Status of

Caribbean

Coral Reefs

after

Bleaching

and

Hurricanes

in 2005

Edited by Clive Wilkinson

and David Souter
Status of

Caribbean

Coral Reefs

after

Bleaching

and

Hurricanes

in 2005

Edited by Clive Wilkinson

and David Souter
ii

Dedication: This book is dedicated to the many people who have worked on coral reefs to understand them and 

ensure that they exist for future generations. One of these deserves special mention; Len Muscatine retired from 

UCLA to his vineyard but did not have enough time to enjoy the fruit of his vines. We miss him. The book is also 

recognises the International Coral Reef Initiative and partners, and particularly those people in the USA, operating 

through the US Coral Reef Task Force, the US Department of State and the US National Oceanic and Atmospheric 

Administration, who continue to strive for greater recognition of the problems facing coral reefs and the need for 

urgent conservation efforts. 

Note: The conclusions and recommendations of this book are solely the opinions of the authors and contributors and 

do not constitute a statement of policy, decision, or position on behalf of the participating organizations.

Front Cover: A stylized map of the maximum Degree Heating Week values observed across the Caribbean during 

2005, indicating the highest level of accumulated thermal stress at each location (image from US National Oceanic 

and Atmospheric Administration Coral Reef Watch).

Inside Title Page: This image shows the 2005 maximum Degree Heating Week data used to create the image on the 

front cover, showing the maximum level of accumulated thermal stress at each location (explained on pages 38 and 

39; image from US National Oceanic and Atmospheric Administration Coral Reef Watch).

Back Cover: A NOAA/Biogeography Branch diver with a 1 metre by 1 metre quadrat examining a bleached 

Montastraea colony at St Croix, US Virgin Islands (photo from NOAA Center for Coastal Monitoring and Assessment 

Biogeography Branch).

Maps were provided by UNEP-WCMC through ReefBase, The WorldFish Center; we thank them. 

Citation: Wilkinson, C., Souter, D. (2008). Status of Caribbean coral reefs after bleaching and hurricanes in 2005. 

Global Coral Reef Monitoring Network, and Reef and Rainforest Research Centre, Townsville, 152 p.

© Global Coral Reef Monitoring Network

c/o Reef and Rainforest Research Centre, 

PO Box 772

Townsville, 4810 Australia

Telephone: +61 7 47212699; 

Facsimile: +61 7 47722808

www.gcrmn.org

ISSN 1447 6185 
iii

Contents

Acknowledgements iv

Foreword 1 

Executive Summary 3

1. Introduction 15

2. Coral Reefs and Climate Change: Susceptibility and Consequences 19

3. Hurricanes and their effects on Coral Reefs 31 

4. The 2005 Bleaching event: Coral-list Log 37

5. Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event 45

6. Coral Reefs of the U.S. Caribbean

 The History of Massive Coral Bleaching and other Perturbations 

 in the Florida Keys 61

 Coral Bleaching in the U.S. Virgin Islands in 2005 and 2006 68

7. The Effects of Coral Bleaching in the Northern Caribbean 

 and Western Atlantic 73

8. Status of Coral Reefs of the Lesser Antilles after the 2005 

 Coral Bleaching Event 85

9. The Effects of Coral Bleaching in Southern Tropical America: 

 Brazil, Colombia, and Venezuela 105

10. Managing for Mass Coral Bleaching Strategies for Supporting 

 Socio-ecological Resilience 115

11. Predictions for the Future of the Caribbean 129

12. Sponsoring Organisations, Coral Reef Programs and Monitoring Networks 135

13. Suggested Reading 145

14. List of Acronyms 148 
iv

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Acknowledgements, Co-sponsors and Supporters of GCRMN

Much of the material for this book was provided voluntarily by more than 70 contributors; we wish to specifically thank 

them for their efforts and dedication towards conserving coral reefs. Many scientific papers and reports were consulted to 

extract data and information; unfortunately we are unable to include all of these, but have added a number of references in each 

chapter and at the back as Suggested Reading. We apologise if pertinent material has not been cited. This report will be lodged 

on ReefBase, at WorldFish Center, which acts as the global coral reef database, www.reefbase.org. Many colleagues assisted us as 

reviewers of text; we wish to thank these people for their time, effort and patience: Robert Buddemeier, Greg Connor, Christine 

Dawson, Carlos Drews, Simon Donner, Scot Frew, Robert Ginsburg, Stefan Hain, Marea Hatziolos, Jim Hendee, Scott Heron, 

Gregor Hodgson, Ove Hoegh-Guldberg, Maria Hood, Christy Loper, Derek Manzello, Peter Mumby, Bernard Salvat, Kristian 

Teleki, Alessandra Vanzella-Khouri and Christian Wild. We specifically thank Fiona Alongi and Tim Harvey for formatting and 

editing; others also assisted us in unseen ways – thanks.

