Thesis (Ph.D.)--University of Rhode Island, 2007. / Includes bibliographical references (leaves 295-311).

Coral reef declines, particularly in coastal zones, have been linked to thermal stress and anthropogenic impacts on water quality. St. Lucie Reef near Stuart, Florida receives increased estuarine efflux as a result of watershed changes and management policies that have substantially altered historic, natural flows. This research used ambient and elevated temperatures (25°C and 30°C, respectively), and offshore versus St. Lucie Estuarine discharge water to investigate the individual and interactive effects of thermal and water quality stress on Montastraea cavernosa, a dominant scleractinian coral species at St. Lucie Reef. These goals were accomplished using ex-situ, factorial, experimental design that was supplemented with existing in-situ monitoring on St. Lucie Reef. Zooxanthellae density and chlorophyll content were evaluated to determine effects on the corals and their symbionts. Zooxanthellae populations were significantly affected by thermal stress. Significant interactions between temperature and water treatment were observed, suggesting that the impacts of discharge water may be supplanted when corals are exposed to thermal stress. In a supplement to the experiment, M. cavernosa colonies transplanted from Palm Beach to St. Lucie Reef demonstrated resilience despite exposure to more variable environmental conditions. Collaborative partnerships with multiple state agencies and local government offices facilitated data sharing to inform decision making for South Florida’s resource management strategies. Creating effective resource management is crucial for the conservation of coastal ecosystems impacted by land-based sources of pollution both locally and globally. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Global warming from anthropogenic greenhouse gas emissions causes temperature increases in aquatic ecosystems. The rise in environmental temperatures places sensitive organisms under thermal stress. Reef-building corals are a critically important group of animals that provide many ecosystem services for coral reef ecology and the economy and are at a high risk of loss from thermal stress. Thermal stress causes corals to lose their colour, i.e. become bleached, resulting from the loss of symbiont zooxanthellae. This diminishes the energetic benefits that zooxanthellae provide to corals leading to a decline in coral health and high mortality rates. However, corals are also predators and can thus draw nutrients from zooplankton prey to supplement their nutritional requirements. This study investigated whether heterotrophic feeding can ameliorate the effects of thermal stress on coral physiology by providing an alternative energy source to zooxanthellar photosynthesis. Fragmented Pocillopora damicornis coral colonies were exposed to daily maximum temperatures of up to 31°C while being either starved or fed. During the experimental period coral nubbins were monitored for changes in polyp extension, oxygen consumption rate, feeding rate, colour, chlorophyll a content, zooxanthellae density, antioxidant potentials and DNA integrity during stress and after a short recovery period. It was found that, as expected, coral polyp extension, oxygen consumption rate, colour health, chlorophyll a content, zooxanthellae density and DNA integrity were all adversely affected by thermal stress. This indicted that all these measurements were viable biomarkers for assessing the negative effects of thermal stress on coral health. Coral colour, oxygen consumption rate, chlorophyll a content, lipid content, antioxidant potential and DNA integrity were all significantly improved by feeding. These results indicate that feeding does play a role in improving overall coral health and supports the physiological processes in coral tissue during and after thermal stress. The conclusions from this study also have great significance for coral reef ecology and management as predictions of reef resilience can be made from zooplankton ecology and boosting zooplankton availability to corals may be considered to mitigate the harmful effects of thermal stress and bleaching. / M.Sc. University of KwaZulu-Natal, Durban 2013.

The purpose of this paper is to evaluate the need for permanent mooring buoys at the popular off-shore islands of Pattaya, Thailand. By investigating the ecological, social and economic gains and losses of installing such buoys, the project aims to examine whether such buoys would help support a more sustainable development in the area. In order to fulfil the aims and objectives of the project, a literature study, two different questionnaires, interviews, line intercept transects (LIT) and a boat traffic survey were performed.  The results prove that every dive store operator, 71% of the dive instructors/dive masters and 65% of the tourist divers that took part in the interviews or questionnaires have observed anchor damages in the area. This is supported by the results of the LITs, which, although differing greatly between depths, reveal a top score of 44% damaged corals (of which 20% were apparent anchor damages) at snorkelling depth at site 3. At diving depth the damage indexes were generally lower, revealing a top score of 38% damaged corals at Site 2, but no definite anchor damages. The boat traffic survey showed that 192 boats were active in the area, of which 47 used an anchor, during a 3 hour period a Saturday morning. The results also prove that dive store operators and questionnaire participants generally agree that divers wish to see healthy reefs and great aquatic biodiversity when visiting a dive site. The interviews showed that all dive store operators have a positive attitude towards an installation of mooring buoys in the area, which could protect the local reefs and thereby their own business. 85% of the tourist divers that took part in the questionnaires stated they would be willing to pay extra (where a majority of those with a WTP would be willing to pay 7-13 USD) if they could be guaranteed to see healthy coral reefs and a great diversity in species and 88% stated they would be willing to pay extra (where a majority of those with a WTP would be willing to pay 0.7-1.7 USD)  to support a permanent mooring buoy system.  The interviews and the questionnaires also prove that healthy coral reefs hold a special sentimental value, providing invaluable recreational opportunities to humankind.  Conclusively the results indicate that there is a need for permanent mooring buoys in the area. The ecological, social and economic gains of installing permanent mooring buoys seem to overshadow the cost of installation and maintenance of the buoys, meaning the buoys would most certainly improve the conditions for a more sustainable development in the area.

