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 by the NPS and FKNMS. To accomplish this goal our objectives were:

(1) To jointly conduct a spatially-intensive visual census of the multispecies coral reef fish community and representative benthic coral reef habitats in the Dry Tortugas region.

(2) To use these survey data to conduct baseline multispecies stock assessments of reef fishery resources prior to implementation of proposed marine reserves in the Tortugas.

(3) To investigate patterns of spatial variation among coral reefs and reef fishes to develop an

2 efficient survey sampling design and longer-terin monitoring strategy that improves the basis of management for fisheries and essential habitats in the Dry Tortugas.

Methods The Tortugas 2000 expedition surveyed an area of approximately 450 far" (Figures I & 2), during which about 884 reef fish and 152 benthic habitat samples (science dives) were made (Table 1) to provide a quantitative baseline assessment of the distribution and status of fishery resources and their essential habitats in the Dry Tortugas region. Spatially-intensive sampling was conducted across the region in Dry Tortugas National Park, Tortugas and Little Banks, and Riley's Hump. In addition, pilot survey dives were also made in the previously unexplored Marquesas region on return cruise legs. The research "team" consisted of a group of 27 collaborating marine fishery scientists and ecologists, 2 mission support personnel from the National Undersea Research Center (NURC), plus 2 captains and 2 crew from the M/V Spree (Table 2). The reef fish assessment team was comprised of 22 scientists from the University of Miami's Rosenstiel School of Marine and Atmospheric Science, NOAA Fisheries and FKNMS, NOVA Southeast University, and the Florida Fish and Wildlife Conservation Commission, led by Drs. Ault and Bohnsack. Concurrent sampling of reef "habitat" community structure and spatial patterning was conducted by 4 benthic assessment team inembers from the NURC-Florida Keys Program, led by Dr. Steven Miller.

Table I.- Dry Tortugas region sampling (numberof sciencedives) forcoral reef fish and coral habitats during the 1999 and 2000 expeditions. DTNP is Dry Tortugas National Park.

CORAL REEF FISHES BENTHIC HABITATS Tortugas Riley's Tortugas Riley's Year DTNP Bank Marquesas Hump Totals DTNP Bank Marquesas Hump Totals

1999 378 360 133 70 941 73 69 26 13 181

2000 500 320 64 0 884 86 55 11 0 152

TOTAL 878 680 197 70 1825 169 124 37 13 333

Total Science Dives 1999-2000 = 2,158

The 1999 and 2000 Dry Tortugas studies significantly increased the spatial coverage of sampling. Representative habitats for all size groups of fish species were included. We substantially refined the estimates of reef fish abundance and size structure derived from the survey by using "habitat" types as auxiliary covariates of reef fish abundance. Results from this research will provide critical scientific guidance necessary to make prudent decisions on the nature and extent of spatial management alternative boundaries, such as marine reserves proposed by FKNMS and the National Park Service.

3 TABLE 2.- List of Participants in NURC Mission 2000-19 (GOM): Multispecies Coral Reef Fish Stock Assessment in the Dry Tortugas May 22 - June 11, 2000

(A) SCIENCE PERSONNEL

Personnel Role Institution

I Dr. Jerald S. Ault Chief Scientist Univ. Miami RSMAS 2 Dr. James A. Bohnsack Co-Principal Investigator NOAA Fisheries 3 Dr. Steven Miller Lead Benthic Team IJNCW 4 Dr. Jlangang Luo Reef Fish Assessment Univ. Miami RISDMAS a Dr. Steven G. Smith Reef Fish Assessment Univ. Miami RSMAS 6 Dr. Geoffrey A. Messier Reef Fish Assessment Univ. Miami RSMAS 7 Diane W. Swanson Benthic, Habitats UNCW a Mark Chiappone Benthic Habitats UNCW 9 Dr. James Colvocorresses Reef Fish Assessment Florida FWC 10 Tahzay Jones Reef Fish Assessment Univ. Miami RSMAS I I Dr. Anne-Made Eklund Reef Fish Assessment NOAA Fisheries 12 Jack Javech Reef Fish Assessment NOAA Fisheries 13 James Kidney Reef Fish Assessment Florida FWC 14 Stephanie Bolden Reef Fish Assessment NCAA Fisheries 15 Guy S. Davenport Reef Fish Assessment NOAA Fisheries 16 Amel Saied Reef Fish Assessment Univ. Miami RSMAS 17 Mike Larkin Reef Fish Assessment Florida FWC 18 Erik Franklin Reef Fish Assessment NOAA FKNMS 19 Joe Contillo Reef Fish Assessment NOAA Fisheries 20 Stacy Luthy Reef Fish Assessment Univ. Miami RSMAS 21 Helena Molina Reef Fish Assessment Univ. Miami RSMAS 22 Allison I/Witte Berithic Habitats UNCW 23 Douglas Harper Reef Fish Assessment NOAA Fisheries 24 David McClellan Reef Fish Assessment NOAA Fisheries 25 Brian Ettinger Reef Fish Assessment NOVA SE Univ. 26 Mike Judge Reef Fish Assessment NOAA Fisheries 27 Jennifer Schull Reef Fish Assessment NOAA Fisheries

