial expedition was to quantify the spatial distribution, abundance and size structure of the coral reef fish community prior to implementation of an marine reserve in the region that includes waters managed

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