Coral reefs persist in an accretion-erosion balance and ocean acidification resulting from anthropogenic CO2 emissions threatens to shift this balance in favor of net reef erosion. Corals and calcifying algae, largely responsible for reef accretion, are vulnerable to environmental changes associated with ocean acidification, but the direct effects of lower pH on reef erosion has received less attention, particularly in the context of known drivers of bioerosion and natural variability. This study examines the balance between reef accretion and erosion along a well-characterized natural environmental gradient in Kāne‘ohe Bay, Hawai‘i using experimental blocks of coral skeleton. Comparing before and after micro-computed tomography (µCT) scans to quantify net accretion and erosion, we show that, at the small spatial scale of this study (tens of meters), pH was a better predictor of the accretion-erosion balance than environmental drivers suggested by prior studies, including resource availability, temperature, distance from shore, or depth. In addition, this study highlights the fine-scale variation of pH in coastal systems and the importance of microhabitat variation for reef accretion and erosion processes. We demonstrate significant changes in both the mean and variance of pH on the order of meters, providing a local perspective on global increases in pCO2. Our findings suggest that increases in reef erosion, combined with expected decreases in calcification, will accelerate the shift of coral reefs to an erosion-dominated system in a high-CO2 world. This shift will make reefs increasingly susceptible to storm damage and sea-level rise, threatening the maintenance of the ecosystem services that coral reefs provide.
Expectations about ecosystem based management (EBM) differ due to diverging perspectives about what EBM should be and how it should work. While EBM by its nature requires trade-offs to be made between ecological, economic and social sustainability criteria, the diversity of cross-sectoral perspectives, values, stakes, and the specificity of each individual situation determine the outcome of these trade-offs. The authors strive to raise awareness of the importance of interaction between three stakeholder groups (decision makers, scientists, and other actors) and argue that choosing appropriate degrees of interaction between them in a transparent way can make EBM more effective in terms of the three effectiveness criteria salience, legitimacy, and credibility. This article therefore presents an interaction triangle in which three crucial dimensions of stakeholder interactions are discussed: (A) between decision makers and scientists, who engage in framing to foster salience of scientific input to decision making, (B) between decision makers and other actors, to shape participation processes to foster legitimacy of EBM processes, and (C) between scientists and other actors, who collaborate to foster credibility of knowledge production. Due to the complexity of EBM, there is not one optimal interaction approach; rather, finding the optimal degrees of interaction for each dimension depends on the context in which EBM is implemented, i.e. the EBM objectives, the EBM initiator’s willingness for transparency and interaction, and other context-specific factors, such as resources, trust, and state of knowledge.
In 2011 humans caught and consumed 78.9 million tonnes of fish, crustaceans, molluscs and other species groups from the world’s oceans, accounting for 16.6% of the world’s animal protein intake (FAO 2012). This is projected to increase further, to over 93 million tonnes by 2030 (World Bank 2013). Global demand for fish products has increased dramatically over recent decades. Fishing is also an important livelihood, globally providing employment to 38.4 million people of whom 90% are employed in small-scale fisheries (FAO 2012). The importance of fisheries continues to rise as coastal populations are increasing, and rapidly growing economies are driving up demand for fish. While aquaculture is increasing to meet some of this demand, wild capture fisheries continue to be critically important.
This review of the scientific literature provides a deep exploration of the importance of mangroves for wild capture fisheries. While mangroves are widely recognized for their role in enhancing both small scale and commercial fisheries, they are rapidly disappearing. A fuller understanding of this ecosystem service and its value in both social and economic terms will help enhance the sustainable management of both mangroves and fisheries.
The report firstly discusses some of the ecological processes which underpin the key role of mangroves in fisheries enhancement, followed by an exploration of the different mangrove- associated fishery types. As the fisheries value of mangroves is highly site specific, the report explores the drivers and mechanisms which can help to explain for different locations how many fish a mangrove produces, how many are caught by humans, and what the fisheries value is, both in economic terms, as a food supply or through the livelihoods that they support. Decision-makers can use this information to determine where fish productivity is highest, which allows them to make adequate decisions relating to conservation and restoration actions and sustainable fishing. We conclude with management recommendations for maintaining or enhancing the value of mangroves for fisheries for the long-term.