(B) NURC Personnel

Personnel Role Institution

I Lance, Hard Mission Coordinator UNCWNURC 2 Jennifer Dorton Technician UNCWNURC

Visual Census of the Tortugas Reef Fish Community Biological data from the Dry Tortugas reef fish sampling surveys were collected by standard, non-destructive, in sitzi, fishery-independent, visual monitoring methods by highly trained and experienced divers using open circuit nitrox SCUBA. The investigators were uniquely qualified to conduct this research based on past research and experience in the study area. This sampling survey employed a spatially-intensive two-stage stratified random reef fish visual census and coral reef

4 habitat assessments. "Live-boating" was conducted from the custom 100 fl dive vessel M/V Spree. NURC vessel support and other key pieces of high-tech equipment for deepwater reef fish assessment greatly facilitated the innovative scope and productivity of this scientific research effort. Visual methods are ideal for assessing reef fishes in the Dry Tortugas and Florida Keys because ofprevailing good visibility and management concerns requiring the use of non-destructive assessment methods. The field sampling effort required was rigorous to meet our objective of developing the quantitative habitat linkages necessary to ensure that the sampling effort provided cost-effective and statistically precise estimates of reef fish abundance and spatial distribution. Our spatially-intensive study employed a two stage stratified random survey design to optimize the sampling effort and to choose sampling locations, and is illustrated for the DTNP and Tortugas Bank in Figure 2.

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Figure 2.- Illustrated sample stratification strategy. The top panel shows cross-shelf (N to S) bottom features used for habitat classification. Middle two panels show superimposed grid overlays on (A) Dry Tortugas National Park, and (C) Tortugas and Little Banks showing randomly selected primary dive subunits (blocks). The bottom panels (B&D) show example blocks with replicated two-man dive team sample sites and UNC Wilmington coral team sample sites.

5 The Tortugas region sampling domain was partitioned into unique "habitat" strata based on geographical location and benthic habitat characteristics. We defined five geographical regions west of Key West: Marquesas Reef Tract, Rebecca/Isaac Shoals, Riley's Hump, Tortugas Bank, and Dry Tortugas National Park. Habitat within regions was partitioned into five reef-type categories: inshore reefs, patch reefs, platform reefs, fore reefs, and deep reefs, which covered the range ofrepresentative habitats. In design of the quantitative two-stage stratified random sampling survey, the sampling domain is overlain in a Geographical Information System (GIS) with a grid of I km2 cells. Each cell contains 25 blocks of 200 x 200 m which are the primary sample subunits. Each block that contains reef habitat is assigned a unique number and randomly selected for sampling from a discrete uniform probability distribution to ensure that each block has equal selection probability. Second stage sample stations are then randomly positioned on appropriate habitat in each block. There are 226 non- overlapping possible 7.5 m radius fish sampling stations within each block. Because of concerns about autocorrelation and safe diving practices, each fish sampling station consists of the average of combined stationary point estimates from two individual divers (i.e., a "buddy pair"). Primary sampling units were allocated to strata according to stratum area and variance of fish density for a representative suite of species. This ensured synoptic geographical coverage of the Dry Tortugas region. and also ensured sampling of representative reef habitats within each region.

Reef fish data are collected by a stationary diver centered in a randomly selected circular plot. The circular plot method is non-destructive and provides reliable quantitative estimates of species composition, abundance (densityper plot), frequency-of-occurrence, and individual size composition for the reef fish community. Divers sample 7.5 m radius circular plots for 5 minutes attempting to count all fish observed within each imaginary cylinder extending from die bottom to the limits of vertical visibility (usually the surface). Divers begin each sample by facing in one direction and listing all species within the field of view. When no new species are noted, new sectors are scanned by rotating in one direction for the 5 min period. Several complete rotations were usually made for each plot. After the initial 5 min, data are then collected on the abundance and minimum, mean, and maximum lengths for each species. Depth, bottom composition, estimated percentage cover, arid maximum relief are recorded for each plot from the polar perspective of the centrally located observer. An all purpose tool (APT), consisting of a ruler held out perpendicularly at the end of a meter stick, is used to reduce apparent magnification errors in size estimates. We have also designed and deployed an innovative state-of-the-art digital laser video camera system for increasing the precision of the process for both sizing and counting reef fish species. The technical methodology is being calibrated against standard divers using the visual census methods and APT meter sticks. In usual operations, divers periodically calibrate their sample radius estimates with the meter stick or fiberglass tape. Species with few individuals (e.g. angelfish, barracuda, hogfish) are counted and size estimated immediately. Highly mobile species that are unlikely to remain in the area (e.g. sharks, carangids, Clepticusparrai) are tabulated when first observed and then ignored. For common species (e.g. damselfish, wrasses, etc,) one 360' rotation is made for each species by working back up the Est in reverse order o frecording to reduce potential bias by avoiding counting a species when they were particularly abundant or obvious. The time required to record each sample averages 15-20 min (range 5 - 30), depending on the habitat.

