30 research outputs found
Evaluating the success of the Exuma Cays Land and Sea Park, a large marine reserve in the central Bahamas
Sampling methods for Acropora corals, other benthic coral reef organisms, and marine debris in the Florida Keys: Field protocol manual for 2011-2012 assessments
The 2011-2012 sampling of Acropora corals, other coral reef benthic invertebrates, and marine debris in the Florida Keys National Marine Sanctuary (FKNMS) is being undertaken as a spatially intensive effort to provide updated population distribution and abundance information. The particular focus of surveys in the Florida Keys, as well as in the U.S. Caribbean (Puerto Rico and the U.S.V.I.), concerns the habitat distribution, colony density, size, condition, and population abundance of Acropora corals. Surveys in the Florida Keys also include assessments of urchins, mollusks, anemones, corallimorpharians, and marine debris. These additional assessments are relatively fast and easy to perform. Annual surveys for Acropora corals began in 2006 in the Florida Keys in response to their listing on the Federal Endangered Species List, as well as the paucity of large-scale information on habitat distribution, abundance, and condition in the Florida Keys. Periodic surveys for Acropora corals as part of our long-term monitoring and assessment program date back to 1999. The purpose of this field protocol manual is to outline the Acropora sampling procedures used in the Florida Keys and to standardize survey methods for the Florida and U.S. Caribbean regional population assessments planned for 2012. A previous draft of this manual was prepared for Florida Keys National Marine Sanctuary personnel in June 2011 to help guide the field sampling in 2011
Density, Spatial Distribution and Size Structure of Sea Urchins in Florida Keys Coral Reef and Hard-Bottom Habitats
The 1983-84 Caribbean-wide mortality of the long-spined sea urchin Diadema antillarum Philippi was followed by a 2nd mortality event during 1991 in the Florida Keys. Pre-mortality sea urchin densities were up to 5 ind. m-2 and the large scale decline of D. antillarum is considered to be 1 factor affecting community dynamics of Florida Keys reefs. During 1999-2000, we surveyed 125 sites using a stratified random sampling design in shallow-water coral reef and hard-bottom habitats. Strip transects were sampled to assess density, habitat utilization and size structure patterns among habitat types, regional sectors and between fished and protected areas. Nearly 17 yr after the mass mortality, D. antillarum has not recovered to pre-1983 levels, with current densities no greater than 0.05 ind. m-2, and small test sizes (1 to 2 cm) dominate. Other sea urchins such as Eucidaris tribuloides (Lamarck) and Echinometra viridis Agassiz show density and habitat distribution patterns similar to historical observations
Multiple Spatial Scale Assessment of Coral Reef and Hard-Bottom Community Structure in the Florida Keys National Marine Sanctuary
The zoning plan for the Florida Keys National Marine Sanctuary (FKNMS) established 23 relatively small no-fishing zones distributed mostly along the offshore reef tract in 1997. In 1999, a two-stage, stratified random sampling design based on the proportion of coral reef and hard-bottom types within the FKNMS was conducted. Our study focused on differences in coverage, density, and condition of benthic organisms with respect to habitat type, regional variations, and differences between no-fishing zones and reference sites at 80 locations spanning 200 km. Most variables exhibited significant spatial differences by habitat type or between individual no-fishing zones and reference sites (e.g. species richness, coral density, gorgonian density, and recruitment), although some regional differences were also apparent. Many of the differences among the no-fishing zones and reference sites reflect the placement of the zones in well-developed offshore reefs, and for many of the variables targeted, individual zones are as different from one another as from reference sites. These results emphasize the need to address spatial variations at multiple scales, and to consider a range of variables beyond common metrics such as coral cover
Historical Reconstruction of Population Density of the Echinoid Diadema antillarum on Florida Keys Shallow Bank-Barrier Reefs