The role of mangroves in protecting our coasts against natural hazards such as storms, tsunamis and coastal erosion has been widely promoted. But the supposed coastal protection services of mangroves have also been subject to debate. The Nature Conservancy and Wetlands International together with the University of Cambridge set out to map the current state of knowledge about the role of mangroves in coastal defence and put the different findings and views in perspective. The conclusion is that mangroves can indeed reduce the risk from a large number of hazards. This practical guidebook summarises the findings of the reviews and provides practical management recommendations to coastal zone managers and policymakers. These are the key messages:
Section 1. Is my shore at risk?
Section 2. The role of mangroves in coastal risk reduction
Section 3. Managing mangroves for coastal defence
Section 4. Recognizing the multiple values of mangroves
Despite many biotic, physical, and political challenges for place-based conservation in open ocean environments, conservation of discrete oceanic regions by designating pelagic marine protected areas (PMPAs) has gained considerable traction. In the oligotrophic central Pacific, a patchy and dynamic ecosystem, a robust network of PMPAs has recently been established. However, evaluations of PMPA efficacy in providing appropriate habitat coverage for pelagic species are lacking, particularly in the tropics. Here, we used high resolution GPS tracking and home range analyses of tropical boobies to determine the distribution and foraging habitat use of three sympatric species (Sula sula,Suladactylatra, and Sulaleucogaster) in two PMPAs that varied substantially in size and shape. At each site we characterized the extent and use of foraging habitat inside and outside the PMPA that surrounded each breeding colony. We found profound variation within and among species in foraging behavior and habitat use across the two sites; this was partially explained by variation in bathymetry. Yet, despite variation both in PMPA size and shape, and in foraging behavior of the birds, we determined that the PMPAs each encapsulated more than 85% (n = 216 trips) of foraging habitat for each species, indicating that these PMPAs provided important habitat coverage for highly mobile tropical species. While this study highlights the challenges in effectively designing PMPAs even for relatively well-studied, central place foragers, given strong variation in foraging ecologies across sites, it also suggests that PMPAs do provide meaningful habitat coverage for at least some pelagic species.
Giant clams (Hippopus and Tridacna species) are thought to play various ecological roles in coral reef ecosystems, but most of these have not previously been quantified. Using data from the literature and our own studies we elucidate the ecological functions of giant clams. We show how their tissues are food for a wide array of predators and scavengers, while their discharges of live zooxanthellae, faeces, and gametes are eaten by opportunistic feeders. The shells of giant clams provide substrate for colonization by epibionts, while commensal and ectoparasitic organisms live within their mantle cavities. Giant clams increase the topographic heterogeneity of the reef, act as reservoirs of zooxanthellae (Symbiodinium spp.), and also potentially counteract eutrophication via water filtering. Finally, dense populations of giant clams produce large quantities of calcium carbonate shell material that are eventually incorporated into the reef framework. Unfortunately, giant clams are under great pressure from overfishing and extirpations are likely to be detrimental to coral reefs. A greater understanding of the numerous contributions giant clams provide will reinforce the case for their conservation.
We argue that stakeholder commitment and cooperation is essential for the success of strategic coastal and marine management initiatives and draw upon social identity theory to explain how inter-group relationships can either support or hinder cooperation across stakeholder groups. We analyse data from interviews carried out with 24 coastal and marine stakeholders from the Northern Territory, Australia, looking at how stakeholders describe their objectives for coastal and marine management and evidence of social identity effects either facilitating or impeding cooperation between stakeholders. While most participants sought improvements to coastal and marine management, only some were thinking in terms of a more regional-scale, forward-looking and integrated approach. Strong social identity effects inhibiting cooperation between stakeholders were evident in many of the interviews. However, the interviews also revealed shared objectives (e.g., the need for more data, to avoid duplication of effort, and more transparent and systematic decision-making) that could serve as a basis for developing a common social identity, and fostering the commitment and cooperation needed for strategic coastal and marine management initiatives.
This paper illustrates an index-based coastal risk assessment that was performed on a micro-tidal alluvial plain taking into account the relative sea level rise (RSLR) for the evaluation of coastal vulnerability and exposure. This process took into account both the inundation of inshore land and the beach retreat due to storm surge, calculated on the basis of geomorphological data (bathymetry, sedimentology and beach width) and wave climate. The evaluation process was conceived with reference to a low and high hazard, associated with a wave storm with 1 year and 50 years return period. For the latter case, the response to RSLR was calculated taking into account both isostatic response and ice cap melting due to global warming, while the vertical land movement was assessed taking into account the different its rates in the northern and southern coastal area. The exposure and the damage of the coastal assets were evaluated with a simplified conceptual framework, which uses land cover data and a statistical population dataset.