6 To that end, in collaboration with our bembic habitat colleagues at UNC Wilmington, we have developed a "new" reef fish visual census data sheet that also includes a diver assessment of the reef habitat environment. The diver visual habitat assessment has three main attributes: abiotic footprint, biotic cover, and surface relief coverage. The abiotic footprint concerns the percentage of the visual 'cylinder' that contains sand, hardbottorn and rubble. The biotic cover focuses on the sand and hardbottom portions of the abictic footprint. Divers must determine the dominant biological cover in terms ofbare, algae, seagrass, corals, octocorals, and sponges. Finally, the diver assesses the relief within the cylinder in five height categories ranging from 0.2 ar to greater than 1.5 m. The important thing to note is that visual diver estimates of 'habitat' converged very rapidly, and the fish divers began to "see" the coral reef environment much in the same way as the benthic habitat specialists. We plan to use this extensive database in a sophisticated statistical analysis of fish-habitat relationships to improve fish abundance estimates and to generate cost-effective sampling designs.

Benthie Community Assessments Benthic community assessments were strategically integrated with the reef fish sampling effort allocations to optimize the performance and provide maximum structural coherence ofboth fish and habitat surveys. A detailed project summary report was prepared by the benthic assessment team and is provided in Appendix 1. Benthic communities were sampled using several methods: percent cover of benthic organisms via the linear point intercept method^ hard coral colony size and condition measurements; quantification of juvenile hard coral abundance; gorgonian abundance and species richness; and species richness of sponges and hard corals. Video surveys were also conducted to quantify topographic complexity and to produce an archival record of each site. These methods allow us to obtain a relatively "rapid" and accurate picture of each site studied. There is little historic information available about the benthic communities in this region, and most previous surveys have focused on shallower (< 10 m) hard-bottom and reef habitats within Dry Tortugas National Park. Characterizing benthic communities along with fish censuses, on multiple spatial scales, is particularly important and timely as the Tortugas 2000 program advances.

Distribution of Diver Sampling Effort The spatial distribution and intensity of reef fish and benthic community sampling effort is shown for 1999 and 2000 (Figure 3). During the 1999 and 2000 Dry Tortugas sampling surveys we collected over 2100 visual point samples in the Dry Tortugas region. Each year's survey was conducted over relatively short time periods (i.e., 3-4 weeks) to provide a spatially integrated "snapshot" of the exploited reef fish community (cf., Table 1). At each site we characterized habitats for nursery value, developed spatially-explicit estimates of abundance and biomass by size (age) groups for major species, evaluated the effects of exploitation, and considered longer-term cost- effective sampling designs for assessment and management of these critical resources. We also used a CTD to record surface and bottom water temperatures, salinity, and dissolved oxygen. A small underwater camera was lowered to the bottom at each site to collect a digital video record ofbenthic habitats that can be compared to diver estimates. Reef fish diver samples were transferred to a digital database directly after sampling using the innovative RVC graphical user interface computer program.

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Figure 3.- Summary of spatial ly-i ntensive two-stage stratified random sampling in the Dry Tortugas region conducted during the 1999 and 2000 NURC-sponsored surveys of coral reef fish and habitats. Primary sites for fish visual sampling are shown as magenta circles with dots (2000) and light purple circles (1999), while coral habitat sampling sites are shown as yellow circles with dots (2000) and yellow circles (1999).

11. Summary of Results (A) Pretiminary results and significance. Our research employed a systems approach to develop high precision estimates of reef fish abundance, size structure, and community composition from a collaborative spatially-intensive, fishery-independent sampling survey of reef fish and coral reef resources. Preliminarily estimates indicate that the reef fish assessment team sighted more than 230 reef fish species during dives at over 1000 unique sampling sites and 2500 diver point counts in the Dry Tortugas region (Table 3).

