In 2005 and 2010, high sea surface temperatures caused widespread coral bleaching on Jamaica’s north coast reefs. Three shallow (9m) reef sites were surveyed during each event to quantify the prevalence and intensity of coral bleaching. In October 2005, 29-57% of the colonies surveyed were bleached. By April 2006, 10% of the corals remained pale/partially bleached. Similarly, in October 2010, 23-51% of corals surveyed at the same sites were bleached. By April 2011, 12% of the colonies remained pale/partially bleached. Follow-up surveys revealed low coral mortality following both events, with an overall mean of 4% partial colony mortality across all species and sites observed in April 2006, and 2% in April 2011. Mixed effects models were used to quantify the relationship between colony size and (a) bleaching intensity, and (b) bleaching related mortality among coral species. The bleaching intensity model explained 51% of the variance in the bleaching response observed during the two events. Of this 51%, fixed effects accounted for ~26% of the variance, 17% of which was attributed to species-specific susceptibility to bleaching , 5% to colony size, <1% colony morphology and 4% to the difference in bleaching intensity between the two events. The random factor (site) accounted for the remaining ~25% of the variance. The mortality model explained 16% of the variance in post bleaching mortality with fixed effects, including colony size, morphology and species explaining ~11% of the variance, and the random effect (site) explaining 5%. On average, there was a twofold difference in bleaching intensity between the smallest and the largest size classes. Modelling the relationship between colony level characteristics and site-specific environmental factors on coral species’ susceptibility to thermal stress can shed light on community level responses to future disturbances.

Samples of Porites porites rubble were collected from across three fringing reefs which lie along a eutrophication gradient in Barbados, West Indies. The coral skeleton fragments were examined for clionid sponges. Data collected from the reef crest and fore reef zones and from across the range of distances and depths were pooled for each reef to compare indices of sponge abundance along the eutrophication gradient. Significant differences between the reefs were found for the proportion of rubble invaded (ANCOVA, p = 0.004), number of invasions per sample (ANCOVA, p = 0.002), and number of species per sample (ANCOVA, p = 0.018) but not for total surface area of sponge invasions per sample (ANCOVA, p = 0.064). All the indices demonstrated an increase with increasing eutrophication level. Clionids were found in nearly twice as many of the pieces collected from the most eutrophic site (41%) as from the least eutrophic (24%). Since clionids may be the principal bioeroders of coral reefs, an increase in their abundance due to excessive pollution likely results in greater bioerosion of affected reefs. The mean abundance of Type 3 corals was found to be positively related to the frequency of boring sponge invasion, suggesting that increased bioeroision may be partly responsible for community shifts toward Type 3 corals in polluted waters. One new variety and three new species of boring sponges of the genus Cliona were found. A new variety of C. amplicavata Rutzler is described, Cliona species 2 of MacGeachy is redescribed and Cliona species 4 and Cliona species 5 are described for the first time. Cliona species 5 may become an important bioeroder in Barbados and other Caribbean islands since it flourishes under high eutrophic conditions which are beginning to plague West Indian reefs. (Abstract shortened by UMI.)

No description available.

Multivariate ordination techniques were used to characterize the direction and magnitude of coral community changes on west coast reefs in Barbados between 1982 and 1992, and to relate these changes to coastal eutrophication and variation in Diadema antillarum densities (grazing pressure). D. antillarum densities were substantially lower in 1992 than in 1982, reflecting the 1983 mass mortality event. Reductions in urchin density were greater on less eutrophic reefs than eutrophic reefs. Cover by macrophytic algae increased, cover by crustose coralline algae decreased, and the number of coral species decreased between 1982 and 1992. With the notable exception of the most eutrophic reef, coral cover decreased over the 10 year period. Changes in algal cover across reefs between 1982 and 1992 were strongly correlated with decreases in D. antillarum densities, and were therefore typically greater on less eutrophic reefs, indicating that reduced grazing pressure has more strongly influenced algal cover changes than prevailing eutrophication levels. Coral species composition changed at all sites between 1982 and 1992, and except at the most eutrophic site, the direction of change was directly related to reduced D. antillarum densities and associated algal cover changes. Temporal change at the most eutrophic site was best explained by the prevailing high level of eutrophication, and resulted primarily from a substantial increase in the cover of one species, Porites porites. The decrease in coral cover that occurred on most of the study reefs in the face of the increasing cover by macrophytic algae was typically accompanied by an increase in the relative abundance of Type 1 (high recruitment, high natural juvenile mortality) to Type 2 (low recruitment, low natural juvenile mortality) corals.