The risk assessment procedure was applied to Sele coastal plain, which involves numerous properties and important infrastructures, and is strongly susceptible to marine inundations. A sensitivity analysis of the vulnerability and the risk relative to different hazards and to RSLR was performed. Moreover, the final risk assessment classification was validated with a conceptual framework based on the observed damage ranking related to the tested coastal area.
The obtained results showed that the northern high density urban areas were characterized by the highest risk, followed by some central areas with strong localized erosive focus. On the contrary, the southern zones, with wider beaches and almost intact dunes, were characterized by the lowest risk level. The results of this study were used for the development of a coastal protection project which, in fact, provided a different scheme for the coastline northwards and southwards of the Sele river mouth, according to the different risk ranking established.
Managed retreat is rarely implemented on exposed sandy coasts because of public interest in beach recreation and the great human-use value of existing beaches and dunes. The feasibility of retreat on the sandy coast of the Adriatic Sea in the Region of Emilia-Romagna was evaluated at a site with a single user facility (a beach concession) backed by public parkland. A conceptual scenario of changes to landforms and habitats was developed for the retreat option. Interviews with key stakeholders revealed perceptions of alternatives for addressing erosion and flooding by managed retreat or by protecting existing features in place.
The beach concession occupies a segment of shore between an eroding (−9.3 m yr−1) washover barrier updrift and an accreting beach downdrift. Landward of the concession is a portion of the Po Delta Park, consisting of a brackish lagoon and marsh and an artificially-created freshwater lake. Shore protection projects have maintained the concession and the integrity of a dike protecting the lake. Allowing retreat to occur would cause (1) loss of the concession in its present location; (2) erosion of the dike, converting the lake to brackish habitat; and (3) migration of the shoreline to a pine forest, campground and residences that are now 500 m from the shoreline. Freshwater and pine forest habitat would be lost, but salt water wetland and pioneer coastal species would be restored. The beach and campground could still be used as the shoreline migrates inland, but with less fixed infrastructure. Landward facilities could be protected by a ring dike.
At issue is whether normally dynamic and short-term landforms and habitats should be protected as static features in perpetuity and whether human actions should be taken to protect human-created nature (lake, pine forest) against natural evolutionary processes. Stakeholders indicated that managed retreat should occur eventually but existing features should be protected now. The retreat option is compatible with Regional ICZM plans, but differs from the standard engineering designs actually suggested for implementation. The benefits of managed retreat on exposed sandy shores can only be presented in conceptual terms until demonstration projects provide concrete answers, so it is not surprising that the undocumented benefits of a more dynamic shoreline have little appeal relative to maintaining the status quo.
Similar to many coastal or island countries, the waters around St. Kitts and Nevis, an island nation in the Eastern Caribbean, are home to multiple, cumulative, and often conflicting uses of the sea. Marine spatial planning and marine zoning hold great promises for addressing and balancing a number of marine management objectives in St. Kitts and Nevis under a common framework. We outline the key activities that led to the development of a draft marine zoning design for St. Kitts and Nevis, and discuss outcomes of the planning process and possible next steps towards implementation of a marine zoning plan. The key activities were focused around: 1) engaging stakeholders; 2) establishing clear objectives; 3) building an information base that spatially represents marine uses (i.e., a multi-objective geodatabase); 4) generating tools to assist stakeholders and decision makers in generating a zoning design and considering options and tradeoffs (i.e., decision support products); and 5) outlining the location of zones via a participatory process. The vision and foundation for marine zoning we outline here can continue to be leveraged by the citizen of St. Kitts and Nevis and serve as a model in other places engaged in similar efforts.