During the NURC-sponsored cruise(s), we were able to identify and sample a variety of new coral reef environments in the DryTortugas regionusing principally diver visual census surveys of reef fish and diver-based rapid assessment of reef "habitats".

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Table 3.- List of families (48) and species (230) of reef fishes observed in visual census samples from the Dry Tortugas by University of Miami RSMAS, NOAA Fisheries, and Florida Fish & Wildlife Conservation Commission divers.

9 The fish survey data produced relatively precise statistics on the status of exploited and non- exploited fish stocks in the reef fish community. These can be displayed in a dashboard array to reflect condition and dynamics of the stocks for a great number of exploited fishes including, 14 species of groupers, 10 snapper species, 3 species of hogfish, 15 species of grunts, barracuda, permit, nurse sharks, jacks arid mackerel (Tables 4). The airplane-like "dashboard" displays of species abundance, size and spatial distributions can be used to detect changes in population size and the effects of exploitation. For example, preliminary estimates of fishing mortality on groupers, for example, shows that the average size of fish in the exploitable phase for black and red groupers translates (following Ault et. 1998) into instantaneous fishing mortality rates of 0.49 and 0.40, respectively, for the Tortugas region. From a fishery management standpoint that means that black and red grouper in the Tortugas experience fishing mortality rates that are 3.3 and 2.2 times the level that produces maximum sustainable yields. Practically speaking, the black and red grouper stocks in the Tortugas region are estimated to be at 9% and 28% of their historical spawning population sizes, respectively. This suggests that even when viewing the Tortugas as a single unit (which is not technically realistic given the unit stock definition), black and red grouper in the Tortugas are overfished according to federal standards. Technically, we could compute these statistics for all 230 species of fish seen in the Tortugas visual survey. Subsequent analyses of these data will produce relati,17ely accurate stock assessments, plus a new generation of accurate digital maps that document the spatial distribution, abundance and status of the reef fish community and essential habitats. Of note, ourmonitoring and assessment strategy found substantial evidence of severe "serialoverfishing" in the Tortugas region, a finding that is entirely consistent with our broader assessment of the Florida Keys, despite the Dry Tortugas' relatively great distance from the more populated areas of the Keys. One surprising finding was that divers encountered signs of trawling in coral habitats and remains of at least three shrimp nets each year. This was a surprisingly large number of shrimp nets considering the total number of randomly selected points sampled. Evidence of trawling in coral is an obvious management concern.

We also encountered a rich biodiversity of fishes and corals. Hydro acoustics were used in an innovative way to assess reef fishes. We observed significant biomass for small pelagic organisms that appear in the water column over the reef during 'dark' hours (i.e., not present during daylight hours) that may be derivative of reef productivity, and are likely a key factor in coral reef trophodynarnics that supports reef fish biomass. We also encountered substantial evidence of recruitment to habitat-types that were previously unrecognized in the scientific literature. For example, we noted significant use of"gorgonian-forest" habitats by the young of the year andjuvenile groupers, snappers, grunts, parrotfishes, butterflyfishes, hamlets and surgeonfishes. We also "discovered" and expanded known areas of luxuriant coral coverages: (1) a large 75 Mi2 area of 'Sherwood Forest'-type habitat that extends along the western Tortugas Bank that is 20 to 30 times greater than the area previously recognized; and, (2) an area we call 'Loggerhead Forest'that covers about 8 mi^ inside the western boundary of Dry Tortugas National Park.

10 Dry Tortugas 2000 Two-Stage StRS Sampling 7127/00 16:44 (n=170, nm=-326) Species Juv. CPUE SE(CPUE) p(nz) Lbar SE(Lbar) n fish p(nz)

