scholarly journals A comparative baseline of coral disease across the central Red Sea

2021 ◽  
Author(s):  
Greta Smith Aeby ◽  
Amanda Shore ◽  
Thor Jensen ◽  
Maren Ziegler ◽  
Thierry Work ◽  
...  
Keyword(s):  
Red Sea ◽  
Coral Cover ◽  
Coral Disease ◽  
Negative Relationship ◽  
Cellular Level ◽  
Disease Prevalence ◽  
White Syndrome ◽  
Growth Anomalies ◽  
Disease Surveys ◽  
Black Band

AbstractThe Red Sea is a unique environment for corals with a strong environmental gradient characterized by temperature extremes and high salinities, but minimal terrestrial runoff or riverine input and their associated pollution. Disease surveys were conducted along 22 reefs in the central Red Sea along the Saudi Arabian coast in October 2015, which coincided with a bleaching event. Our objectives were to 1) document types, prevalence, and distribution of coral diseases in a region with minimal terrestrial input, 2) compare regional differences in diseases and bleaching along a latitudinal gradient of environmental conditions, and 3) use histopathology to characterize disease lesions at the cellular level. Coral reefs of the central Red Sea had a widespread but a surprisingly low prevalence of disease (<0.5%), based on the examination of >75,750 colonies. Twenty diseases were recorded affecting 16 coral taxa and included black band disease, white syndromes, endolithic hypermycosis, skeletal eroding band, growth anomalies and focal bleached patches. The three most common diseases were Acropora white syndrome (59.1% of the survey sites), Porites growth anomalies (40.9%), and Porites white syndrome (31.8%). Over half of the coral genera within transects had lesions and corals from the genera Acropora, Millepora and Lobophyllia were the most commonly affected. Cell-associated microbial aggregates were found in four coral genera resembling patterns found in the Indo-Pacific. Differences in disease prevalence, coral cover, amount of heat stress as measured by degree heating weeks (DHW) and extent of bleaching was evident among sites. Disease prevalence was not explained by coral cover or DHW, and a negative relationship between coral bleaching and disease prevalence was found. The northern-most sites off the coast of Yanbu had the highest average DHW values but absence of bleaching and the highest average disease prevalence was recorded. Our study provides a foundation and baseline data for coral disease prevalence in the Red Sea, which is projected to increase as a consequence of increased frequency and severity of ocean warming.

scholarly journals A comparative baseline of coral disease in three regions along the Saudi Arabian coast of the central Red Sea

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0246854
Author(s):  
Greta Smith Aeby ◽  
Amanda Shore ◽  
Thor Jensen ◽  
Maren Ziegler ◽  
Thierry Work ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Red Sea ◽  
Human Impacts ◽  
Coral Cover ◽  
Coral Disease ◽  
Saudi Arabian ◽  
Disease Prevalence ◽  
Coral Diseases ◽  
White Syndrome ◽  
Growth Anomalies

Coral disease is a growing problem for coral reefs globally and diseases have been linked to thermal stress, excess nutrients, overfishing and other human impacts. The Red Sea is a unique environment for corals with a strong environmental gradient characterized by temperature extremes and high salinities, but minimal terrestrial runoff or riverine input and their associated pollution. Yet, relatively little is known about coral diseases in this region. Disease surveys were conducted at 22 reefs within three regions (Yanbu, Thuwal, Al Lith) in the central Red Sea along the Saudi Arabian coast. Surveys occurred in October 2015, which coincided with a hyperthermal-induced bleaching event. Our objectives were to 1) document types, prevalence, and distribution of coral diseases in a region with minimal terrestrial input, 2) compare regional differences in diseases and bleaching along a latitudinal gradient of environmental conditions, and 3) use histopathology to characterize disease lesions at the cellular level. Coral reefs of the central Red Sea had a widespread but a surprisingly low prevalence of disease (<0.5%), based on the examination of >75,750 colonies. Twenty diseases were recorded affecting 16 coral taxa and included black band disease, white syndromes, endolithic hypermycosis, skeletal eroding band, growth anomalies and focal bleached patches. The three most common diseases were Acropora white syndrome (59.1% of the survey sites), Porites growth anomalies (40.9%), and Porites white syndrome (31.8%). Sixteen out of 30 coral genera within transects had lesions and Acropora, Millepora and Lobophyllia were the most commonly affected. Cell-associated microbial aggregates were found in four coral genera including a first report in Stylophora. Differences in disease prevalence, coral cover, amount of heat stress as measured by degree heating weeks (DHW) and extent of bleaching was evident among sites. Disease prevalence was not explained by coral cover or DHW, and a negative relationship between coral bleaching and disease prevalence was found. The northern-most sites off the coast of Yanbu had the highest average disease prevalence and highest average DHW values but no bleaching. Our study provides a foundation and baseline data for coral disease prevalence in the central Red Sea, which is projected to increase as a consequence of increased frequency and severity of ocean warming.

