Australian Institute Of Marine Science Research Articles

Spatial and temporal predictions of inter-decadal trends in Indian Ocean whale sharks

We thank the purse-seine vessel owners for access to log-book data and to the Indian Ocean Tuna Commission and the Institut de Recherche pour le Developpement (France), in particular A. Fonteneau, M. Herrera and R. Pianet for data extraction and D. Rowat for data availability and help with interpretation. Our study was funded by Fundacao para a Ciencia e Tecnologia and European Social Funds through A.M.M.S.'s PhD scholarship (SFRH/BD/47465/2008), The University of Adelaide, Australian Institute of Marine Science, Flying Sharks and the Portuguese Association for the Study and Conservation of Elasmobranchs.

Dispatches

Dispatches

Science, monitoring and management for offshore petroleum activities

The Australian Institute of Marine Science is a publicly funded research agency that provides scientific expertise to support the sustainable use and protection of the marine environment through innovative world-class scientific and technological research.

NOAA's Coral Reef Watch program from satellite observations

The NOAA Coral Reef Watch (CRW) program uses near-real-time satellite measurements of sea surface temperature (SST) to monitor thermal stress of the coral reefs. These data provide up-to-date measurements pinpointing areas that are currently at risk for thermally induced coral bleaching. All of CRW's products can be accessed through CRW's Web portal at http://coralreefwatch.noaa.gov. Ongoing examination of tropical SSTs reveal regionally diverse but changing SST patterns and trends. In 2005 and 2010, two record-breaking thermal stress events occurred throughout much of the eastern Caribbean (Wilkinson and Souter 2008. Status of Caribbean coral reefs after bleaching and hurricanes in 2005. Townsville, Australia: Global Coral Reef Monitoring Network, and Reef and Rainforest Research Centre, 152; Eakin et al.2010. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005. PLoS One, 5, e13969). In 1998 and 2010, record-breaking bleaching occurred in all tropical oceans (Wilkinson 2000. Status of coral reefs of the world 2000, Townsville, Australia: Australian Institute of Marine Science, 375). With global satellite SSTs spanning more than two decades, we now have sufficient data to examine global- and basin-scale trends. The development and production of these CRW products takes place within National Oceanic and Atmospheric Administration's National Environmental Satellite, Data, and Information Service (NESDIS). This NESDIS team is comprised of scientists from the Marine Ecosystem & Climate Branch in the Satellite Oceanography & Climatology Division of the Center for Satellite Applications & Research and from personnel within NESDIS' Office of Satellite Products and Operations.

Environmental and spatial predictors of species richness and abundance in coral reef fishes

Funding was provided by the Australian Commonwealth Environment Research Facilities (CERF) programme (partners include the University of Tasmania, CSIRO, Geoscience Australia, the Australian Institute of Marine Science and Museum Victoria). We thank all members of the Australian Institute of Marine Science Long-Term Monitoring Program who have contributed to data collection. We are grateful to B. Venables, R. Pitcher, N. Bax and M. Hughes for their insights and suggestions.

Editorial and retrospective 2010

Editorial and retrospective 2010

A new conceptual model for the enhanced release of mucus in symbiotic reef corals during ‘bleaching’ conditions

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 396:145-152 (2009) - DOI: https://doi.org/10.3354/meps08310 NOTE A new conceptual model for the enhanced release of mucus in symbiotic reef corals during ‘bleaching’ conditions Scott A. Wooldridge* Australian Institute of Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia *Email: s.wooldridge@aims.gov.au ABSTRACT: Symbiotic reef corals exude large volumes of mucus when exposed to environmental conditions that challenge the integrity of the coral-algae endosymbiosis. Here, the physiological consequences of CO2-limitation within the ‘dark’ photosynthetic reactions of the algal endosymbionts (‘zooxanthellae’) are investigated as the possible cause of the release of 2 different forms of mucus: mucus-polysaccharide and mucus-lipid. This mechanism may explain why the experimental addition of specific host-derived free amino acids (commonly referred to as ‘host factors’) enhances photosynthate release and carbon fixation rates from in vitro zooxanthellae. Furthermore, it reinforces the often-ignored importance of the coral host in maintaining the stability and functioning of the intact symbiosis in the face of environmental stress, even supporting the possibility that disruption to host-controlled processes ultimately triggers the breakdown of the symbiosis leading to the mass expulsion of zooxanthellae (‘coral bleaching’). KEY WORDS: Coral bleaching · Host release factor · Photoinhibition · Lipogenesis Full text in pdf format PreviousNextCite this article as: Wooldridge SA (2009) A new conceptual model for the enhanced release of mucus in symbiotic reef corals during ‘bleaching’ conditions. Mar Ecol Prog Ser 396:145-152. https://doi.org/10.3354/meps08310 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 396. Online publication date: December 09, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Whither coast and wetland research?