Mutton Snapper 0.00142 0.00142 0.31% 48.67 2.145 19.5 8.28% Schoolmaster 0.00071 0.00071 0.31% 38.04 0.547 47 5,83% Gray Snapper 0.75392 0.26226 16.26% 33.23 0.386 236,75 21.47% Dog Snapper 0.00250 0.00250 0.31% 59.67 3.862 4 1.53% Lane Snapper 0,22489 0.16010 1.23% 25.66 0.269 139.875 1.53% Yeliowtail Snapper 2.66640 0.45844 55.52% 35.95 0.465 114.125 14.42% Mahogany Snapper 0.00000 0.00% 0.00 0 0.00% Hogfish 0.19213 0.05811 1258% 40.62 0.948 77.75 25.15% Cubera Sriapper 0.00000 0^00% 0.00 0 0.00% Blacklin Snapper 0.00000 0.00% 0.00 0 0.00% Groupers Rock Hind 0.01630 0.00542 3.99% 30.90 1 A22 10 4.60% Graysby 0.08212 Oo1477 14.72% 25.72 0.723 26.625 11.96% Coney 0.00284 0.00219 0.61% 25.00 0-000 1 0.61% Red Hind 0.01754 U0767 2.45% 29.92 3.393 6 2.76% Jewfish 0,00000 0^00% 240.00 0^000 0.5 0.31% Red Grouper 0,40147 0,0^31370 46.93% 59.67 0,899 29^625 15,95% Nassau Grouper 0.00775 0.00414 123% 55.00 0.000 0.5 0.31% Black Gmuper 0.16366 0.02690 1&37% 65.00 5.359 8,5 137% Yellowmouth Grouper O^00586 0.00340 1,23% 60.00 0.000 1^5 0.61% Gag Grouper O^00392 0.00287 0.61% 56.33 8.667 1.5 0.61% Scamp 0.09194 0.02363 1I.D4% 5750 0.000 1 0.61% Yellowfln Grouper 0,00782 0.00382 1,53% 0.00 0 0.00% Yellowedge Grouper 0.00211 0.00151 0.61% 0.00 0 0.000/0 Tiger Grouper 0.00213 0.00151 G.92% 55.00 0.000 0.5 0.31% Grunts Tonitate 27.28620 6.26555 24.23% 0.00 0 Oo0% Sailors Choice 0.00148 O^00148 0.31% 29.26 OSOI 37 0.92% White Grunt 3.92681 O.M54 50.61% 25.00 0.207 225.249 37.42% Bluestriped Grunt 0.01063 0.00905 0.61% 2(103 0.717 19.25 5.52% Porldish 0.04091 0.01224 3.68% 26.68 0,815 37.625 10.12% Black Margate 0.00000 0.00% 0.00 0 0.00% Margate 0.03132 0,02338 1.84% 33.83 1.097 26.5 I.a4% Caesar Grunt 0,00000 0,00% 23.00 1.581 2 0.92% Smallmouth Grunt 0,00000 0.00% 0.00 a 0.00% French Grunt 0.91159 0.64726 5.83% 25.29 0,351 52.375 4.29% Spanish Grunt 0.14238 0.14244 0.31% 26.93 1.701 7 3,07% Cottonwick 0.56785 0.42494 3.68% 0.00 0 0.00% Striped Grunt 0.06791 0.05337 0^92% 0.00 0 0.00% Saucereye Porgy 0.82351 0.09125 46.32% 25.62 0.371 129.25 38.65% Pigfish 0.00000 0.00% 2&50 0.000 1 0.61% Barracuda & Jacks Barracuda Oo1818 0.00794 2.15% 99.26 4.635 30.625 11.04% Yellow Jack 0.04747 0.03001 1.53% 43.73 1.804 11.625 2.15% BarJack 3.42096 0.95112 18.10% 37.60 0.314 266.541 9.20% Amberiack 0-00000 0.00% 0.00 0 0.00% Permit 0.00000 0^00% 0.00 0 0.00% Bermuda Chub 0.10441 0.06565 1.84% 41.47 0.708 147.25 4.60% Table 4, Preliminary summary statistics on exploited reef fish from the Dry Tortugas 2000 expedition.

I I In general, we determined that there actually is substantially more area containing coral reef habitats, particularly luxuriant reefs, than indicated by the current suite of digital habitat maps. Collaborative analyses are underway by our team to statistically "link" reef fish abundance, size distribution and community structure data with key features of the "habitat" and biophysical environment to build new, revised maps of benthic habitats. We expect that explicit modeling of linkages between fish cornmunity distribution and key "habitats" will provide critical guidance for future cost-effective sampling and resource assessment efforts.

In conjunction with the reef fish assessment study, we conducted coral reef habitat assessmpnts at about 20% of the sites sampled in the reef fish visual census. Sites were sampled at depths ranging from 10 to 30 meters, and in concert with the sample sites of the reef fish assessment team. Benthic surveys from all sites resulted in the identification of about eight broad "habitat" classes: low reliefhardbottom or rocky outcrops; with sand and rubble patches; lowreliefhardbottom areas dominated by algae and gorgonians; low relief, algal-dominated spur and groove reef, high relief. algal- and coral-dominated spur and groove reef-, shallow high-relief terrace; deep sand plain with patches of rubble and hardbottom; and deep reef terrace with rocky outcrops. These surveys vielded a rich biodiversity of benthic invertebrates including 41 species of hard corals (including 24 species of reef-building corals), 42 sponge species, and 26 octocoral species. Data on benthic community structure will be critical for assessing essential rishery habitat, evaluating proposed boundaries of no-take marine reserves, and establishing a baseline assessment for future evaluations.

Success of the mission in terms of project goals.