scholarly journals Ecological and molecular characterization of a coral black band disease outbreak in the Red Sea during a bleaching event

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5169 ◽  
Author(s):  
Ghaida Hadaidi ◽  
Maren Ziegler ◽  
Amanda Shore-Maggio ◽  
Thor Jensen ◽  
Greta Aeby ◽  
...  
Keyword(s):  
Microbial Community ◽  
Red Sea ◽  
Microbial Mats ◽  
Heterotrophic Bacteria ◽  
Coral Disease ◽  
Differential Susceptibility ◽  
Black Band Disease ◽  
Southern Central ◽  
Black Band

Black Band Disease (BBD) is a widely distributed and destructive coral disease that has been studied on a global scale, but baseline data on coral diseases is missing from many areas of the Arabian Seas. Here we report on the broad distribution and prevalence of BBD in the Red Sea in addition to documenting a bleaching-associated outbreak of BBD with subsequent microbial community characterization of BBD microbial mats at this reef site in the southern central Red Sea. Coral colonies with BBD were found at roughly a third of our 22 survey sites with an overall prevalence of 0.04%. Nine coral genera were infected including Astreopora, Coelastrea, Dipsastraea, Gardineroseris, Goniopora, Montipora, Pavona, Platygyra, and Psammocora. For a southern central Red Sea outbreak site, overall prevalence was 40 times higher than baseline (1.7%). Differential susceptibility to BBD was apparent among coral genera with Dipsastraea (prevalence 6.1%), having more diseased colonies than was expected based on its abundance within transects. Analysis of the microbial community associated with the BBD mat showed that it is dominated by a consortium of cyanobacteria and heterotrophic bacteria. We detected the three main indicators for BBD (filamentous cyanobacteria, sulfate-reducing bacteria (SRB), and sulfide-oxidizing bacteria (SOB)), with high similarity to BBD-associated microbes found worldwide. More specifically, the microbial consortium of BBD-diseased coral colonies in the Red Sea consisted of Oscillatoria sp. (cyanobacteria), Desulfovibrio sp. (SRB), and Arcobacter sp. (SOB). Given the similarity of associated bacteria worldwide, our data suggest that BBD represents a global coral disease with predictable etiology. Furthermore, we provide a baseline assessment of BBD disease prevalence in the Red Sea, a still understudied region.

scholarly journals 11-yr of coral community dynamics in reefs around Dahab (Gulf of Aqaba, Red Sea): the collapse of urchins and rise of macroalgae and cyanobacterial mats

Coral Reefs ◽  
2020 ◽  
Vol 39 (6) ◽  
pp. 1605-1618
Author(s):  
Miriam Reverter ◽  
Matthew Jackson ◽  
Nauras Daraghmeh ◽  
Christian von Mach ◽  
Nina Milton
Keyword(s):  
Coral Reef ◽  
Red Sea ◽  
Coral Cover ◽  
Negative Relationship ◽  
Gulf Of Aqaba ◽  
Benthic Fish ◽  
Hard Coral ◽  
Cyanobacterial Mats ◽  
Invertebrate Assemblages ◽  
Hard Coral Cover