Three operational partners of the GCRMN have assisted with this report: Gregor Hodgson and Cori Kane of the Reef Check 

Foundation; Jamie Oliver, Stanley Tan and Moi Khim Tan of ReefBase; Christy Loper of NOAA who coordinates the Socioeconomic 

Monitoring Network; and colleagues. The Management Group of the GCRMN has provided substantial assistance, advice and 

support: The Intergovernmental Oceanographic Commission of UNESCO; the United Nations Environment Programme Coral 

Reef Unit (UNEP-CRU); IUCN - The World Conservation Union; the World Bank; the Convention on Biological Diversity; 

WorldFish Center; and the ICRI Secretariat, held by Mexico and USA. These meet voluntarily to provide guidance to the GCRMN. 

Direction for the GCRMN Management Group has been provided Carl Gustaf Lundin (Chair), and the GCRMN Chair of the 

Scientific and Technical Advisory Committee, Bernard Salvat, assisted with manuscripts and advice on the format and structure 

of the report - we thank them all. The host of the GCRMN, the Reef and Rainforest Research Centre is specifically thanked.

Support for the GCRMN primarily comes from the US Department of State and the National Oceanic and Atmospheric 

Administration via funds channelled through UNEP in Cambridge, The Hague and Nairobi. This support is critical for the 

operation of the GCRMN and the publication of this Caribbean status report; thus special thanks go to those people involved. We 

received funds to produce, print and distribute this book from: the Government of the USA (Department of State and NOAA); 

IUCN - The World Conservation Union; the United Nations Environment Programme (UNEP); WWF International, especially the 

offices in Europe; the Intergovernmental Oceanographic Commission of UNESCO; Reef Check and the PADI Foundation; RRRCReef and Rainforest Research Centre; ICRAN and the Buccoo Reef Trust. Their assistance ensures that the book will be produced 

and provided free of charge to people around the world who are working to conserve coral reefs, often voluntarily. 

GCRMN Management Group 

IOC-UNESCO –Intergovernmental Oceanographic Commission of UNESCO

UNEP – United Nations Environment Programme

IUCN – The World Conservation Union (Chair)

The World Bank, Environment Department

CBD – Convention on Biological Diversity

AIMS – Australian Institute of Marine Science

GBRMPA – Great Barrier Reef Marine Park Authority

RRRC – Reef and Rainforest Research Centre (host)

WorldFish Center and ReefBase

ICRI Secretariat – Governments of USA and Mexico

GCRMN Scientific and Technical Advisory Committee. 

GCRMN Operational Partners

Reef Check Foundation, Los Angeles

ReefBase, WorldFish Center, Penang

CORDIO – Coral Reef Degradation in the Indian Ocean

World Resources Institute, Washington DC

NOAA – Socioeconomic Assessment group, Silver Springs. 

Major Financial Supporters* and other Supporters of this report 

* The Government of the USA, through the US Department of State, and 

* NOAA – National Oceanic and Atmospheric Administration

* UNEP – United Nations Environment Programme via USA counterpart funds

ICRAN International Coral Reef Action Network (ICRAN) and Buccoo Reef Trust Tobago

IOC-UNESCO - Intergovernmental Oceanographic Commission of UNESCO

IUCN – the World Conservation Union, Gland Switzerland

PADI Foundation and Reef Check, Los Angeles, USA

WWF – Europe
1

Foreword

Here in 2008, we are in the midst of the International Year of the Reef as designated by the 

International Coral Reef Initiative (ICRI). This year-long campaign of events and initiatives is 

aimed at promoting conservation action and building long-term partnerships for sustaining 

coral reef systems. 

1992 was also a critical year for the world’s environment. World leaders met in Rio de Janeiro 

at the United Nations Conference on Environment and Development (UNCED) to sign the 

Convention on Biological Diversity and also pledge major resources for environmental action. 

The Rio Conference also led to negotiations that transformed the Global Environment Facility 

(GEF) from a pilot program to a permanent financial mechanism in support of the global 

environment. Estimates were also made in 1992 that the world had already lost 10% of the coral 

reefs and that a further 60% were under threat of destruction if urgent actions to implement 

sustainable use and conservation of the reefs were not implemented. In the 16 years since 

these estimates were made at the 7th International Coral Reef Symposium in Guam, alarming 

increases in degradation of coral reefs have been reported.