Thesis (MTech (Oceanography))--Cape Peninsula University of Technology, 2010 / Coral reefs are in a worldwide state of crisis due to overexploitation. One of the factors contributing to the over exploitation is the marine ornamental industry. This industry utilises a diversity of organisms, comprising approximately 1470 species of fish and more than 300 species of invertebrates. Between April and December 2007, five of the 18 companies who had import permits for South Africa, imported a total of 359 different ornamental species, 252 of these were fish species while the remaining 107 species were invertebrates. During these nine months a total of 32 005 individual organisms were imported into South Africa by the five companies. There were two groups of fish that represented the highest import volumes. These were Amphiprion spp. and Pomacentradae spp., as well as the Gobidae spp. These groups represented 38% and 19% respectively of the total number of fish imported" Aquaculture has the potential to substantially reduce the harvesting pressure on coral reef organisms globally. A small-scale multi-species mariculture system was designed and constructed for benthic egg-laying species of fish (brood stock), corals, and ornamental algae. The system was designed to be low cost and easy to operate. The total capital costs for the system was R15 680.70. In order to estimate the potential yield of an aquaculture facility it is important to know the growth rate of the proposed species under pilot conditions. The use of artificial lighting regimes in aquaculture comes at a financial cost. It is for this reason that it is important to know what lighting scenario yields the highest growth rate of corals. The effects of photoperiod were tested on Sinularia sp. of coral. Two photoperiods were tested, namely: Groups (8:16 h Iight:dark cycle) and Group12 (12:12 h light:dark cycle). No significant difference in weight was found between Group8 and Group12 (p = 0.975). There was however a significant increase (p = 0.002) in Surface-area Pixel Value (SPV) for Groups (1996.73 millipixels pixel-1 day -1) compared to Group12 (983.73 millipixels pixel-1 day -1). The use of a 8:16 h lightdark cycle can thus yield coral of a larger size but not necessarily a higher mass.

[Truncated abstract] The extent to which marine populations are connected by larval dispersal is crucial to their distribution, maintenance and diversity. Thus, for the effective conservation of threatened systems such as coral reefs, understanding patterns of connectivity is essential. However, the biophysical mechanisms that retain or disperse larvae within and among populations are poorly understood. Though the open ocean environment provides the opportunity for long-distance dispersal, if this potential is only rarely realised, recruits produced from afar are unlikely to contribute to the local-scale demography of populations over ecological time frames, but will limit broad-scale genetic diversification over evolutionary time. This thesis explores the extent of genetic and demographic connectivity of two species of reef-building corals over a range of spatial scales among the discontinuous reef systems of northwest Australia. ... Putative source and sink dynamics were not random, but were associated with levels of disturbance and recovery from a recent and catastrophic coral bleaching. When S. hystrix samples from another two offshore systems were included in the analysis, large differences among systems showed that gene flow over hundreds of kilometres is rare over microevolutionary time scales that account for connections over multiple generations. Levels of subdivision over the same spatial scales were markedly lower in the acroporid coral, Acropora tenuis, than in S. hystrix. These results are congruent with expectations based on reproductive mode; in contrast to S. hystrix, which releases brooded larvae that are competent to settle immediately, A. tenuis broadcasts its gametes, and after external fertilisation, the larvae need to develop for several days before they are competent to settle. Despite the differences in levels of broad-scale subdivision, in both species significant differentiation was detected between reefs within systems (>10 km), and between sites within some reefs (< 10 km). These results indicate not only that dispersal between reefs and even some reef patches is restricted, but also that hydrodynamics influence retention of brooded and spawned larvae in similar ways. Further analysis of A. tenuis populations from two coastal systems detected significant differences in genetic diversity among the four major systems of northwest Australia. Additionally, genetic divergence between the coastal and offshore zones was greater than expected by the geographic separation of systems, indicating that connectivity between these zones via transport of A. tenuis larvae on oceanic currents occurs rarely even over microevolutionary time scales. This study has two primary implications for conservation. First, since coastal and offshore reefs of northwest Australia appear to be discrete genetic entities, they have independent evolutionary potential to adapt to local conditions and environmental change. Second, systems, reefs and some reef patches of northwest Australia are demographically independent units. Therefore, designs of coral reserve networks should consider routine dispersal distances of kilometres to a few tens of kilometres.