AbstractCorals from the Gulf of Aqaba (northern Red Sea) are resilient to high temperatures and therefore this region is regarded as globally important for reef conservation. However, long-term dynamics of coral reef assemblages from the Gulf of Aqaba remain largely understudied. In this study, we analysed the change in benthic, fish and invertebrate assemblages of reefs around Dahab (South Sinai, Egypt) between 2009 and 2019. We also studied the individual trajectories of coral reef benthic categories, key invertebrate and fish species and their relationship. As site emerged as the main factor explaining the variability in coral reef communities, we identified three clusters of sites with similar assemblages. Both benthic, fish and invertebrate assemblages changed considerably at the three site clusters between 2009 and 2019. We found significant increases in fleshy macroalgae (~ 6 to 15%) and cyanobacterial mats (~ 6 to 12%) in all site clusters. Although not observing a significant reduction of hard coral cover, both macroalgae mat cover and cyanobacterial mat cover were significantly negatively related to hard coral cover and hard coral disease. Soft coral cover (mainly corals from the Xeniidae family) decreased significantly in two of the site clusters, their cover being negatively related to macroalgal and cyanobacterial cover. Significant declines in grazer urchins were observed at all site clusters, and a strong negative relationship was found with macroalgae and cyanobacterial mats cover, suggesting urchin decline as one of the main drivers behind algal increases. Different site clusters had different fish trajectories (butterflyfish, parrotfish, surgeonfish and predators), with only damselfish densities significantly decreasing at all sites. A significant decrease in damselfish densities was related to increases in cyanobacterial mats. These findings suggest that if macroalgae and cyanobacteria continue to increase, Dahab coral reefs could undergo degradation, and therefore, more studies are needed to elucidate the drivers behind these algal increases.

scholarly journals Coral Disease Time Series Highlight Size-Dependent Risk and Other Drivers of White Syndrome in a Multi-Species Model

2020 ◽  
Vol 7 ◽  
Author(s):  
Austin Greene ◽  
Megan J. Donahue ◽  
Jamie M. Caldwell ◽  
Scott F. Heron ◽  
Erick Geiger ◽  
...  
Keyword(s):  
Coral Disease ◽  
Negative Relationship ◽  
Coral Diseases ◽  
White Syndrome ◽  
Size Dependent ◽  
Multiple Species ◽  
Term Monitoring ◽  
Past Conditions

Coral diseases contribute to the decline of reef communities, but factors that lead to disease are difficult to detect. In the present study, we develop a multi-species model of colony-scale risk for the class of coral diseases referred to as White Syndromes, investigating the role of current or past conditions, including both environmental stressors and biological drivers at the colony and community scales. Investigating 7 years of coral survey data at five sites in Guam we identify multiple environmental and ecological associations with White Syndrome, including a negative relationship between short-term heat stress and White Syndrome occurrence, and strong evidence of increasing size-dependent White Syndrome risk across coral species. Our findings result in a generalized model used to predict colony-scale White Syndrome risk for multiple species, highlighting the value of long-term monitoring efforts to detect drivers of coral disease.

scholarly journals Baseline coral disease surveys within three marine parks in Sabah, Borneo

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1391 ◽  
Author(s):  
Jennifer Miller ◽  
Michael J. Sweet ◽  
Elizabeth Wood ◽  
John Bythell
Keyword(s):  
National Parks ◽  
Human Impacts ◽  
Coral Cover ◽  
Coral Disease ◽  
Strong Dependence ◽  
The Other ◽  
Coral Diseases ◽  
Disease Surveys ◽  
Different Levels ◽  
Study Offer

Two of the most significant threats to coral reefs worldwide are bleaching and disease. However, there has been a scarcity of research on coral disease in South-East Asia, despite the high biodiversity and the strong dependence of local communities on the reefs in the region. This study provides baseline data on coral disease frequencies within three national parks in Sabah, Borneo, which exhibit different levels of human impacts and management histories. High mean coral cover (55%) and variable disease frequency (mean 0.25 diseased colonies m−2) were found across the three sites. Highest disease frequency (0.44 diseased colonies per m2) was seen at the site closest to coastal population centres. Bleaching and pigmentation responses were actually higher at Sipadan, the more remote, offshore site, whereas none of the other coral diseases detected in the other two parks were detected in Sipadan. Results of this study offer a baseline dataset of disease in these parks and indicate the need for continued monitoring, and suggest that coral colonies in parks under higher anthropogenic stressors and with lower coral cover may be more susceptible to contracting disease.

scholarly journals Temperature stress and disease drives the extirpation of the threatened pillar coral, Dendrogyra cylindrus, in southeast Florida

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicholas P. Jones ◽  
Lystina Kabay ◽  
Kathleen Semon Lunz ◽  
David S. Gilliam
Keyword(s):  
Thermal Stress ◽  
Water Temperature ◽  
Coral Disease ◽  
Disease Prevalence ◽  
Syndrome Type ◽  
Conservation Area ◽  
White Syndrome ◽  
Stony Coral ◽  
Species Population ◽  
Dendrogyra Cylindrus