The events of 1992 catalyzed the formation of the ICRI as well as the Global Coral Reef Monitoring 

Network (GCRMN), which has supported production of this book. Chapter 17 of Agenda 21 

that was agreed at UNCED highlighted that coral reefs warranted special attention. This was 

re-affirmed at the World Summit on Sustainable Development in 2002 in Johannesburg, which 

also provided an incentive for countries to work with the GEF to conserve valuable marine 

resources. The Johannesburg Summit urged that small countries be given additional assistance 

to: adopt integrated approaches for watershed, coastal and marine management; recognise 

traditional knowledge and management methods; increase the involvement of communities 

and the private sector in managing coral reefs; improve their capacity to monitor, conserve and 

sustainably manage coral reefs and associated ecosystems; and create representative networks 

of marine protected areas for the conservation and management of coral reefs, mangrove 

forests and seagrass areas.

The GEF attaches critical importance to the health of coral reefs as nearly 500 million people 

across the world depend on them for food, coastal protection, livelihoods, and tourism income. 

This includes about 30 million particularly poor people who depend almost entirely on coral 

reefs for food and protection. The agenda for coral reef conservation in 1992 focused on 

managing the impacts of coastal communities through a new focus on sustainable development 

of these resources. Management efforts were aimed at reducing the impacts from the land of 

excess sediment flows from poor land use, nutrient pollution from human, agricultural and 

industrial wastes, as well as over-exploitation and damaging fishing practices, and damaging 

modification of shorelines. 
2

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

`But that agenda changed after 1998 during the large El Niño and La Niña shift in the global 

climate that resulted in massive coral bleaching. Approximately 16% of the world’s coral reefs 

died in 1998 with especially severe damage in the Indian Ocean and Western Pacific. All of us 

involved in conservation had to focus on the emerging and increasing threat that global climate 

change brings to coral reefs with stressful temperatures, rising sea levels, and threatening the 

ability of corals to survive in potentially more acidic waters. 

Another significant event related to coral reefs occurred in 2005. This book, Status of Caribbean 

Coral Reefs after Bleaching and Hurricanes in 2005, documents the devastating effects on 

coral reefs from the hottest year on record with its very high sea surface temperatures and 

record hurricane activity throughout the Caribbean and Atlantic basins. The development of 

this report has brought together 71 coral reef scientists and managers, predominantly from 

developing countries, to catalogue the impacts of the warming and storms during 2005 and 

subsequently in 2006. 

This detailed information is valuable for environmental managers and supporting agencies to 

underscore urgent actions needed to assist reefs in recovery by focusing on natural resistance 

and resilience as well as removing threats posed by human activities that slow or even prevent 

recovery from these damaging events. More importantly, these findings are particularly critical 

for the peoples of the Caribbean who are highly dependent on these coral reef resources for 

providing natural defences in terms of coastal protection against storms and a buffer against 

sea level rise. Healthy coral reefs also continue to provide food and family income, including 

tropical tourism. 

Last year, the GEF launched a series of new programmatic approaches to support many of the 

Small Island Developing States (SIDS). I had the privilege with Heads of State and top government 

officials from Pacific Island Countries to announce a new type of GEF programmatic approach 

toward sustainable development of islands. Known as the Pacific Alliance for Sustainability, 

the program supports a number of linked GEF operations addressing biological diversity, 

climate change mitigation and adaptation, and integrated approaches toward land and water 

resources management. This new approach comes on the heels of successful GEF projects 

for the Caribbean such as the Mesoamerican Barrier Reef System Project and the landmark 

GEF Coral Reef Targeted Research and Capacity Building project that is working through a 

Center of Excellence in Mexico and others globally in developing countries to find solutions to 

improve coral reef management to sustain these valuable ecosystems.

Throughout the years I have developed a deep appreciation of the traditions and the reliance of 

island communities on the coral reefs and lagoons. For those who also have interest in these 

critically important systems, I recommend this report on the Status of Caribbean Coral Reefs 

after Bleaching and Hurricanes in 2005 and ask you to join the global effort to conserve our 

planet’s coral reef systems.

Monique Barbut

Chair and Chief Executive Officer 

Global Environment Facility
Executive Summary

Clive Wilkinson and David Souter

3

2005 – a hot year

zx 2005 was the hottest year in the Northern Hemisphere on average since the advent 

of reliable records in 1880.

zx That year exceeded the previous 9 record years, which have all been within the last 

15 years.

zx 2005 also exceeded 1998 which previously held the record as the hottest year; there 

were massive coral losses throughout the world in 1998. 

zx Large areas of particularly warm surface waters developed in the Caribbean and 

Tropical Atlantic during 2005. These were clearly visible in satellite images as 

HotSpots.

zx The first HotSpot signs appeared in May, 2005 and rapidly expanded to cover the 

northern Caribbean, Gulf of Mexico and the mid-Atlantic by August. 

zx The HotSpots continued to expand and intensify until October, after which winter 

conditions cooled the waters to near normal in November and December.

zx The excessive warm water resulted in large-scale temperature stress to Caribbean 

corals.