The 1983–1984 caribbean-wide mass mortality of the once ubiquitous long-spined sea urchin Diadema antillarum Philippi, 1845, is one of several factors considered responsible for coral reef change throughout the region. Unfortunately, there is a paucity of pre-mortality event density data for D. antillarum in the Florida Keys, making it difficult to determine pre-1983 population density levels. results from surveys conducted during 1970–1973 in the lower Florida Keys, in shallow (\u3c12 m) fore reef habitats, yielded relatively abundant and widespread D. antillarum densities in qualitative transects at five reefs prior to the 1983–1984 die-off. In quantitative surveys at one reef, Middle sambo reef in 1972, up to 7.9 individuals m–2 were recorded using quadrats in high-relief spur and groove habitat. A second mortality event in the Florida Keys, beginning in April 1991, again depressed urchin densities that had begun to recover from the 1983–1984 mass mortality. By 1992, D. antillarum densities (\u3c0.01 m–2) were two orders of magnitude lower than pre-die-off estimates (range of 0.07–0.57 m–2 from several spur and groove reefs in the lower Florida Keys) and remained so through 2009. The pre-mortality echinoid density estimates detailed in the Florida Keys provide a baseline to compare with their current population status and should help inform managers about realistic recovery or restoration targets for D. antillarum
The Octocoral Fishery in the Southeastern U.S. and Gulf of Mexico
Octocorals, also known as gorgonians and soft corals, were previously managed by the U.S. South Atlantic (SAFMC) and Gulf of Mexico (GMFMC) Fishery Management Councils through a joint Coral Fishery Management Plan (FMP). Because octocorals are mostly collected from Florida waters, the Florida Fish and Wildlife Conservation Commission (FWC) is currently tasked with managing octocoral collection, including the monitoring of colony landings, in the Economic Exclusive Zone (EEZ) adjacent to Florida. Collection of 70,000 colonies per year total, which applies to both state and EEZ waters off Florida, is permitted under Rule 68B- 42.006 of the Florida Administrative Code, but has never been exceeded according to available landings data. Before octocoral management responsibility was transferred to the State of Florida, the SAFMC was concerned that octocoral landings data, as opposed to population data, were being used to set Acceptable Biological Catch limits and Overfishing limits under the new Federal fishery management standards. An additional concern with the octocoral fishery and other organisms captured for the marine aquarium and ornamental fisheries is that large taxonomic groups are lumped together, including species with potentially different life histories and ecological functions. This study assessed some of the characteristics of the octocoral fishery by evaluating FWC Trip Ticket data, conducting interviews with octocoral collectors, and analyzing octocoral life history information and available fishery-independent data on population densities and sizes. Based on interviews with collectors, a synthesis of trip ticket results, and population abundance estimates, the long-term stability of the octocoral fishery is not likely to change significantly. The social dynamics of the aquarium industry to seek colorful, rare, and exotic marine species for home aquaria places octocorals at the lower end of the list of desired species. Octocoral distribution and abundance information obtained from an extensive search of the literature, along with available age, growth, and habitat data, suggests that current information is comprehensive and definitive, such that stock assessment or population dynamic modeling could be considered but are probably not required to assess the status of collected octocoral species. For multiple sampling periods, over a decadal period (1999-09) in the Florida Keys, where most octocoral collection occurs, abundance estimates presented for 15 species illustrate that population sizes are large (tens of millions to hundreds of millions of colonies, per species) and abundance is stable or increasing. For example, the numbers of colonies collected in the Florida Keys in two of the collector categories represented \u3c 0.004% of the estimated population sizes. The collectors and aquarium hobbyists interviewed stated that they would welcome and use a field guide to help with octocoral identification, which would ultimately provide better fishery-dependent taxonomic resolution for collected species. The collection of octocorals below the State of Florida quota of 70,000 colonies per year threshold, which has yet to be reached according to landings data, likely does not adversely affect the octocoral populations targeted. This conclusion is based upon the large population estimates determined for octocorals relative to the small number of colonies collected. This conclusion assumes that the distribution and population sizes of targeted species will continue to be relatively stable or increase. Information collected by the State of Florida through trip tickets is probably adequate to understand and manage the octocoral fishery. Minor reporting clarifications and better taxonomic resolution in reporting would help improve the accuracy of collecting data, but improved accuracy is not required to assess the current state of the fishery-the octocoral fishery is sustainable and would likely remain sustainable at colony collection levels orders of magnitude larger