A significant barrier to the use of public participation GIS (PPGIS) and crowd-sourcing for conservation planning is uncertainty about the quality of the spatial data generated. This study examines the quality of PPGIS data for use in conservation planning. We evaluate two dimensions of spatial data quality, positional accuracy and data completeness using empirical PPGIS data from a statewide study of public lands in Victoria, Australia. Using an expert-derived spatial conservation model for Victoria as a benchmark, we quantify the performance of a crowd-sourced public in their capacity to accurately and comprehensively identify areas of high conservation importance in the PPGIS process. About 70% of PPGIS points that identified biological/conservation values were spatially coincident (position accurate) with modeled areas of high conservation importance, with greater accuracy associated with locations in existing protected areas. PPGIS data had less positional accuracy when participants identified biological values in urban areas and on non-public lands in general. The PPGIS process did not comprehensively identify all the largest, contiguous areas of high conservation importance in the state, missing about 20% of areas, primarily on small public land units in less densely populated regions of the state. Preferences for increased conservation/protection were over-represented in areas proximate to the Melbourne urban area and under-represented in more remote statewide locations. Our results indicate that if PPGIS data is to be integrated into spatial models for conservation planning, it is important to account for the spatial accuracy and completeness limitations identified in this study (i.e., urban areas, non-public lands, and smaller remote locations). The spatial accuracy and completeness of PPGIS data in this study suggests spatial data quality may be “good enough” to complement biological data in conservation planning but perhaps not good enough to overcome the mistrust associated with crowd-sourced knowledge. Recommendations to improve PPGIS data quality for prospective conservation planning applications are discussed.
In this paper, a general framework for the development of Decision Support Systems (DSSs) for the management of coastal lagoons is presented. The proposed DSS structure integrates the information provided by several models accounting for different characteristics of lagoon ecosystems, including biogeochemical, hydrodynamic, ecological and socio-economic aspects. Outputs and indicators provided by the models are used to accomplish the decision task by the application of multicriteria analysis. Model uncertainty and robustness with respect to uncontrollable factors are addressed. Application of the proposed DSS structure to five lagoons located in the Mediterranean area is discussed, with special focus on the management of clam farming in the Sacca di Goro lagoon (Italy). Thanks to its flexibility, the proposed DSS structure is also applicable in decision problems arising in different fields.
Fishing is altering aquatic ecosystems through changes in the abundance, species composition and behavior of target species. Changes in fish behavior have received relatively little attention, despite significant evidence of behavioral change driven by human impacts mediating function and processes in terrestrial ecosystems, and emerging evidence that the same is true in marine systems even within marine reserves. Here, we measured the wariness of two families of coral reef fishes in both fished areas and marine reserves embedded within a fished seascape along an exploitation gradient ranging from wilderness sites (Chagos) to heavily fished areas (the Philippines). We used linear mixed effect models to identify relationships between fish flight initiation distance (FID) and fishing pressure, fish size, habitat complexity and life-history stage. Critically, fish FID increased with fishing pressure both in fished areas and inside marine reserves. These results imply that as fishing pressure increases in adjacent areas, progressively greater fish wariness may reduce the magnitude of some ecosystem functions within small marine reserves.
Marine industries face a number of risks that necessitate careful analysis prior to making decisions on the siting of operations and facilities. An important emerging regulatory framework on environmental sustainability for business operations is the International Finance Corporation’s Performance Standard 6 (IFC PS6). Within PS6, identification of biodiversity significance is articulated through the concept of “Critical Habitat”, a definition developed by the IFC and detailed through criteria aligned with those that support internationally accepted biodiversity designations. No publicly available tools have been developed in either the marine or terrestrial realm to assess the likelihood of sites or operations being located within PS6-defined Critical Habitat. This paper presents a starting point towards filling this gap in the form of a preliminary global map that classifies more than 13 million km2 of marine and coastal areas of importance for biodiversity (protected areas, Key Biodiversity Areas [KBA], sea turtle nesting sites, cold- and warm-water corals, seamounts, seagrass beds, mangroves, saltmarshes, hydrothermal vents and cold seeps) based on their overlap with Critical Habitat criteria, as defined by IFC. In total, 5798×103 km2 (1.6%) of the analysis area (global ocean plus coastal land strip) were classed as Likely Critical Habitat, and 7526×103 km2 (2.1%) as Potential Critical Habitat; the remainder (96.3%) were Unclassified. The latter was primarily due to the paucity of biodiversity data in marine areas beyond national jurisdiction and/or in deep waters, and the comparatively fewer protected areas and KBAs in these regions. Globally, protected areas constituted 65.9% of the combined Likely and Potential Critical Habitat extent, and KBAs 29.3%, not accounting for the overlap between these two features. Relative Critical Habitat extent in Exclusive Economic Zones varied dramatically between countries. This work is likely to be of particular use for industries operating in the marine and coastal realms as an early screening aid prior to in situ Critical Habitat assessment; to financial institutions making investment decisions; and to those wishing to implement good practice policies relevant to biodiversity management. Supplementary material (available online) includes other global datasets considered, documentation and justification of biodiversity feature classification, detail of IFC PS6 criteria/scenarios, and coverage calculations.