Understanding recent decades of coral community change has been hindered by a shortage of long-term monitoring and a lack of tools that provide a lasting record of benthic reef communities. To increase our understanding of Caribbean coral reef dynamics, this dissertation research developed and used innovative technologies involving landscape mosaic images and 3D reef models, to analyze a novel 40 year dataset of coral community health from Andros Island, Bahamas. Historical data from Andros Island (1968-2000) were provided as part of a Cooperative Research and Development Agreement (CRADA) between the University of Miami and the Naval Undersea Warfare Center Division Newport. Long-term monitoring at Andros Island revealed that reef decline was a-typical over recent decades. Coral mortality and disease increased significantly between 1970 and 2000, whereas macroalgal cover did not. To complement studies of coral mortality and disease, the resilience and resistance of individual coral species at Andros were measured from 1972 to 2008. Of the 24 species studied, only three (Siderastrea siderea, Montastraea cavernosa, and Porites astreoides) were resistant to recent disturbance histories, whereas Porites porites was resilient. Further studies using 3D models explored relationships between coral population dynamics and spatial patterns of coral species. Results indicated that the arrangement of dominant coral species and the processes of recruitment, growth, and mortality were non-random over time. In summary, the application of mosaic images and 3D reef models to a previously un-published long-term coral health dataset led to improved understanding of factors controlling past reef communities.

Marine reserves are promising tools for fisheries management, and are especially suited for complex, multi-species fisheries. Recent work has focused on the design of reserves to achieve particular management objectives and on defining appropriate indicators for monitoring to determine whether these objectives are being met. In principle, there should be a strong correlation between biological, social and economic indicators that are all correlated with fish abundance and ecosystem health. In practice, different indicators are often inconsistent, and it is common for researchers and fishers to have conflicting opinions on how well reserves are meeting management goals. I suggest that these discrepancies are not necessarily due to conflicting opinions regarding management objectives, but rather that the inherent biases in different sampling schemes may cause different measures of the same parameter to be uncorrelated. For example, scientists tend to sample only snapshots in time and space in randomly chosen locations, while fishers sample over much greater temporal and spatial scales but in non-random locations. Furthermore, marine ecosystems are extremely complex, and failing to account for the full extent of this complexity may lead to erroneous measurement of biological trends. The purpose of this dissertation is to determine the causes of discrepancies between different types of indicators using a multidisciplinary approach. A detailed study of the Glover’s Reef Marine Reserve (GRMR) in Belize provides a basis for comparison. Chapters 2 to 4 of the dissertation focus on understanding how the GRMR has functioned to produce fisheries benefits, and elucidating some of the factors responsible for variation in species’ responses to reserve protection. Chapters 5 to 7 of the dissertation focus on comparisons of different indicators of changes in fish abundances, and explain the circumstances under which indicators may disagree. With a better understanding of the functioning of the GRMR based on both scientific and local knowledge, efforts can be made to develop more appropriate indicators, and these indicators can then be tested for use in other coral reef reserves worldwide.

The reef corals Pocillopora damicornis and Montipora verrucosa were cultured under various controlled temperatures and light conditions at Ulupau Head Microcosm facility. The skeletal carbonate deposited under different experimental regimes was analyzed for 13C and 18O. Coral skeletal 013C values varied with light dose and correlated with changes in zooxanthellar pigment. The o13C value of skeletal aragonite seems to be controlled by oxidation of photosynthetically produced organic matter. Functionally significant relationships between coral skeletal o18O values and temperature have been determined. The temperature coefficients of the o18O values (-4.20) are the same as the first order coefficient in the equilibrium paleotemperature equation, but the o18O values have species-specific offsets from equilibrium. These offsets may be attributed to the activity of the coral's zooxanthellae. Based upon the results of this study a model of coral skeletal isotopic incorporation is presented. / Typescript. Thesis (M. S.)--University of Hawaii at Manoa, 1979. Bibliography: leaves 94-102.

