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Sweet M.J.,University of Derby | Sere M.G.,ARVAM | Sere M.G.,Oceanographic Research Institute ORI | Sere M.G.,Center Reunion
Journal of Sea Research | Year: 2015

Incidences of coral disease are increasing. Most studies which focus on diseases in these organisms routinely assess variations in bacterial associates. However, other microorganism groups such as viruses, fungi and protozoa are only recently starting to receive attention. This study aimed at assessing the diversity of ciliates associated with coral diseases over a wide geographical range. Here we show that a wide variety of ciliates are associated with all nine coral diseases assessed. Many of these ciliates such as Trochilia petrani and Glauconema trihymene feed on the bacteria which are likely colonizing the bare skeleton exposed by the advancing disease lesion or the necrotic tissue itself. Others such as Pseudokeronopsis and Licnophora macfarlandi are common predators of other protozoans and will be attracted by the increase in other ciliate species to the lesion interface. However, a few ciliate species (namely Varistrombidium kielum, Philaster lucinda, Philaster guamense, a Euplotes sp., a Trachelotractus sp. and a Condylostoma sp.) appear to harbor symbiotic algae, potentially from the coral themselves, a result which may indicate that they play some role in the disease pathology at the very least. Although, from this study alone we are not able to discern what roles any of these ciliates play in disease causation, the consistent presence of such communities with disease lesion interfaces warrants further investigation. © 2015.

Sere M.G.,Agence Pour la Recherche et la Valorisation Marines ARVAM | Sere M.G.,Oceanographic Research Institute ORI | Sere M.G.,Institute Of La Recherche Pour Le Developpement Ird | Tortosa P.,University of Reunion Island | And 4 more authors.
PLoS ONE | Year: 2013

The scleractinian coral Porites lutea, an important reef-building coral on western Indian Ocean reefs (WIO), is affected by a newly-reported white syndrome (WS) the Porites white patch syndrome (PWPS). Histopathology and culture-independent molecular techniques were used to characterise the microbial communities associated with this emerging disease. Microscopy showed extensive tissue fragmentation generally associated with ovoid basophilic bodies resembling bacterial aggregates. Results of 16S rRNA sequence analysis revealed a high variability between bacterial communities associated with PWPS-infected and healthy tissues in P. lutea, a pattern previously reported in other coral diseases such as black band disease (BBD), white band disease (WBD) and white plague diseases (WPD). Furthermore, substantial variations in bacterial communities were observed at the different sampling locations, suggesting that there is no strong bacterial association in Porites lutea on WIO reefs. Several sequences affiliated with potential pathogens belonging to the Vibrionaceae and Rhodobacteraceae were identified, mainly in PWPS-infected coral tissues. Among them, only two ribotypes affiliated to Shimia marina (NR043300.1) and Vibrio hepatarius (NR025575.1) were consistently found in diseased tissues from the three geographically distant sampling localities. The role of these bacterial species in PWPS needs to be tested experimentally. © 2013 Séré et al.

Sere M.G.,Agence Pour la Recherche et la Valorisation Marines ARVAM | Sere M.G.,Oceanographic Research Institute ORI | Sere M.G.,IRD Montpellier | Tortosa P.,University of Reunion Island | And 4 more authors.
Molecular Ecology | Year: 2015

Porites white patch syndrome (PWPS) is a coral disease recently described in the Western Indian Ocean. This study aimed to isolate and identify potential pathogens associated with PWPS utilizing both culture and nonculture screening techniques and inoculation trials. A total of 14 bacterial strains (those dominant in disease lesions, absent or rare in healthy tissues and considered potential pathogens in a previous study) were cultured and used to experimentally inoculate otherwise healthy individuals in an attempt to fulfil Henle-Koch's postulates. However, only one (P180R), identified as closely related (99-100% sequence identity based on 1.4 kb 16S RNA sequence) to Vibrio tubiashii, elicited signs of disease in tank experiments. Following experimental infection (which resulted in a 90% infection rate), the pathogen was also successfully re-isolated from the diseased tissues and re-inoculated in healthy corals colonies, therefore fulfilling the final stages of Henle-Koch's postulates. Finally, we report that PWPS appears to be a temperature-dependent disease, with significantly higher tissue loss (anova: d.f. = 2, F = 39.77, P < 0.01) occurring at 30 C [1.45 ± 0.85 cm2 per day (mean ± SE)] compared to ambient temperatures of 28 and 26 C (0.73 ± 0.80 cm2 per day (mean ± SE) and 0.51 ± 0.50 cm2 per day (mean ± SE), respectively). © 2015 John Wiley and Sons Ltd.

Dunlop S.,Oceanographic Research Institute ORI | Dunlop S.,University of KwaZulu - Natal | Mann B.,Oceanographic Research Institute ORI
African Journal of Marine Science | Year: 2013

This study evaluates trends in participation, catch and effort in the KwaZulu-Natal offshore boat-based linefishery. Methods used included a random access-point survey and an associated questionnaire survey. The study was undertaken between February 2009 and April 2010. Total participation in all sectors (recreational, charter and commercial) ranged between 18 217 and 20 546 boat-fishers and between 2 582 and 3 326 boats. Similarly, total fisher effort in the offshore linefishery was estimated at 39 664 boat-outings y-1. The commercial boat sector had the highest catch per unit effort (CPUE) both numerically (307.4 fish outing-1) and by weight (235.6 kg outing-1). In contrasting, the recreational boat sector had the lowest CPUE both numerically (8.6 fish outing-1) and by weight (15.0 kg outing-1). In total, 86 fish species, belonging to 27 families, were recorded in catches of boat-fishers (all sectors) during the study period. Catch composition was similar with Chrysoblephus puniceus, Chrysoblephus anglicus and Lethrinus nebulosus being represented in the top five species of all three fishery sectors. Analysis of overall CPUE, catch composition and total catch of the offshore boat-based linefishery in KZN suggested that the fishery is currently in a relatively stable condition and that little change has occurred over the past 13 years. However, specific CPUE values from this study together with those reported in the literature suggest that some species may be severely overexploited. It is recommended that stock assessments of the priority species should be conducted in the near future and steps should be taken to encourage rebuilding of overexploited species. This must include urgent regulation of the burgeoning charter boat-fishery as well as increased attempts to establish more marine protected areas. © 2013 Copyright NISC (Pty) Ltd.

Sere M.G.,ARVAM | Sere M.G.,Oceanographic Research Institute ORI | Sere M.G.,Center Reunion | Chabanet P.,Center Reunion | And 3 more authors.
Diseases of Aquatic Organisms | Year: 2015

Coral diseases have caused a substantial decline in the biodiversity and abundance of reef-building corals. To date, more than 30 distinct diseases of scleractinian corals have been reported, which cause progressive tissue loss and/or affect coral growth, reproductive capacity, recruitment, species diversity and the abundance of reef-associated organisms. While coral disease research has increased over the last 4 decades, very little is known about coral diseases in the Western Indian Ocean. Surveys conducted at multiple sites in Reunion, South Africa and Mayotte between August 2010 and June 2012 revealed the presence of 6 main coral diseases: black band disease (BBD), white syndrome (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). Overall, disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%) and Mayotte (2.7 ± 0.3%). Across locations, Acropora and Porites were the genera most susceptible to disease. Spatial variability was detected in both Reunion and South Africa, with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in 2 diseases: the prevalence of BBD and WS was higher in summer than winter. This was the first study to investigate the ecology of coral diseases, providing both qualitative and quantitative data, on Western Indian Ocean reefs, and surveys should be expanded to confirm these patterns. © Inter-Research 2015.

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