Coral reefs are in global decline, with seaweeds increasing as corals decrease. Though seaweeds have been shown to inhibit coral growth, recruitment, and survivorship, the mechanism of these interactions is poorly known. Here we use field experiments to show that contact with four common seaweeds induces bleaching on natural colonies of Porites rus. Controls in contact with inert, plastic mimics of seaweeds did not bleach, suggesting treatment effects resulted from allelopathy rather than shading, abrasion, or physical contact. Bioassay-guided fractionation of the hydrophobic extract from the red alga Phacelocarpus neurymenioides revealed a previously characterized antibacterial metabolite, Neurymenolide A, as the main allelopathic agent. For allelopathy of lipid soluble metabolites to be effective, the metabolites would need to be deployed on algal surfaces where they could transfer to corals on contact. We used desorption electrospray ionization mass spectrometry (DESI-MS) to visualize and quantify Neurymenolide A on the surface of P. neurymenioides and found the metabolite on all surfaces analyzed. The highest concentrations of Neurymenolide A were on basal portions of blades where the plant is most likely to contact other benthic competitors.

Marine protected areas (MPAs) have been established along the East African coast to protect coral communities from human and natural disturbance. Their success is dependent on the degree to which resource populations are self-seeding or otherwise connected. Estimates of contemporary gene flow on or between south-east African reefs are thus required to reveal the interdependence of the South African coral communities and those to the north. Accordingly, the ecologically relevant (1 or 2 generations) connectivity of two broadcast-spawning corals, Acropora austera and Platygyra daedalea, was assessed on reefs in the region, from the Chagos Archipelago to Bazaruto Island in Mozambique and Sodwana Bay in South Africa, using hyper-variable genetic markers. Analysis of genetic diversity and differentiation provided evidence for the existence of four discrete genetic populations of A. austera and five of P. daedalea in the sampled area. Higher genetic diversity was found on northern South African reefs (Nine-mile Reef and Rabbit Rock) and migration patterns inferred from assignment tests suggested that, at ecological time scales, South African reefs are disconnected from those in Mozambique and might originate from a source of gene flow that was not sampled. The analysis of fine-scale genetic connectivity conducted on Two-mile Reef (TMR) demonstrated the existence of significant spatial genetic structure at the reefal scale that might be related to the non-random dispersal of coral larvae, putatively explaining the genetic discontinuity observed in the region. Altogether, the results are consistent with the isolation observed in other studies using less variable markers, and support the hypothesis that there is demographic discontinuity between the coral populations along the south-east African coast. More importantly, Acropora austera and P. daedalea represent different life strategies in the South African reef communities yet manifested similar genetic patterns, suggesting that these corals are responding similarly to forces that are driving genetic connectivity in the region. For management purposes, the genetically distinct populations identified at each of the spatial scales analysed in this study may correspond to management units, or evolutionarily significant units. Furthermore, since some reefs appear to act as “landing-sites” for migrants (Nine-mile Reef) and there is evidence of significant within-reef genetic structure (TMR), an adaptive management framework would be the best option for the MPA in the region. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2014.

Thesis (M.Sc.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: p. 87-93.

This dissertation investigates social and ecological factors that facilitate effective management of coral reefs as social-ecological systems. Meta-analytical and field-based methods were employed to examine current management challenges and identify strategies that improve management effectiveness and coral reef health. A meta-analysis was used to evaluate biological indicators of reef health in relation to the types of fishing regulations in place (no-take areas, gear restriction areas, and periodic closures) and the actor groups (community-based, co-management, state, private) involved in management efforts for coral reef fisheries throughout the world. Other than enhancement of fish biomass within no-take areas that was significantly greater than in gear restriction areas, most biological indicators benefitted similarly from management techniques of no-take areas and gear restriction areas. Community-based and co-management were the best performing management arrangements for some biological outcomes but require further case studies to verify findings. Investigation of management effects by region indicated that previously degraded reefs received fewer benefits from management implementation than did relatively healthier reefs. For field investigations, the Comoros islands in the Western Indian Ocean served as a model for tropical coral reefs with challenging socioeconomic contexts, high biodiversity, and high vulnerability to coral reef degradation. Empirical study at 21 sites was used to identify the relative effects of natural and anthropogenic threats to coral reefs of the Comoros. Most previous studies of reef health focus on primarily natural factors or a single anthropogenic threat. This study examined suites of natural factors and human activities to identify the relative importance of each on reef health. Human activities including fishing, sand extraction, and beachfront housing and development were the best predictors of reef health status. Most notably, human population and fishing predicted fish richness, abundance, and biomass with seasonal variation in the effects, while site orientation strongly predicted benthic cover. Field studies in the Comoros were also used to investigate the roles of community and state actors in co-management and compare effectiveness of comanagement across sites with varying levels of actor participation. Effective management was found to occur with community or `meta-community' (in this case, a Marine Protected Area in which the efforts of several communities were organized) participation in governance and support of state or external agents, while resilient management that overcame considerable challenges was found to occur only with strong community participation and leadership in governance. External agents were found to contribute to development of meta-community governance structure and initiation of community participation through education and capacity building. The findings from these studies reveal that coral reef management can be improved through context appropriate regulations that address detrimental human activities and through wide acceptance and participation in governance with cooperation among states, communities, and external agents.