It is difficult to synthesis an overall picture of the research work that is in progress on coast and wetland systems in Australia. As usual with scientific endeavour most of the projects appear to be highly specialised, fragmented and unco-ordinated. Indeed, one wonders if any attempt is being made to bring complementary scientific results together so that a more holistic view can begin to appear. The amounts of money being expended on marine research in Australia are quite substantial. Funding of research in marine sciences and technologies by the Australian Institute of Marine Science, the CSIRO and the Antartic Division of the Department of Science and Technology totalled $18.7 million for 1982. In addition $1.9 million were allocated for research projects in tis area to a variety of government and educational institutions. This can be compared into $17.9 million allocated by the Australian Research Grants Committee and $34.9 million allocated under the National Water Resources programme.

Differences in benthic cover inside and outside marine protected areas on the Great Barrier Reef: influence of protection or disturbance history?

Abstract Marine protected areas (MPAs) are being used increasingly to manage and protect marine resources. Most studies of MPAs have focused on fish. In this study, the influence of MPA protection on coral reef benthic organisms on the Great Barrier Reef (GBR) was investigated. In addition, the interaction between protection and natural disturbance history was examined. Differences in benthic cover inside and outside MPAs were assessed at 15 pairs of Protected and General Use reefs on the GBR using annual monitoring data from the Australian Institute of Marine Science's Long‐Term Monitoring Programme (LTMP). At each reef, benthic cover was determined using a benthic video survey at three sites, with each site consisting of five 50 m transect lines separated by at least 250 m running parallel to the reef crest at 6–9 m depth. Benthic cover was related to both protection status and disturbance history, but natural perturbations exerted a stronger influence on benthic cover than did protection status. The influence of natural perturbation was most noticeable for hard coral. Most reefs where no natural disturbance events had occurred (‘undisturbed reefs’) had higher hard coral cover and lower soft coral cover than General Use reefs. While the high levels of hard coral on Protected reefs may be a result of protection status, it might also have resulted from selection bias that occurred during the initial zoning of the Great Barrier Reef Marine Park (i.e. managers may have given protection status to reefs with high coral cover). These results are likely influenced by the relatively low intensity of human use, both on the Great Barrier Reef in general and at the particular monitoring sites studied. Over time, as local populations and tourism increase, the effect of protection may become more evident at LTMP sites. Copyright © 2009 John Wiley & Sons, Ltd.

Coral calcification from skeletal records revisited

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 373:257-264 (2008) - DOI: https://doi.org/10.3354/meps07398 Contribution to the Theme Section ‘Effects of ocean acidification on marine ecosystems’ Coral calcification from skeletal records revisited Janice M. Lough* Australian Institute of Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia *Email: j.lough@aims.gov.au ABSTRACT: Skeletal growth records in annually banded massive coral skeletons are an under-exploited archive of coral responses to environmental changes. Average linear extension and calcification rates in Indo-Pacific Porites are linearly related to average water temperatures through 23 to 30°C. Assessing long-term trends in Porites extension and density requires caution as there is evidence of an age effect whereby in earlier growth years corals will tend to extend less and form a higher density skeleton than in later years. This does not appear to affect calcification rates. Coral growth characteristics at 2 of 3 reefs in the central Great Barrier Reef provide evidence of a recent decline. This is of concern, although the exact causes cannot be identified. International efforts are required to make full use of both coral growth histories and geochemical tracers contained in massive coral skeletons to understand the nature and significance of recent trends and their possible links with environmental changes such as ocean chemistry, warming tropical oceans and increased frequency of coral bleaching events. KEY WORDS: Coral calcification · Porites · Temperature · Climate · Great Barrier Reef Full text in pdf format PreviousNextCite this article as: Lough JM (2008) Coral calcification from skeletal records revisited. Mar Ecol Prog Ser 373:257-264. https://doi.org/10.3354/meps07398Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 373. Online publication date: December 23, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Recovery from disturbance of coral and reef fish communities on the Great Barrier Reef, Australia