2005 – a hurricane year

zx The 2005 hurricane year broke all records with 26 named storms, including 13 

hurricanes. 

zx In July, the unusually strong Hurricane Dennis struck Grenada, Cuba and Florida.

zx Hurricane Emily was even stronger, setting a record as the strongest hurricane to 

strike the Caribbean before August.

zx Hurricane Katrina in August was the most devastating storm to hit the USA. 

It caused massive damage around New Orleans. 
4

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

zx Hurricane Rita, a Category 5 storm, passed through the Gulf of Mexico to strike 

Texas and Louisiana in September.

zx Hurricane Wilma in October was the strongest Atlantic hurricane on record and 

caused massive damage in Mexico, especially around Cozumel in Mexico. 

zx The hurricane season ended in December when tropical storm Zeta formed and 

petered out in January. 

zx Many of these hurricanes caused considerable damage to the reefs via wave action 

and runoff of muddy, polluted freshwater.

zx The effects were not all bad. Some hurricanes reduced thermal stress by mixing 

deeper cooler waters into surface waters. 

zx Although there were many hurricanes, none passed through the Lesser Antilles to 

cool the waters, where the largest HotSpot persisted. 

2005 – a massive coral bleaching event

zx The warm water temperatures caused large-scale coral bleaching as a stress response 

to the excessive temperatures.

zx Bleached corals were effectively starving and susceptible to other stresses including 

diseases; many died as a result.

zx The first coral bleaching was reported from Brazil in the Southern Hemisphere; but 

it was minor.

zx The first bleaching reports in the Caribbean were in June from Colombia in the 

south and Puerto Rico in the north.

zx By July, bleaching reports came in from Belize, Mexico and the U.S. Virgin Islands 

affecting between 25% and 45% of coral colonies.

zx By August, the bleaching extended to Florida, Puerto Rico, the Cayman Islands, the 

northern Dutch Antilles (St. Maarten, Saba, St. Eustatius), the French West Indies 

(Guadeloupe, Martinique, St. Barthelemy), Barbados and the north coasts of Jamaica 

and Cuba.

zx Bleaching in these countries was generally severe affecting 50% to 95% of coral 

colonies.

zx In some countries (e.g. Cayman Islands) it was the worst bleaching ever seen.

zx By September, bleaching affected the south coast of Jamaica and the Dominican 

Republic, with 68% of corals affected;

zx By October, Trinidad and Tobago was reporting 85% bleaching, and the development 

of a second HotSpot was causing the most severe bleaching for the last 25 years; 

some places reported 100%, although it was highly variable between sites;

zx By November, minor bleaching also affected Venezuela, Guatemala and the Dutch 

islands of Bonaire and Curacao, affecting 14% to 25% of corals.

zx In many countries (Cuba, Jamaica, Colombia, Florida, USA) there was great variation 

in bleaching between sites. In Florida, areas exposed to regular large temperature 

fluctuations, and nutrient and sediment loads were less affected. In the French West 

Indies, the variation was attributed to different species composition between sites.
5

Executive Summary

zx The corals vulnerable to bleaching were similar across the Caribbean, particularly: 

Acropora palmata and A. cervicornis, Agaricia, Montastraea, Colpophyllia, Diploria, 

Siderastrea, Porites, the hydrozoan Palythoa and the hydrocoral Millepora, which 

has nearly disappeared from the French West Indies.

zx Bleaching persisted to mid-2006 in Guadeloupe, Martinique, Barbados and Trinidad 

and Tobago, and, in 2007 in St. Barthelemy. Reefs in these countries showed few 

signs of recovery, with between 14% and 33% of colonies still bleached.

2005 – extensive coral mortality and disease

zx The greatest damage occurred in the islands of the Lesser and Greater Antilles where 

corals were bathed in abnormally warm waters for 4 to 6 months. 

zx The greatest coral mortality occurred in the U.S. Virgin Islands, which suffered an 

average decline of 51.5% due to bleaching and subsequent disease; the worst seen in 

more than 40 years of observations.

zx Barbados experienced the most severe bleaching event ever with 17% to 20% coral 

mortality.

zx Losses in the French West Indies ranged between 11% and 30%.

zx In the northern Dutch Antilles, there was 18% mortality in St. Eustatius, but 

minimal mortality in Bonaire and Curacao in the south. 

zx Trinidad and Tobago suffered considerable mortality, with 73% of all Colpophyllia 

and Diploria colonies dying.

zx Although there was severe bleaching in the Greater Antilles, minimal mortality 

occurred in Bahamas, Bermuda, Cayman Islands, Cuba, Jamaica and Turks and Caicos; 

some sites in the Dominican Republic, however, suffered up to 38% mortality.