This study provides an assessment of local government progress in adaptation to marine climate change in Australia׳s coastal communities. Globally, coastal communities are vulnerable to a diversity of marine climate change impacts, and adaptation responses will need to be tailored to suit each unique socio-ecological situation. The responsibility of adaptation planning is largely placed on municipal councils, yet much of this activity goes unreported in the peer-reviewed literature. Through a meta-analysis of municipal planning documents this study reveals that in general, progress is in the early stages. Many councils have no plans, and the presence of plans seems to be related to the magnitude of council income as well as participation in regional or international adaptation networks. Of those councils that do have plans, only half have progressed beyond the ‘understanding the problem’ phase. Additionally, the focus of marine adaptation planning is generally restricted to one driver – sea level rise. Changing sea surface temperatures and ocean acidification were largely ignored, despite predicted impacts on coastal ecosystems and the communities that interact and depend on them. While it is often assumed that developed countries have the capacity to adapt to climate change, this study indicates that for some important aspects of marine change in Australia, this capacity is not always translated into action by local councils. The development and refinement of progress indicators such as those used in this study will be increasingly important as tools for establishing baselines and tracking adaptation into the future.
The study aimed to describe and assess indicators that can potentially contribute to the development of Ecosystem-based Approach to Fisheries Management (EAFM) of prawn stocks in the Malindi-Ungwana Bay, the most productive coastal ecosystem in Kenya. A comprehensive EAFM is required to holistically manage fisheries resources and their associated habitats. The study assessed ecological indicators based on objectives of harvest sustainability and biodiversity conservation. Analyses were performed on data sourced from the State Department of Fisheries, and research databases. Trends in historical landings (1985–2010) of penaeid shrimps from the Malindi-Ungwana Bay were analyzed using LOWESS. Number-size spectra analysis was used to assess the exploitation status of the shrimps, while biomass-trophic level spectra (BTLS) analysis was applied as a potential tool for analyzing multifactor effects on the bay. IndiSeas-based ecosystem indicators were used to assess impact of the prawn trawl fishery on biodiversity of the bay. Results indicate long-term series with two peaks (1997 and 2000) in historical landings of penaeid shrimps and a monotonous decline in catches during 2002–2010. Slopes of number-size spectra suggested increased fishing mortality with time (2008–2012), while patterns of intercepts indicated a general increase in fisheries productivity of the bay. BTLS analysis using demersal fish survey and fish by-catch data suggested reduced levels of biomass across trophic levels and a temporal decline in trophic levels of fish species caught, however, the short time span constrains robust conclusions from the BTLS analysis. Biodiversity and conservation based indicators (e.g. fish sizes, trophic levels and proportion of predators in catches) adopted from the IndiSeas program showed the Malindi-Ungwana Bay to be ecologically degraded. There is need to initiate long-term monitoring programs to strengthen temporal scale of analysis of the datasets and to support use of ecological indicators for resource management and development of an EAFM in data-poor WIO countries.
Ornamental marine species (‘OMS’) provide valuable income for developing nations in the Indo-Pacific Coral Triangle, from which most of the specimens are exported. OMS culture can help diversify livelihoods in the region, in support of management and conservation efforts to reduce destructive fishing and collection practices that threaten coral reef and seagrass ecosystems. Adoption of OMS culture depends on demonstrating its success as a livelihood, yet few studies of OMS culture exist in the region. We present a case study of a land-based culture project for an endangered seahorse (Hippocampus barbouri) in the Spermonde Islands, Sulawesi, Indonesia. The business model demonstrated that culturing can increase family income by seven times. A Strengths Weaknesses Opportunities Threats (SWOT) analysis indicated good collaboration among diverse stakeholders and opportunities for culturing non-endangered species and for offshoot projects, but complicated permitting was an issue as were threats of market flooding and production declines. The OMS international market is strong, Indonesian exporters expressed great interest in cultured product, and Indonesia is the largest exporting country for H. barbouri. Yet, a comparison of Indonesia ornamental marine fish exports to fish abundance in a single local market indicated that OMS culture cannot replace fishing livelihoods. Nevertheless, seahorse and other OMS culture can play a role in management and conservation by supplementing and diversifying the fishing and collecting livelihoods in the developing nations that provide the majority of the global OMS.
Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species' response to stress depends on its life history. Sensitivity to harvesting is related to the life history “fast–slow” continuum, where “slow” species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than “fast” ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast–slow gradients obtained by ordination analyses. In addition, we integrate species' fast–slow ranks with ecosystem survey data for the period 2004–2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem-based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of these areas.
The giant bumphead parrotfish (Bolbometopon muricatum) has experienced precipitous population declines throughout its range due to its importance as a highly-prized fishery target and cultural resource. Because of its diet, Bolbometopon may serve as a keystone species on Indo-Pacific coral reefs, yet comprehensive descriptions of its reproductive ecology do not exist. We used a variety of underwater visual census (UVC) methods to study an intact population of Bolbometopon at Wake Atoll, a remote and protected coral atoll in the west Pacific. Key observations include spawning activities in the morning around the full and last quarter moon, with possible spawning extending to the new moon. We observed peaks in aggregation size just prior to and following the full and last quarter moon, respectively, and observed a distinct break in spawning at the site that persisted for four days; individuals returned to the aggregation site one day prior to the last quarter moon and resumed spawning the following day. The mating system was lek-based, characterized by early male arrival at the spawning site followed by vigorous defense (including head-butting between large males) of small territories. These territories were apparently used to attract females that arrived later in large schools, causing substantial changes in the sex ratio on the aggregation site at any given time during the morning spawning period. Aggression between males and courtship of females led to pair spawning within the upper water column. Mating interference was not witnessed but we noted instances suggesting that sperm competition might occur. Densities of Bolbometopon on the aggregation site averaged 10.07(±3.24 SE) fish per hectare (ha) with maximum densities of 51.5 fish per ha. By comparing our observations to the results of biennial surveys conducted by the National Oceanic and Atmospheric Administration (NOAA) Coral Reef Ecosystem Division (CRED), we confirmed spatial consistency of the aggregation across years as well as a temporal break in spawning activity and aggregation that occurred during the lunar phase. We estimated the area encompassed by the spawning aggregation to be 0.72 ha, suggesting that spawning site closures and temporal closures centered around the full to the new moon might form one component of a management and conservation plan for this species. Our study of the mating system and spawning aggregation behavior of Bolbometopon from the protected, relatively pristine population at Wake Atoll provides crucial baselines of population density, sex ratio composition, and productivity of a spawning aggregation site from an oceanic atoll. Such information is key for conservation efforts and provides a basic platform for the design of marine protected areas for this threatened iconic coral reef fish, as well as for species with similar ecological and life history characteristics.
While coral reefs are increasingly threatened worldwide, they are also increasingly used for recreational activities. Given the environmental and socio-economic significance of coral reefs, understanding the links between human activities and coral health and evaluating the efficacy of marine protected areas (MPAs) as a management regime to prevent further deterioration are critically important. The aim of this study was to quantify indicators of coral health at sites inside and outside a newly rezoned MPA framework in the dive tourism hotspot of Koh Tao, Thailand. We found that patterns in the health and diversity of coral communities one year on did not reflect the protected status conferred by newly zoned MPAs, but instead reflected past history of recreational use around the island. Sites characterised as past high-use sites had lower mean percent cover of hard corals overall and of corals in the typically disease- and disturbance-susceptible family Acroporidae, but higher mean cover of species in the more weedy family Agariciidae. Past high use sites also had higher mean prevalence of infectious diseases and other indicators of compromised health. Sites within the newly established MPAs are currently subjected to higher levels of environmental and anthropogenic pressures, with sedimentation, algal overgrowth, feeding scars from Drupella snails, and breakage particularly prevalent compared to sites in non-MPA areas. Given the greater prevalence of these factors within protected sites, the capacity of the MPA framework to effectively prevent further deterioration of Koh Tao's reefs is unclear. Nevertheless, our study constitutes a strong baseline for future long-term evaluations of the potential of MPAs to maintain coral health and diversity on highly threatened reefs.