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 371:177-190 (2008) - DOI: https://doi.org/10.3354/meps07657 Recovery from disturbance of coral and reef fish communities on the Great Barrier Reef, Australia M. J. Emslie*, A. J. Cheal, H. Sweatman, S. Delean Australian Institute of Marine Science, PMB No. 3, Townsville Mail Centre, Townsville, Queensland 4810, Australia *Email: m.emslie@aims.gov.au ABSTRACT: Coral reefs are consistently and increasingly subject to acute disturbance events that often lead to a reduction in live coral cover with concomitant effects on the diversity and abundance of coral reef fishes. Here we examine changes in both hard coral and reef-fish assemblages over 15 yr following major losses of coral from exposed reefs in 2 widely separated sectors of the Great Barrier Reef (GBR), Australia. While the rate and extent of increase in coral cover (from <15 to >60%) was similar in the 2 sectors, differences in the rugosity of the underlying reef framework influenced the structure of fish communities. Soon after disturbance, when coral cover was very low and the limestone reef framework constituted most of the surface relief, the relatively featureless substrate on reefs of the southern sector supported fewer fish species than reefs of the northern sector, which had a more rugose substrate. At first, northern reefs also had a higher proportion of herbivorous fish species, presumably because the more complex reef surface provided shelter and allowed them to exploit the abundant algal turf. With increasing coral cover, coral colonies came to provide most of the surface relief in both sectors, and species richness and the trophic structure of the fish communities converged. Variation in the cover of branching corals explained significant variation in the fish communities in both sectors over time, reflecting the importance of this growth form to small coral-associated fishes. These results show that the recovery of the coral community and the complexity of underlying reef framework interact to determine the functional structure of associated fish communities despite differences in regional settings. KEY WORDS: Coral disturbance · Coral recovery · Fish communities · Trophic · Great Barrier Reef · Storm damage Full text in pdf format PreviousNextCite this article as: Emslie MJ, Cheal AJ, Sweatman H, Delean S (2008) Recovery from disturbance of coral and reef fish communities on the Great Barrier Reef, Australia. Mar Ecol Prog Ser 371:177-190. https://doi.org/10.3354/meps07657 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 371. Online publication date: November 19, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Spiny lobster development: mechanisms inducing metamorphosis to the puerulus: a review

This review outlines current knowledge of mechanisms effecting metamorphosis in decapod crustaceans and insects. The comparative approach demonstrates some of the complexities that need resolving to find an answer to the question raised frequently by ecologists: “What triggers metamorphosis in spiny lobsters?” It is evident that crustacean moulting and metamorphosis are genetically controlled through endocrine systems that mediate gene expression. The molecular mechanisms underlying these developmental processes have been studied intensively in insects, particularly in the fruitfly, Drosophila melanogaster (Diptera), and some lepidopteran species. Comparatively, there is minimal information available for a few decapod crustacean species, but none for spiny lobsters (Palinuridae). Nothing was known of hormone signalling transduction pathways, via nuclear receptors (NRs) and gene activation during larval moults in palinurids—until a recent, ground-breaking study of early phyllosomal development of Panulirus ornatus by Wilson et al. (Rock Lobster Enhancement and Aquaculture Subprogram. FRDC Project 2000/263, Australian Govt, Fisheries Research and Development Corporation and Australian Institute of Marine Science, Nov 2005). Their study not only identified homologues of five hormone NRs of D. melanogaster, but also patterns of gene regulation showing strong similarities to those of gene expression found in insect larval development. Their results indicated that control of moulting and metamorphosis in palinurids closely parallels that in insects, suggesting that insects can serve as model systems for elucidating molecular mechanisms in larval decapods. In insects and crustaceans, the steroid hormone, ecdysone, (20E) initiates moulting. In insects, juvenile hormone (JH) mediates the type of larval moult that occurs, either anamorphic or metamorphic. The latter results when the level of JH in the haemolymph drops in the final larval instar. High levels of JH inhibit the metamorphic moult during insect larval development. The interaction of 20E and JH is not fully understood, and the operative molecular mechanisms are still being elucidated. No nuclear receptor for JH has been identified, and alternative JH signalling pathways await identification. In decapod crustaceans, methyl farnesoate (MF), a precursor of JH, replaces the latter in other functions mediated by JH in insects; but there is little evidence indicating that MF plays a similar ‘antimetamorphic’ role in decapod larval moults.

Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 322:61-73 (2006) - doi:10.3354/meps322061 Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia Sven Uthicke* Australian Institute of Marine Science, PMB No. 3, Townsville, Queensland 4810, Australia *Email: s.uthicke@aims.gov.au ABSTRACT: The use of pulse-amplitude modulated (PAM) fluorometry in situ and in vivo as an indicator for nutrient and light status of microphytobenthos communities was investigated on the Great Barrier Reef. The 10 reefs investigated were located along a previously described water quality gradient, confirmed by sediment chemistry parameters (Corg, N) and incident light measurements. Estimates of the efficiency of Photosystem II (PSII) were biased when not corrected for background fluorescence that increased with increasing inorganic C content of the sediments. Uncorrected values mimicked a decline in quantum efficiency towards areas with presumed lower nutrient levels. Upon correction, maximum and effective quantum efficiency (ca. 0.59) did not vary significantly along the gradient. The maximum quantum efficiency (Fv/Fm,corr) measured after dark-adaptation did not differ statistically from effective quantum efficiency in the field (φPSII,corr). F0 values measured in the laboratory were much lower than in situ F readings, indicating a higher concentration of biomass on the surface of the sediment in the field. Rapid light curve parameters (initial slope α, relative electron transport rate at light saturation rETRmax, irradiance at onset of light saturation Ek) were lower during in vitro readings than in situ. rETRmax and α values exhibited no statistical differences along the gradient. In contrast, Ek increased towards midshelf reefs and correlated with incident PAR, indicating that microphytobenthos communities were highly adapted to incident light conditions. Because coral reef microphytobenthos was previously shown to be nitrogen limited, it was unexpected that efficiency measurements would not vary. It is hypothesised that, due to potential for differential vertical migration, the actual species involved in photosynthesis at a given time are nutrient sufficient. Higher nutrient supply may change the community composition on the surface to dominance by species with higher productivity. KEY WORDS: PAM · WQ gradient · Benthic microalgae (BMA) · Nutrient limitation · Light limitation Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 322. Online publication date: September 20, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

Trace analysis of hydrocarbons in coral cores from Saudi Arabia

As part of a long-term environmental assessment of the impact of the 1991 Gulf War on coral reefs, the Australian Institute of Marine Science (AIMS) conducted growth and chemistry studies on coral cores from the Arabian Gulf. Twenty-eight cores were collected from four coral reefs located offshore from Saudi Arabia. Annual coral growth bands surrounding the 1991 oil spill were analysed in selected cores. Additionally, in cores that extended to the early 1980s, annual layers from 1980 to 1986 were analysed for possible residues from the 1983–4 oil spill caused by the Nowruz oil field blowout during the Iraq–Iran war. Both major spill events were targeted to provide additional confidence in relating oil concentrations to specific pollution events. We detected petroleum biomarkers in several coral annual bands related to the major pollution events. However, the oil remaining in these cores has been altered over time and the biomarker ratios found in these oil residues differed from Gulf crude oils. The concentrations of hydrocarbons were compared with the growth parameters of the coral cores. Only one sample may have recorded an “impact” of oil exposure. There was no other correspondence between slight changes in growth parameters between years and the trace chemistry. Therefore, chemical analysis enabled detection of the exposure incident, but provided no insight into the amount of oil to which the coral had been exposed. The chemical data can only infer biological impact if growth was significantly decreased. The average coral growth characteristics of Porites from the four sites in the Arabian Gulf were normal, as predicted from the average water temperatures of the region. There was an indication of an overall decline in growth over time, which should be monitored in the future.