zx Bleaching mortality was minimal on the Mesoamerican Reef system, largely because 

many storms cooled sea temperatures; however, Hurricanes Emily and Wilma 

damaged some reefs, decreasing coral cover from 24% to 10%, especially around 

Cozumel.

zx Coral mortality in Colombia and Venezuela was negligible.

zx Increased prevalence of disease following bleaching was reported from many islands 

of the Lesser Antilles, particularly French West Indies; infection rates increased from 

33% to 39% on Guadeloupe and 18% to 23% on St. Barthelemy; 49% of corals were 

infected on Martinique.

zx In Trinidad and Tobago, there was clear evidence of an increase in the prevalence of 

disease.

zx In the U.S. Virgin Islands, secondary disease infections killed bleached colonies of 

Montastraea, Colpophyllia, Diploria and Porites.

2005 – lessons for management and future options

zx Unfortunately direct management action is unlikely to prevent coral bleaching and 

mortality from climate change on most of the world’s reefs.

zx However, effective management can reduce the damage from direct human pressures 

and encourage the natural adaptation mechanisms to build up reef resilience; 
6

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

zx Such actions will promote more rapid recovery in the future, especially if bleaching 

will become a regular event.

zx Unfortunately, current predictions are for more frequent and intense warming in the 

Caribbean with the high probability of increased bleaching and coral mortality.

zx Severe coral bleaching is predicted to become a more regular event by 2030, and an 

annual event by 2100, if the current rate of greenhouse emissions is not reversed. 

Introduction

The most extreme coral bleaching and mortality event to hit the Wider Caribbean (including 

Atlantic) coral reefs occurred in 2005. This was during the warmest year ever recorded, eclipsing 

the 9 warmest years that had occurred since 1995. The previous warmest year was 1998, 

which resulted in massive coral bleaching throughout many parts of the world and effectively 

destroyed 16% of the world’s coral reefs, especially in the Indian Ocean and Western Pacific. 

Unlike the events of 1998, this climate-related bleaching event did not occur in an information 

vacuum; this time there were many scientific tools available and alerts issued to those 

working and managing coral reefs in the Caribbean to assess the damage and possibly prepare 

management responses to reduce the damage. This book explains coral bleaching and follows 

the sequence of the events leading up to it, and documents much of the damage that occurred 

to the coral reefs and consequently to the people dependent on coral reefs for their livelihoods 

in the Wider Caribbean. 

This graph from the Hadley Climate Center in the UK shows that surface temperatures in the Northern 

Hemisphere have been much higher in the last two decades and appear to be increasing from the 

baseline of temperatures in 1960. The red line is a 10 year running average.
7

Executive Summary

It May 2005, analysis of satellite images by the National Oceanic and Atmospheric Administration 

(NOAA) of USA showed that the waters of the Southern Caribbean were warming faster than 

normal and people in the region were asked to look out for coral bleaching. The warming 

was evident as a ‘HotSpot’ of warmer water which was likely to stress corals in the Northern 

Caribbean (see p. 38). 

As the surface waters continued to heat up, it became obvious that this was going to be a 

particularly stressful year for the coral reefs of the Caribbean. NOAA issued a regular series of 

information bulletins, warnings and alerts on the warming waters and developing hurricanes, 

thereby stimulating coral reef managers and scientists to examine their coral reefs for signs 

of bleaching. Throughout August, September and October it became clear in reports from the 

Wider Caribbean that 2005 was probably the most severe coral bleaching and mortality event 

ever recorded. The HotSpot warming reached its peak in October and then dissipated as winter 

approached and solar heating shifted to the southern hemisphere. However, monitoring of 

the corals continued into 2006 to assess either recovery from bleaching, or incidences of coral 

disease or mortality. There were also preliminary assessments of the social and economic costs 

of this HotSpot phenomenon. 

The 2005 bleaching event has followed a long, slow decline in the status of Caribbean coral reefs 

over thousands of years; especially during the last 50 years. Many Caribbean reefs have lost up 

to 80% of their coral cover during this time. The causes included climate related factors prior 

to 2005, but most of the coral losses were due to direct human impacts such as over-fishing, 

excess sediment input, increases in nutrients from agriculture and domestic sewage, and 

direct damage to reefs during development. These impacts are all symptomatic of increasing 

human populations and their use of the reefs, such that many of these occur simultaneously. 

The damage symptoms are often seen as particularly low fish populations, outbreaks of coral 

diseases, or corals struggling to grow in poor quality, dirty waters or smothered by algae. Thus 

many of the reefs of the Wider Caribbean were already stressed and in decline when the major 

climate change events of 2005 struck.