Twenty-seven species of known or suspected coral skeletal borers were identified from shallow Hawaiian reefs. In comnarison to inventories of the borer communities collected from other tropical areas Hawaiian corals had an abundance of polychaetous annelids, fewer species of sipunculans,and acrothoracican barnacles, and far fewer boring sponges. Polychaetes were responsible for the majority of the bioerosion of dead coral in Kaneohe Bay, Oahu. Comparisons of living and dead sections of coral colonies indicated that the borer community was more diverse and abundant in areas of the skeletons lacking living tissue. Skeletal densities of three common coral species with branching growth form were found to influence the abundance of coral borers. The least dense skeletons had greater population densities of borers. It is suggested that these three species of corals can coexist in close proximity due, in part, to the development of varying abilities to withstand invasion by skeletal borers. In order to determine rates, si te preference and seasona.li.ty of settlement a series of settlement plates were cut from coral and placed in the field at ten sites in Kaneohe Bay, Oahu. Extrapolating from the surface area of the settlement plates, mean recruitment rates of coral borers were found to be 10,000 - 50,000 individuals m-2 month-1. The recruitment rates and species composition of epibiotic and borer faunas settling; on the dead coral plates differed dramatically between areas in Kaneohe Bay due to the effects of differences in physical and biological factors caused by sewage and slltation. The larvae of coral borers generally lacked clear seasonal settlement periods, suggesting that one or more mechanisms (e.g. continuous reproduction, long pelagic phase, etc.) functioned to assure the presence of larvae throughout the year. The ultimate cause for the development of such a strategy may be that the time and location of the production of suitable settlement sites on the reef surface is. unpredictable. Some of the larvae of both epibiotic and borer species exhibited settlement selectivity with respect to the position of the settlement surface. This finding indicates that the distribution of borers in coral skeletons might be due, in part, to active selection by the laryae for particular conditions. Development of the epibiotic and borer communities of dead coral was monitored using sequentially collected blocks cut from the coral Porites lobata. The abundance and species composition of these communities were found to differ between sites in Kaneohe Bay because of several biological and physical factors. In the south bay increased food supplies (in the form of plankton and plankton-derived detrital material). due to sewage enrichment, support extensive populations of filter and deposit-feeding invertebrates including coral borers. Sewage diversion did not appear to have had any dramatic effect on these communities by the end of the study period. In the north bay, where food availability is lower, fewer borers and epibiotic organisms were collected. The effects of fish grazing are considered to be another important factor determining the species composition and abundance of the coral borer community. Grazing fish were rare in south Kaneohe Bay during the study period, which may help to explain the abundance of sessile epifaunal species. In the north bay fish grazing is extensive and contributes to the growth of encrusting coralline algae on the test blocks and the benthos. Based on the results of the long term block study it was found that in Hawaii sessile filter-feeding invertebrates do not exclude coral borers from the substratum or inhibit their growth. In south Kaneohe Bay, where conditions caused increased abundances and growth rates of filter and depositfeeding invertebrates, bioerosion rates were accelerated. Encrusting coralline algae, which flourish on reefs exposed to fish grazing (eg. north Kaneohe Bay), inhibit settlement of borers and grow over burrow apertures, thus reducing the population of borers within the dead coral. Bioerosion rates of exposed, coralline algal covered, dead coral substrata are very low on pristine shallow Hawaiian reefs. / Bibliography: leaves 181-192.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 91-96). / vi, 149 leaves, bound ill., map 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 72-76). / vii, 99 leaves, bound ill. (some col.), maps (some col.) 29 cm