Census of coral reef ecosystems

Three oceanographic institutions are collaborating to conduct a global census of coral reef ecosystems in order to evaluate species abundances and their vulnerabilities to human stressors, the groups announced on 23 JanuaryThis project, called CReefs, is managed by the Scripps Institution of Oceanography, the Australian Institute of Marine Science, and the Pacific Islands Fisheries Science Center of the U.S. National Oceanic and Atmospheric Administration.

Environmental induction of CYP1A-, CYP2M1- and CYP2K1-like proteins in tropical fish species by produced formation water on the northwest shelf of Australia

Normal operation of oil well platforms results in the discharge of "produced formation water" (PFW). The expression of CYP1A, CYP2M1- and 2K1-like proteins was examined for use as possible biomarkers of PFW exposure. A pilot study at the Harriet A production platform, on the Northwest Shelf of Australia, had indicated that PFW contamination possibly contributes to induction of CYP1A- and 2K1/2M1-like proteins in Gold-Spotted Trevally (Carangoides fulvoguttatus). In a subsequent caged fish study in the same location, Stripey seaperch (Lutjanus carponotatus) were caught at a clean site, then distributed to three caging sites: A (near-field), B (far-field) and C (a non-impacted reference site). Fish were sampled at time T = 0, 3 and 10 days. Significant increases of CYP1A, one CYP2K1- and two CYP2M1-like proteins were noted at Site A at T = 10. For another CYP2K1-like protein, a significant increase was observed at Site A only at T = 3. Prevailing winds changed between days 6 and 8 of sampling, moving the surface water plume directly west, possibly impacting in situ PFW exposure. The results indicate that tropical fish CYP1A protein is sensitive to PFW exposure. Importantly, statistically significant environmental induction of both CYP2M1- and CYP2K1-like proteins in tropical fish due to PFW exposure had not previously been described and CYP2 family induction may represent possible new biomarkers (other than CYP1A) of PFW exposure. In addition, the novel fraction-specific response of CYP2K-like proteins requires further verification but offers promise for improved monitoring of sub-lethal responses in marine organisms. (Supported by Australian Institute of Marine Science, Apache Energy Ltd. and the Environmental Toxicology Research Program at The University of Mississippi).

The pearl oysters, Pinctada maxima and P. margaritifera, respond in different ways to culture in dissimilar environments

Growth, Condition Index (CI) and survival of the pearl oysters, Pinctada maxima and P. margaritifera, were measured in three size groups of oysters over 14 months at two dissimilar environments in the Great Barrier Reef lagoon. These were the Australian Institute of Marine Science (AIMS) in a mainland bay and Orpheus Island Research Station (OIRS) in coral reef waters. Temperature, suspended particulate matter (SPM) and particulate organic matter (POM) were monitored during the study. Temperature at AIMS fluctuated more widely than at OIRS both daily and seasonally, with annual ranges 20–31 °C and 22–30 °C, respectively. Mean SPM concentration at AIMS (11.1 mg l − 1) was much higher than at OIRS (1.4 mg l − 1) and fluctuated widely (2–60 mg l − 1). Mean POM level was also substantially higher at AIMS, being 2.1 mg l − 1 compared with 0.56 mg l − 1 at OIRS. Von Bertalanffy growth curve analyses showed that P. maxima grew more rapidly and to larger sizes than P. margaritifera at both sites. For the shell height (SH) of P. maxima, growth index ϕ′ = 4.31 and 4.24, asymptotic size SH ∞ = 229 and 205 mm, and time to reach 120 mm SH ( T (120)) = 1.9 and 2.1 years at AIMS and OIRS, respectively. While for P. margaritifera, ϕ′ = 4.00 and 4.15, SH ∞ = 136 and 157 mm, and T (120) = 2.5 and 3.9 years at AIMS and OIRS, respectively. P. maxima had significantly lower growth rates and lower survival of small oysters during winter compared with summer. There were, however, no significant differences between the two sites in growth rates of P. maxima and final CI values. In contrast, P. margaritifera showed significant differences between sites and not seasons, with lower growth rates, survival of small oysters, final CI values and asymptotic sizes at AIMS. The winter low temperatures, but not high SPM at AIMS, adversely affected P. maxima. Conversely, the high SPM levels at AIMS, but not temperature, adversely affected P. margaritifera. This was in accordance with earlier laboratory-based energetics studies of the effects of temperature and SPM on these two species. P. maxima has potential to be commercially cultured in ca. > 25 °C waters with a wide range of SPM levels, including oligotrophic coral reef waters with appropriate particle sizes. It is possible to culture P. margaritifera in turbid conditions, but its poor performance in these conditions makes commercial culture unlikely.