AbstractRare species population dynamics can elucidate the resilience of an ecosystem. On coral reefs, climate change and local anthropogenic stressors are threatening stony coral persistence, increasing the need to assess vulnerable species locally. Here, we monitored the threatened pillar coral, Dendrogyra cylindrus, population in southeast Florida, USA, in relation to consecutive heat stress events in 2014 and 2015. In the fall of each year, D. cylindrus colonies bleached following intense thermal stress and by June 2020 all monitored colonies died from a white-syndrome type disease. This resulted in the ecological extinction of D. cylindrus in the Southeast Florida Coral Reef Ecosystem Conservation Area (ECA). White-syndrome type disease was first seen in February 2014 on four colonies (19% prevalence) near the major international port, Port Everglades and disease prevalence peaked in fall 2015 (58%). Disease prevalence increased with maximum water temperature, while disease related mortality increased with mean water temperature. Our findings suggest that thermal stress exacerbated underlying stony coral disease, resulting in an outbreak contributing to the ecological extirpation of D. cylindrus in the ECA. We suggest that stony coral resilience is severely compromised by chronic environmental disturbance which hinders community recovery.

scholarly journals NON-RANDOM TIMING OF ECOLOGICAL SHIFTS ON CARIBBEAN CORAL REEFS SUGGESTS REGIONAL CAUSES OF CHANGE

2019 ◽  
Author(s):  
William F. Precht ◽  
Richard B. Aronson ◽  
Toby A. Gardner ◽  
Jennifer A. Gill ◽  
Julie P. Hawkins ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Nutrient Loading ◽  
Coral Cover ◽  
Coral Disease ◽  
Regional Scale ◽  
Negative Relationship ◽  
Grazing Pressure ◽  
Coral Mortality ◽  
Macroalgal Cover

AbstractCaribbean reefs have experienced unprecedented changes in the past four decades. Of great concern is the perceived widespread shift from coral to macroalgal dominance and the question of whether it represents a new, stable equilibrium for coral-reef communities. The primary causes of the shift -- grazing pressure (top-down), nutrient loading (bottom-up) or direct coral mortality (side-in) -- still remain somewhat controversial in the coral reef literature. We have attempted to tease out the relative importance of each of these causes. Four insights emerge from our analysis of an early regional dataset of information on the benthic composition of Caribbean reefs spanning the years 1977–2001. First, although three-quarters of reef sites have experienced coral declines concomitant with macroalgal increases, fewer than 10% of the more than 200 sites studied were dominated by macroalgae in 2001, by even the most conservative definition of dominance. Using relative dominance as the threshold, a total of 49 coral-to-macroalgae shifts were detected. This total represents ∼35% of all sites that were dominated by coral at the start of their monitoring periods. Four shifts (8.2%) occurred because of coral loss with no change in macroalgal cover, 15 (30.6%) occurred because of macroalgal gain without coral loss, and 30 (61.2%) occurred owing to concomitant coral decline and macroalgal increase. Second, the timing of shifts at the regional scale is most consistent with the side-in model of reef degradation, which invokes coral mortality as a precursor to macroalgal takeover, because more shifts occurred after regional coral-mortality events than expected by chance. Third, instantaneous observations taken at the start and end of the time-series for individual sites showed these reefs existed along a continuum of coral and macroalgal cover. The continuous, broadly negative relationship between coral and macroalgal cover suggests that in some cases coral-to-macroalgae phase shifts may be reversed by removing sources of perturbation or restoring critical components such as the herbivorous sea urchin Diadema antillarum to the system. The five instances in which macroalgal dominance was reversed corroborate the conclusion that macroalgal dominance is not a stable, alternative community state as has been commonly assumed. Fourth, the fact that the loss in regional coral cover and concomitant changes to the benthic community are related to punctuated, discrete events with known causes (i.e. coral disease and bleaching), lends credence to the hypothesis that coral reefs of the Caribbean have been under assault from climate-change-related maladies since the 1970s.