The 2000 inillennial expedition cruise was a smashing success in terms of ineeting project goals, and for getting the word out through National media channels. During the 2000 cruise we greatly exceeded our expectations for the number of diver samples made by accomplishing an unprecedented combined total of 1,164 science dives during the 19 operational days at sea in the Tortugas region (Tables 2 and 3). This feat was accomplished through an unparalleled combination of efficient planning for daily dive operations by the Principal Investigators and associated key scientists, in conjunction with exceptional operations support provided by the highly competent NURC technical staff, including the high caliber vessel operations and management by the captains and crew of the NI/V Spree.

National media coverage of the Tortugas 2000 millennial expedition cruise was exceptional. The resultant stories onthe links between our cruise objectives and the Florida Keys serial overfishing and reef degradation problems, and the need for implementation and assessment was exceptional. For example, CBS Evening News with Dan Rather aired a piece on June 8", 2000, documenting our research cruise and extent of serial overfishing of reef fish we've documented in the Florida Keys. In addition, a national Associated Press article by Brenden Farrington focused on our work in the context of the overfishing problems and the proposed implementation of marine reserves in the Dry Tortugas by the FKNMS and the NPS.

12 Plans for use of the data We expect to conduct further strategic follow-on analyses of the reef fish and habitat databases collected during 1999 and 2000 with the following objectives:

(1) To conduct model-based analyses to develop precise statistical models of fish-habitat associations that provide robust population estimates germane to stock assessments;

To facilitate these analyses, we are currently producing high quality VHS fihn of our digital video. Our ultimate objectives are: (1) to correlate these standardized data with relevant physical and biological structure in the area; and (2) to model the linkages between coral reef fish resource distribution and abundance with key habitat features and the environment.

(2) To develop precise design-based spatial estimates of the average size in the exploitable phase, juvenile recruitment, and population abundance and biomass for the multispecies reef fish community and to provide baseline assessment of multispecies reef fish resources in DTNP using emerging 'control rule alternatives'.

The "habitat" data will be used to investigate spatial variation and abundance arnong reef types in the Dry Tortugas region, and in comparison to those throughout the broader Florida Keys region. These analyses will likely reveal the importance of various attributes of the benthic community structure to the function and dynamics of reef fish abundance, recruitment and stock productivity, as well as greatly enhance our understanding of basic ecological processes in coral reef ecosystems.

(1) To develop an optimal sampling survey design for longer-tenn cost-effective sampling of critical reef fishery resources.

Data from our Tortugas survey efforts will be used in the immediate future for resource management by the Florida Keys National Marine Sanctuary, the National Park Service, the State of Florida, and regional Fishery Management Councils, particularly in development and evaluation of the configuration of marine reserves in the region. In the longer-term, the data will provide the much needed basis for a cost-effective and efficient approach to sampling and assessing reef fish stocks more broadly in the Florida Keys and similar coral reef areas.

Finally, several peer-reviewedjoumal publications are envisaged from these analyses: one on reef fish assessment in the Dry Tortugas region; one on reef fish sampling relative to habitat structure; one on the spatial variation in abundance and community composition ofcoral reef habitats; and, one on intercomparative analyses ofdigital video and human visual technique to census reef fish. In terms ofconnections with the international scientific community, Drs. Ault, Bohnsack, and Miller will travel to the 91h International Coral Reef Symposium in Bali, Indonesia, in late October 2000, to present their results on reef fish sampling methods, quantitative estimation approaches, and benthic assessments in the Dry Tortugas and Florida Keys. Drs. Ault and Luo will then present two more scientific papers on the 'integrated reef fish monitoring and assessment strategy' and the 'the digital laser video system for assessing reef fish populations' at the 3' World Fisheries Congress in Beijing, China, in November, 2000.

New research ideas or directions generated. Probably the most important outcome of this collaborative research program will be development of a state-of-the-art two-stage sampling strategy for the monitoring and assessment of coral reef fishes and benthic habitats. By using the covariance structure between fish species, sizes and abundance distributions we are able to maximize the precision of the survey estimates in a cost- effective way. Robust estimates of species/community distribution will continue to provide the important initial conditions for inputs to sophisticated spatial population-dynamic simulation models to assess the short- and longer-term efficacy of the design and implementation of marine protected areas in the Dry Tortugas. These methodologies will be widely transferable amongst members of the U.S. Coral Reef Initiative and the wider international reef science community.