Population Status of Acropora Corals in the Florida Keys
Population declines of staghorn coral (Acropora cervicornis) and elkhorn coral (A. palmata) are often-cited examples of Caribbean reef change since the 1970s, due, in part, to disease and localized effects from storms and predation. Both corals were listed as threatened on the U.S. Endangered Species List based upon range-wide decline and poor recovery. A spatially intensive survey undertaken in the Florida Keys of Acropora corals quantified habitat distribution, colony abundance, size, and condition at 235 sites spanning over 200 km in 2007. A two-stage stratified sampling design using belt transects incorporated cross-shelf habitats and no-fishing management zones from \u3c 1 m to 15 m depth. A. cervicornis was widely distributed among sites and habitats and was particularly abundant on patch reefs, with up to 1.22 colonies/m2 and surface area coverage of 2%. A. palmata was abundant on shallow spur and groove reefs, with up to 1.25 colonies/m2 and surface area coverage of 25%. Although the prevalence of disease is relatively low, both species continue to suffer predation, as well as physical impacts from lost fishing gear. Predicting the future of these corals in Florida requires information about both their present-day ecology and geologic history in Florida
Florida Keys Population Abundance Estimates for Nine Coral Species Proposed for Listing Under the U.S. Endangered Species Act
This report presents abundance and size-class distribution estimates for nine coral species in the Florida Keys and Dry Tortugas, all of which are proposed for listing or reclassification under the U.S. Endangered Species Act (ESA). The lack of population data for these species was highlighted as a deficiency in the ESA Review Process by the Biological Review Team (BRT) in their Status Review (Brainard et al. 2011) and also by the National Oceanic and Atmospheric Administration (NOAA) (Federal Register 2012). Field sampling protocols were adapted from Aronson et al. (1994) and the Atlantic and Gulf Rapid Reef Assessment program (Kramer and Lang 2003) to measure population-level metrics of scleractinian corals, with population data analyses following Smith et al. (2011). The data in this report are based on focused surveys for Acropora corals in the Florida Keys during 2005, 2007, and 2012; and for all scleractinian coral species during 2005, 2009, and 2012; and for all coral species in the Dry Tortugas for 2006 and 2008. Colony density within belt transects and size measurements were obtained for each species present. Statistical estimation procedures for population abundance metrics – means (e.g. coral density) and totals (e.g. coral abundance) – for a two-stage stratified random sampling design were adapted from Cochran (1977), and computations were carried out using SAS statistical software. Domain-wide estimates are presented in this report
Stony Coral Species Diversity and Cover in the Florida Keys Using Design-Based Sampling
Large-scale sampling of stony coral species richness, species distribution, and cover was undertaken at 423 Florida Keys sites between Miami and SW of Key West during 2005 and 2007. A two-stage, stratified random sampling design employed belt transects to enumerate numbers of species and point-intercept surveys to quantify cover. The sampling design incorporated ten reef and hard-bottom habitats from \u3c 1 m to 27 m depth, as well as oceanographic regions and areas inside and outside of protected management zones. These data provide insights into the spatial extent and factors influencing stony coral biodiversity. For stony corals, a pool of ~50 taxa encompassing the Orders Milleporina and Scleractinia, including species and morphotypes, was recorded. Significant differences were found in species richness and cover among cross-shelf habitats, with great values on inner shelf margin patch reefs, followed by deeper fore-reef slope habitats that extended to the 27 m depth limit sampled. In contrast, the shallow fore-reef, especially in areas historically dominated by the branching coral Acropora palmata, yielded relatively low numbers of species and cover that are presently dominated by smaller, brooding corals such as Porites astreoides and Favia fragum