Coral disease prevalence and coral health in the Wakatobi Marine Park, south-east Sulawesi, Indonesia

2007 ◽  
Vol 87 (2) ◽  
pp. 403-414 ◽  
Author(s):  
J. Haapkylä ◽  
A.S. Seymour ◽  
J. Trebilco ◽  
D. Smith
Keyword(s):  
Coral Disease ◽  
Disease Prevalence ◽  
Coral Diseases ◽  
White Spot Disease ◽  
Marine Park ◽  
Black Band ◽  
Baseline Knowledge ◽  
Coral Health ◽  
Taxonomic Groups ◽  
The Impact

This is the first study on coral diseases in the Wakatobi Marine National Park (WMNP), south-east Sulawesi. It aimed to provide baseline knowledge of coral disease prevalence and coral health in this remote region. Results indicate a low disease prevalence of 0.57% with only two known diseases occurring within the sampling unit, white syndrome (0.42%) and tumours (0.15%). They affected 15 taxonomic groups from a total of 32 taxonomic groups. The presence of black-band disease (BBD), skeletal eroding band (SEB) disease and Porites ulcerative white spot disease (PUWSD) was identified outside the study area. A large number of corals were affected by previously undescribed conditions (9.7% of colonies). The impact of lesions named as green spot, green band, pigmented spot, and flatworm infestation is not known and represents an important area for future studies.

scholarly journals Scleractinian Coral Health Status of Padang Shelf Reef System, West Sumatera, Indonesia (Status Kesehatan Karang Skleraktinian pada Sistem Terumbu Karang Pesisir di Perairan Padang, Sumatera Barat, Indonesia)

2015 ◽  
Vol 19 (4) ◽  
pp. 181
Author(s):  
Ofri Johan ◽  
Amran R Syam
Keyword(s):  
Health Status ◽  
Coral Disease ◽  
Patch Reef ◽  
Black Band Disease ◽  
White Syndrome ◽  
Reef System ◽  
Black Band ◽  
Coral Health ◽  
A Minor ◽  
Pocillopora Verrucosa

Prevalensi penyakit karang sebelumnya belum dilaporkan di perairan Padang, Sumatera Barat. Adapun tujuan penelitian ini adalah untuk mendapatkan prevalensi penyakit karang pada lokasi yang dekat dengan pantai, pertengahan dan lokasi terluar, dimana lokasi tersebut merupakan lokasi pemantauan yang berkesinambungan sejak tahun 1994 untuk data kondisi karang. Metode pengamatan yang digunakan adalah metode transek sabuk dengan ukuran 1 m kekiri dan kekanan transek garis yang memiliki panjang 30 m dan 3 ulangan. Dua jenis penyakit dan dua indicator stress karang teramati pada penelitian ini. Penyakit karang sabuk hitam (Black Band Disease, BBD) yang banyak ditemukan di Pulau Pandan (1.3%) pada kedalam 5 m. Penyakit White Syndrome (WS) terjadi di Gosong Air (0.3%). Beberapa koloni karang Montipora sp. dan Pocillopora verrucosa mengalami pemutihan di Pulau Pieh (2.1%).Focal bleaching ditemukan pada karang Galaxea sp. dan Goniastrea sp. di Gosong Gabuo (2.5%) dan pada karang Pocillopora verrucosa di Gosong Sipakal (3.9%). Penyakit BBD menginfeksi karang Montipora sp. dan Porites sp. Penyakit WS hanya menginfeksi karang Montipora sp. Karang Montipora sp, Pocillopora sp dan Porites sp banyak dan umum ditemukan di perairan Padang. Hasil ini menunjukkan bahwa infeksi penyakit karang masih tergolong rendah dan secara alamiah bisa terjadi sehingga tidak menghalangi proses pemulihan kondisi karang yang saat ini terjadi dan secara umum pada status kesehatan karang. Kata kunci: coral disease, black band disease, white syndrome, Sumatera Barat The prevalence of coral disease was previously unreported on the reefs of the Padang Shelf Reef System, West Sumatra and is relatively uncommon. The objective of this study was to get coral disease prevalence of each site which located at inshore, mid-shelf reef and off-shore reefs. The research was carried out by using belt transect method with 1 m left and right of tape as long 30 m with 3 replications. Two kinds of coral disease and two indicators of stressed coral were observed. While relatively infrequent, Black Band Disease was most common (1.3%) occurring on Pandan Island at 5m. White Syndrome occurred at Air patch reef (0.3%). A few bleached colonies of Montipora sp. and Pocillopora verrucosa were observed on Pieh Island reef (2.1%). Focal bleaching was observed on Galaxea sp. and Goniastrea sp. at Gabuo patch reefs (2.5%) and on Pocillopora verrucosa at Sipakal patch reef (3.9%). BBD infected both Montipora sp. and Porites sp. WS only infected on Montipora sp. Montipora, Pocillopora and Porites were the most common genera observed on the reefs. It suggests that coral disease infection was classified as a minor and it will not hamper coral recovery processes and coral health status in Padang Waters, West Sumatera. Keywords: coral disease, black band disease, white syndrome, West Sumatera