Another important area ofresearch for applications involves the potential for use of synoptic assessment technologies for assessing reef fish communities (i.e., applications of digital laser video, acoustics). We experienced substantial difficulties using the current available suite of available digital mapping products because of their limited coverages in the Tortugas region, and the apparently large levels of inaccuracy. This was a substantial issue, as the design of efficient sampling surveys relies heavily on the availability of accurate maps that define all reef habitat-types. We expect to use our data in collaboration with NOAA scientists to develop a new suite of map products that define reef habitats. However, that is not to say that a more strategic approach in synoptic assessment of coral reef habitats is needed. Given that we don't even know where all the coral reefs are in the Florida Keys, particularly in the Tortugas and Marquesas regions, some serious effort must be put into using LIDAR and co-mounted hyperspectral scanners to identify and classify bathymetry, hard bottoms and coral cover to improve the efficacy of future survey efforts and to provide accurate assessments of reef fish resource distribution and abundance. These issues are critical to evolving spatial management efforts involving the implementation ofmarine protected areas mandatedby Presidential order. Finally, we hope to pursue innovative uses of hydroacoustic and optical technologies to determine the "in-reef' faunal component that makes itself available as pelagic biomass during dark hours of the day, and what it means to the sustainability of fisheries and the conservation of marine biodiversity.

Ill. Center Support NURC/UNCW support was essential to the success and outstanding accomplishments of this mission. The provision of the 100 ft MN Spree, an exceptional custom dive platform, was essential to conduct the breadth and scope of the critically needed field sampling. The highly-skilled Captains (Ken and Frank) and crew of the M/V Spree were vital in supporting our complex work load located at multiple sites and depth ranges in the relatively remote Dry Tortugas region. The use of the vessel to "live boat" divers was an essential ingredient to our success, but at the same time required exceptional vigilance by the NURC and M/V Spree dive support team and exceptional boat handling skills by the Captain of the vessel. The crew of the M/V Spree and our NURC support staff worked firelessly and with extremely professional demeanor to ensure that all operations ran smoothly and efficiently. The Spree's on-board facilities were critical for providing on-site support of computers,

14 hydroacoustics and other electronics gear.

The ship was equipped with Nitrox support that facilitated the number of deep repetitive dives that were conducted by the coral reef fish and habitat assessment teams (cf, Table 1). Expert technical assistancebyMr. Lance Horn, mission coordinator, and his assistant divemaster, Ms. Jennifer Dorton, provided a reliable backstop that allowed research divers to focus on their scientific missions unfettered by the tedium ofoperations. These superior arrangements greatly reduced diver fatigue,' minimized down time associated withrequired surface intervals, and greatly enhanced the capabilities and responsiveness of the scientists to their rigorous field studies in locations where no man or woman has dived before! The mission coordinator was of great help coordinating and trouble- shooting the complex SCUBA diving operations, and virtually ensured that the scientific operations ran almost flawlessly. Mr. Horn worked exceptionally well with the Principal Scientists to ensure things went as planned, and he maintained a meticulous record of all diving and extra-operational activities that was rigorous and complex in its scope. Lance efficiently coordinated operations between scientific divers, deck crew, and vessel Captain, and frankly, without Lance's extraordinary capabilities in planning, safety and unique operational insights we would have not been able to accomplish anywhere near the breadth and scope of science activities.

IV. Public Information Release In response to concerns about declining regional trends in reef fish stocks and coral reef habitat quality, The Florida Keys National Marine Sanctuary and the National Park Service have proposed the creation of about 200 mi^ of 'no-take' ecological reserves and research natural areas in Florida's Tortugas region. The Tortugas, because of their upstream location, are considered essential areas for supplying juvenile fishes to the Florida Keys and southern Florida. To learn more about the resources, a team of 26 research scientists from the University ofMiami, NOAA'sNational Marine Fisheries Service, the Florida Fish and Wildlife Conservation Corrunission, and the University of North Carolina at Wilmington has completed a series of cruises to the Dry Tortugas region to assess the quantity and quality of flsh assemblages and reef habitat. Divers, using non-destructive visual methods, completed 2158 dives and sampled about 450 sites in 1999 and 2000. Data were collected on fish composition, abundance and size and habitat type, biological cover, and condition. Sampling was augmented with the latest technology, including digital laser video cameras, remotely operated submersible vehicles, and split-bearn hydro acoustics. Preliminary results show richbiological diversityin the Tortugas but also signs of overfishing. Divers encountered approximately 230 species of fish, 41 hard and 26 soft corals, and 42 sponge species. The extent of luxuriant hard coral coverage was found to be much greater than previously believed. In particular, two extensive new reef areas were described. Extensive reef habitat covered approximately 75 mi' along the western Tortugas Bank, an area 20 to 30 time greater than previously recognized. Also, a lush 8 m17' reef named "Loggerhead Forest" was found inside Dry Tortugas National Park near Tortugas Bank. In addition, unmapped reefs were found and sampled in the Marquesas region of the Keys. One discovery was that many juveniles of economically and ecologically important species used "gorgonian-forests" to a much greater extent that previously documented. This finding indicates that "soft" coral habitats are perhaps more important to fisheries than previously thought.