The islands and mainland countries of the Caribbean are highly dependent on coral reef 

resources, thus there is an urgent need for appropriate management responses as sea 

temperatures are predicted to increase further in future. The World Resources Institute Reefs@

Risk analysis estimated that Caribbean coral reefs in 2000 provided between US$3,100 million 

to $4,600 million each year from fisheries, dive tourism, and shoreline protection services; 

however 64% of these same reefs were threatened by human activities, especially in the Eastern 

Caribbean, most of the Southern Caribbean, Greater Antilles, Florida Keys, Yucatan, and the 

nearshore parts of the Mesoamerican Barrier Reef System. All these areas suffered severe 

bleaching damage in 2005. The R@R analysis indicated that coral loss could cost the region 

US$140 million to $420 million annually.

This book compiles data and observations of coral bleaching and mortality from more than 

70 coral reef workers and volunteer divers to summarize the current status of reefs in the 

Wider Caribbean; but more importantly the book seeks to provide information to coral reef 

managers and decision makers to aid in the search for solutions to arrest the coral reef decline 

in a region that contains 10.3% of the world’s reefs. These compiled reports also illustrate the 

value of early predictions of possible bleaching; ‘products’ developed by NOAA from archived 
8

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

and current satellite images, complemented by direct measures like temperature loggers and 

buoys, were used to warn of the impending bleaching threat. The products were distributed 

widely through e-mail alerts and various internet sites, alerting natural resource managers of 

the potential for damage to their coral reefs. Hundreds of scientists and resource managers in 

the Caribbean used these alerts and products in 2005 to allocate large amounts of their limited 

financial and logistic resources to monitor what turned out to be a record-breaking bleaching 

event. The information yielded from this monitoring will be vital to future management efforts 

to protect coral reefs in light of today’s rapidly changing climate. 

The 2005 Coral Bleaching Event and Hurricanes

These following HotSpot images and the other ‘Degree Heating Week’ images on the front cover 

and inside title page are typical of the information that was widely dispersed throughout the 

Caribbean and elsewhere via the Internet through the coral reef information network ‘CoralList’. This generated considerable correspondence, and senior NOAA scientists have offered 

their personal insight of what happened in their offices as the sequence of events developed. 

These are detailed in Chapter 4. 

This 1st figure illustrates a typical HotSpot image (explanation on p. 38) that was generated from 

satellite data and distributed throughout the Wider Caribbean. The HotSpot on 16 July 2005 shows 

waters 1oC to 2oC above the normal summer maximum as seen as ‘warm’ yellow and orange colors 

over central America as well as a large but less warm region in the central Atlantic Ocean; as this was 

being reported there was evidence of bleaching reported in Belize. 

The first signs of bleaching were in Brazil in March during the southern summer. However, 

this did not correspond to a major HotSpot; it was more likely due to a local calm weather and 

heating event. The first coral bleaching in the Caribbean was reported in early June on the 

Islas del Rosario in northwest Colombia where waters had warmed to 30oC. These waters then 

cooled and the corals recovered. By late June, surface waters exceeded 30oC around Puerto 
9

Executive Summary

Rico, and up to 50% of corals had already died. There was also bleaching on the Caribbean coast 

of Panama, although this did not result in significant mortality. 

In July, bleaching was reported in Belize, Mexico, Bahamas and in Bermuda and the US Virgin 

Islands, which also coincided with reports of the death of large sponges in the US Virgin Islands 

and off Cozumel in Mexico. 

Although between 25% and 45% bleaching was reported in Belize and Mexico, the HotSpot 

along the Mesoamerican Reef system dissipated with the regular passage of storms during 2005, 

which prevented any significant bleaching related mortality. Despite the cooling benefits to the 

region, Hurricanes Wilma and Emily caused considerable damage to coral reefs, especially 

in Mexico around the island of Cozumel. Lower mortality in the Mesoamerican region may 

be attributable to a reduced population of temperature sensitive corals, because previous 

bleaching and disease events have removed the more sensitive species. It appears that the more 

resistant species were only slightly affected. Coral cover has decreased markedly in the past 35 

years, in some cases from near 80% to less than 20%. 

This image from mid-August shows a dramatic expansion of two HotSpots with temperatures 2oC 

to 3oC in excess of the summer maximum covering large parts of the Northern Caribbean including 

Florida, the Flower Garden Banks in the Gulf of Mexico and just touching Cuba. The HotSpot in the 

Atlantic has expanded alarmingly to cover all the islands of the Lesser Antilles; and there is a small 

HotSpot over Colombia. Bleaching was being reported in all of these regions, as outlined in the 

following chapters.