Summary results from a pilot study conducted around an oil production platform on the Northwest Shelf of Australia

The Australian Institute of Marine Science (AIMS) conducted a pilot study around the Harriet A oil production platform on the Northwest Shelf of Australia. We evaluated hepatic ethoxyresorufin- O-deethylase (EROD) activity, fluorescent aromatic compounds (FACs) in bile and immunodetection of CYP1A-like proteins in two Australian tropical fish species, Gold-Spotted Trevally ( Carangoides fulvoguttatus) and Bar-Cheeked Coral Trout ( Plectropomus maculatus) to assess exposure to petroleum hydrocarbons associated with produced formation water (PFW). Additionally, the incidence of hydrocarbon-degrading bacteria isolated from the liver and bile of all fish captured was examined. Low EROD activity was found in both species, with EROD activity in C. fulvoguttatus showing significant site differences. FACs and CYP1A protein levels in C. fulvoguttatus showed a clear trend in hydrocarbon exposure consistent with hydrocarbon chemistry data: Harriet A > Harriet C > reference site. P. maculatus showed elevated levels of FACs at Harriet A as compared to the reference site and demonstrated detectable levels of CYP1A-like proteins at these two sites. Hydrocarbon-degrading bacteria were found in the liver and bile of both species, yet there was no correlation by sites. Our results demonstrate that C. fulvoguttatus and P. maculatus have potential as indicator species for assessing the effects from exposure to petroleum hydrocarbons. Both FACs and CYP1A are providing warning signs that there is potential for biological effects on fish populations exposed to PFW around the Harriet A production platform.

New studies raise global warming fears

Gradual increases in global temperature may not lead to gradual changes in climate. Nigel Williams reports on new studies that suggest previous climate changes could have been more dramatic and polar environments may be particularly at risk.

Coral recovery at Aldabra Atoll, Seychelles: five years after the 1998 bleaching event

Changes in reef benthos were assessed at Aldabra Atoll following the mass coral bleaching event of 1998. Video transects were used to survey the benthos and analysed using the Australian Institute of Marine Science five-dot method. Comparison of coral cover data collected by the Cambridge Southern Seychelles Atoll Research Programme with data collected during this study revealed that mortality of coral at Aldabra following the bleaching event was approximately 66% at 10 m depth and 38% at 20 m depth. Five years on, there are signs of hard coral recovery at some locations, but in spite of several years of high coral recruitment (7-9 recruits per m2 at 10 m depth, 4-6 recruits per m2 at 20 m depth, where recruits are defined as any colony under 5 cm maximum diameter), recovery of hard coral has not occurred at a significant level. There has been a considerable increase in soft coral cover at some locations, which was dominated by the genus Rhytisma. Macro algal cover did not increase following the bleaching event, although, as would be expected, dead corals have been colonized by coralline algae. There have been no further events leading to large-scale coral mortality at Aldabra since 1998.