scholarly journals Coral Disease and the Environment in the  Pacific Ocean

2021 ◽  
Author(s):  
◽  
Gareth John Williams
Keyword(s):  
Environmental Conditions ◽  
Human Population ◽  
Coral Cover ◽  
Spatial Scales ◽  
Coral Disease ◽  
Host Density ◽  
Tissue Loss ◽  
Coral Diseases ◽  
Growth Anomalies ◽  
Growth Anomaly

<p>Coral diseases are a major threat to coral reef health and functioning worldwide. Little is known about how coral disease prevalence relates to multiple interacting changes in host densities, abiotic stressors, and levels of human impact. In particular, almost nothing is known about coral disease dynamics under changing abiotic conditions in the absence of direct anthropogenic stressors. Understanding how disease dynamics change relative to shifts in environmental conditions is crucial for the successful management and future survival of coral reefs. With the use of existing and novel field data and statistical modeling I examined the associations (abiotic and biotic) of multiple coral disease states across a variety of spatial scales encompassing a wide range of environmental conditions. Biomedical techniques were then used to relate these environmental associations to potential disease etiology. Study sites included areas with high levels of anthropogenic impact (e.g. Oahu, main Hawaiian Islands); to extremely remote quasi-pristine reefs removed from direct human influence (e.g. Palmyra Atoll National Wildlife Refuge). Over small spatial scales (100s m) at a marine reserve in the main Hawaiian Islands I modelled the spatial patterns of four coral diseases (Porites growth anomalies, Porites tissue loss, Porites trematodiasis and Montipora white syndrome). While Porites tissue loss and Montipora white syndrome were positively associated with poor environmental conditions (poor water quality, low coral cover), Porites growth anomalies and Porites trematodiasis were more prevalent in areas considered to be of superior quality (clearer water, increased host abundance, higher numbers of fish). At Palmyra Atoll, fatal tissue loss diseases were largely absent and although coral growth anomalies were present their prevalence was extremely low. Patterns of growth anomaly prevalence at Palmyra were positively associated with host abundance across four coral genera (Acropora, Astreopora, Montipora and Porites) and generally negatively associated with algal cover. Growth anomalies, although progressive and detrimental to the hosts, were most prevalent in the "healthiest" regions (the highest coral cover regions) of Palmyra. I hypothesised that differences seen in the types and prevalence of coral diseases between heavily populated parts of Hawaii and remote uninhabited locations such as Palmyra Atoll, could be a result of differing levels of either direct (e.g. pollution) or indirect (e.g. pollution leading to loss of key hosts) human stressors, in addition to natural changes in the environment. To begin disentangling the confounding effects of natural variability and human stressors on coral disease prevalence patterns I modelled two diseases (Acropora and Porites growth anomalies) across hundreds of sites throughout the Indo-Pacific Ocean (1000s km). Predictors included host densities, human population numbers, frequency of sea surface temperature anomalies, and input of ultra-violet radiation. Porites growth anomaly prevalence was positively associated with human population density (and to a lesser extent host density), while the prevalence of Acropora growth anomalies was strongly host density dependent. The positive association between the prevalence of Porites growth anomalies and human density suggests the presence and prevalence of the disease are related, directly or indirectly, to some environmental co-factor associated with increased human density at regional spatial scales. Although this association has been widely posited, this is one of the first wide scale studies unambiguously linking a coral disease with human population size. In summary, the types of coral diseases observed, their prevalence, and spatial patterns of distribution within reef systems are the result of multiple abiotic and biotic factors and stressors interacting, in some cases synergistically. Statistical modelling, in conjunction with biomedical techniques and field observations, proved essential to the understanding of coral disease ecology within single reefs and atolls to patterns across entire oceans.</p>

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