By early August, concern was growing that bleaching would damage the reefs of Florida and 

the Gulf of Mexico. As the HotSpot expanded in the north, there were reports of extensive 

bleaching in the Florida Keys, with water temperatures around 31°C and almost totally calm 

and sunny conditions. In late August, extensive bleaching coincided with the warmest water 
10

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

ever recorded on Sombrero Key in Florida, but fortunately for these reefs, Hurricane Katrina 

passed through the area as Category 1 storm resulting in considerable cooling of the waters 

(see p. 35). 

Similarly, bleaching increased around Puerto Rico involving all corals and coral-like animals 

under hot calm conditions and the incidence of coral disease increased alarmingly. Severe 

bleaching, up to 95%, was being reported from several islands in the Greater (Cayman Islands, 

Jamaica, Cuba) and Lesser Antilles (Guadeloupe, Martinique, St. Barthelemy in the French 

West Indies, St. Maarten, Saba, St. Eustatius in the northern Dutch Antilles, and Barbados). 

Bleaching in the Cayman Islands was the worst ever recorded. 

By early September, two major HotSpots with sea surface temperatures 2oC to 3oC more than normal 

are covering Puerto Rico, the Virgin Islands and the other is still covering the Lesser Antilles. The 

original HotSpot over the Gulf of Mexico and Florida has been effectively ‘blown away’ by Hurricanes, 

especially Katrina that went on to devastate New Orleans on 29 August 2005 (see the Chapter on 

Hurricanes p. 31). Reports of major coral bleaching were received corresponding to all the sites with 

HotSpots. 

The weather was particularly calm for two weeks in September, and was accompanied by 

extensive bleaching on the south coast of Jamaica where about 80% of corals bleached. The 

August bleaching on the north coast of Jamaica began to subside. Sea temperatures in the U.S. 

Virgin Islands reached more than 30°C at 16 m depth. Bleaching affected most coral species. 

More than 90% of corals bleached down to 30 m on the nearby British Virgin Islands. More 

extensive bleaching continued on northern Puerto Rico. The bleaching footprint had expanded 

to include Trinidad and Tobago and the Dominican Republic reported bleaching in 85% and 

68% of corals. 
11

Executive Summary

The peak of HotSpot activity occurred in early October with a massive area of warm water covering 

virtually all the central and eastern Caribbean. A series of Hurricanes had helped cool the waters 

of the Northern Caribbean; but there were no hurricanes to pass through the Lesser Antilles where 

the waters were warmest. In mid to late October the HotSpot ‘followed the sun’ southward and then 

bathed the Netherlands Antilles and the northern coast of South America. By early November, the 

HotSpot had virtually dissipated and conditions had returned to normal. However, this 4 month 

period of unusually warm waters had wreaked havoc throughout the Wider Caribbean as is described 

in the following chapters. 

By October, dangerously elevated sea temperatures had been bathing the Lesser Antilles for 

almost 6 months; most of this time the temperatures exceeded the normal coral bleaching 

thresholds. This sustained thermal stress resulted in the most severe coral bleaching and 

mortality ever recorded in the Lesser Antilles with 25% to 52% coral mortality in the French 

West Indies, and the most severe bleaching event ever recorded around Barbados. Bleaching 

affected all coral species at all depths. In the Netherlands Antilles there was 80% coral bleaching 

around the islands to the north, near the British Virgin Islands, whereas around Bonaire and 

Curacao in the south there was only minor bleaching and virtually no mortality. Further to the 

east there was 66 to 80% bleaching of the coral cover on Tobago. On average, the accumulated 

Caribbean thermal stress during the August-November period was greater than had been 

experienced by these reefs during the previous 20 years combined.

A second bout of bleaching started when the HotSpot ‘followed the sun’ with Colombia seriously 

affected in October and the peak bleaching in Venezuela in November and December 2005. 

Bleaching was highly variable with sites reporting anything from zero to 100% bleaching, but 

the mean was closer to 25%; fortunately mortality on reefs in tropical South America was far 

less than on reefs to the north. 
12

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Why Climate Change is a Threat to Coral Reefs

Corals bleach when the coral animal host is stressed and expels the symbiotic zooxanthellae 

(algae) that provide much of the energy for coral growth, and coral reef growth. Although 

several different stresses cause bleaching, by far the most significant cause of coral bleaching 

in the past 25 years has been sea surface temperatures that exceed the normal summer maxima 

by 1 or 2oC for at least 4 weeks. This results in excessive production of toxic compounds in the 

algae that are transferred to the host coral. The host coral reacts by expelling their symbiotic 

algae, leaving the coral ghostly white and particularly susceptible to death from starvation 

or disease. If conditions become more favorable, corals often recover, although they often 

experience reduced growth and may skip reproduction for a season. In 2005, many bleached 

corals did eventually die.

Coral bleaching was first noticed as a significant problem in the wider Caribbean region in 1983. 