15 Despite the remoteness of the Tortugas from the rest of the Florida Keys, preliminary data analysis showed some evidence of overfishing. A general absence of larger species and individuals was observed among exploited species, including grouper and snapper. Also, surprisingly few shark and barracuda were observed. Preliminary estimates of fishing mortality on groupers, for example, show that the average size ofblack and red groupers in the exploitable size range in the Tortugas are 3.3 ) and 2.2 times, respectively, the fishing mortality rates that produce maximum sustainable yields. Some evidence of shrimp trawl damage to coral reefs was also found. Data collected from this research are being used to assess current conditions and to evaluate long-term changes in the Florida Keys National Marine Sanctuary and Dry Tortugas National Park. Changes are anticipated as the result o festablishing proposed marine reserves and other management measures. Data will be used to model linkages between fish community distribution, abundance and size structure in relation to key habitat characteristics. The models will allow better prediction of resource changes resulting from natural events or human activities. Results also will provide guidance for more cost-effective sampling in the future for resource assessments in the Florida Keys and other coral reef ecosystems. Data collected will be used by the Sanctuary, Park Service, and federal and state fishery management agencies to better manage resources in the Tortugas. Ultimately, the information obtained from this research will be used to determine the optimal design of marine reserves for building sustainable fisheries while consen.ring marine biological diversity.

Contacts: Professor Jerry Ault, University of Miami RSMAS, Phone: (305)361-4884, ault(^c'.ishark.rsmas.miami.edu: Dr. JimBohnsack, NationalMarine Fisheries Service, Phone: (305)'61- 4252, i im.bohnsack,.I^tnoaa.gov^ Dr. Steven Miller, U`NCW`, (305)451-0233, [email protected].

References

Ault, J.S., Bohnsack, J.A., and Meester, G.A. 1997. Florida Keys National Marine Sanctuary: retrospective (1979-1995) assessment of reef fish and the case for protected marine areas. Pages 4t5-425 in Developing and Sustaining World Fisheries Resources: The State of Science and Management, Hancock, D.A., Smith, D.C., Grant, A., and Beumer, J.P. (eds.). 2 nd World Fisheries Congress, Brisbane, Australia, 797 p.

Ault, J.S., Bohnsack, J.A., and Meester, G.A. 1998. A retrospective (1979-1996) multispecies assessment of coral reef fish stocks in the Florida Keys. Fishery Bulletin 96(3):395-414.

Ault, J.S. and J. Luo. 1998. Coastal bays to coral reefs: systems use of scientific data visualization in reef fishery management. International Council forthe Exploration ofthe Seas ICES C.M. 1998/S:3

Ault, J.S., Meester, G.A., Luo, J., Smith, S.G., and K.C. Lindeman. 2000. Natural resources affected environment. In'Dry Tortugas National Park: Draft General Management Plan Amendment and Environmental Impact Statement'. 272 p.

16 Bohnsack, J.A. and J.S. Ault. 1996. Management strategies to conserve marine biodiversity. Oceanography 9(t):7j-82.

Bohnsack, J.A. and S.P. Bannerot. 1986.. A stationary visual census technique for quantitatively assessing community structure of coral reef fishes. NOAA Technical Report NMFS 41, 15 P.

Bohnsack, J.A. D.E. Harper, and D.B. McCellan. 1994. Fisheries trends from Monroe County, Florida. Bull. Mar. Sci. 54(3):982-1018.

Bohnsack, J.A., Ault, J.S. and 19 co-authors. 1999. Baseline data for evaluating reef fish populations in the Florida Keys. NOAA Technical Memorandum NMFS-SEFSC-427. 52 p.

Meester, G.A., J.S. Ault, and J.A. Bohnsack. 1999. Visual censussing and the extraction of average length as a biological indicator of stock health. Naturalista sicil. Vol. XXIII (Suppl.): 205- 222.

Miller. S.L., Swanson. D.W., Chiappone, M., Smith, S.G., and J.S. Ault. 2000, Rapid assessment methods for monitoring coral reef hard bottom communities: Florida Keys National Marine Sanctuary. Marine Sanctuaries Conservation Series MSD-00-X.

Schmidt, T.W., Ault, J.S. and J.A. Bohnsack. 1999. Site characterization for the Dry Tortugas region: fisheries and essential habitats. Final Report to the Florida Keys National Marine Sanctuary and the National Park Service. I I 3p. plus appendices.