Concurrently there were increases in coral disease across the region, thus the assumption was 

made that these were both associated with higher temperatures. The bleaching and outbreaks 

of infectious diseases, such as white plague, have caused such major losses in the branching 

staghorn and elkhorn corals (Acropora cervicornis and A. palmata), that they were added to 

the List of Endangered and Threatened Wildlife under the Endangered Species Act of U.S.A. in 

April 2007. The listing as Threatened Species requires that US government agencies maximize 

their efforts at conserving these species, which are the most characteristic of Caribbean reefs 

and were once major contributors to reef construction. 

The bleaching in 2005 ‘coincided’ with major outbreaks of coral diseases which saw extensive 

shrinkage in the cover of live corals throughout the Caribbean. While many corals started to 

recover when seawater temperatures dropped with the onset of winter, coral diseases broke out 

and resulted in significant losses of coral cover, notably along the coast of Florida (Chapter 6), 

in Belize (Chapter 5), the Virgin Islands (Chapter 7), and the Lesser Antilles (Chapter 8). The 

accepted explanation is that bleached corals are stressed, lack reserve lipid supplies and are 

effectively starving, making them more susceptible to disease.

Ocean acidification is a parallel climate change threat to coral reefs that results from increased 

concentrations of CO2

 dissolving in seawater, which reduces its pH. This process is called ‘ocean 

acidification’, and by the end of this century, acidification may be proceeding at a rate that is 

100 times faster and with a magnitude that is 3 times greater than anything experienced on 

the planet in the last 21 million years. How this will affect marine ecosystems is unknown, but 

impacts on marine calcifiers could be considerable. Using the pH levels expected by the end of 

this century, laboratory studies show a significant reduction in the ability of reef-building corals 

to grown their carbonate skeletons, making them both slower to grow and more vulnerable 

to erosion. This would also affect the basal structure of coral reef itself. While the long term 

consequences of ocean acidification on corals is not known, corals do not seem to be able to 

easily adapt to such rapid changes. All predictions from climate change models point to ocean 

acidification having progressively more negative impacts on corals and coral reefs. 

Hurricanes and extreme weather events are also predicted to become more frequent and severe 

as the pace of climate change quickens. There is increasing evidence that the proportion of 

more destructive hurricanes has increased in recent decades, although the total incidence of 

tropical storms has not increased. Stronger hurricanes will result in more severe wave damage 
13

Executive Summary

and flooding from the land, thereby adding an additional stress to already stressed reefs. Low 

to moderate strength hurricanes can be beneficial during summer, however, by cooling surface 

waters and reducing the likelihood of coral bleaching.

There is insufficient evidence or indications that the other potential climate change stresses 

will result in significant damage to coral reefs. There is a potential for negative impacts from 

possible shifting of ocean currents or rises in UV concentrations; however these are not evident 

at the moment. Sea level rise will not directly threaten corals, but may render coral reef islands 

uninhabitable, thereby threatening coral island cultures and nations. 

Implications of 2005 for Coral Managers

Coral reef managers were unprepared for the climate-related destructive events of 1998. Many 

coral reef managers in the Indian Ocean and Western Pacific reported that massive coral 

bleaching in mid to late 1998 was devastating their coral reefs, and they asked ‘what have I done 

wrong to cause the corals to die’. They were perplexed that corals were dying on the same reefs 

that they were actively managing to remove pollution, sedimentation and over-fishing stresses. 

The cause of the problems to their reefs was related to climate change via a particularly severe 

El Niño and La Niña climate switch that raised sea surface temperatures (SSTs) above levels 

that had ever been recorded on those coral reefs. We now know that no management actions 

could have prevented the extent of coral death; the only advice the coral reef research and 

management community could offer was that ‘better managed reefs will recover more rapidly 

than those under human stresses’.

The events of 1998 stimulated the international coral reef community to develop advice for 

coral reef managers faced with similar circumstances in the future. A Reef Manager’s Guide 

to Coral Bleaching was developed in 2006 to provide that advice for coral reef managers faced 

with stresses beyond their immediate control. The report is summarized by the authors in 

Chapter 10 and provides reef managers with the explanations why reefs are damaged by such 

climate related events and explains why some reefs resist coral bleaching and others are more 

resilient i.e. they recover faster after severe losses. 

The report guides reef managers into steps they can take at national and global levels to raise 

awareness of the potential devastation that increasing global climate change, though the release 

of greenhouse gases, can have on coral reefs. However, the emphasis is on providing managers 

with practical advice on how to increase protection of those reefs that are either naturally 

resistant or tolerant to bleaching, assist in promoting adaptation mechanisms that enhance reef 

resilience, while simultaneously reducing local pressures on the reefs and nearby ecosystems 

to enhance chances for natural recovery. Importantly, the Guide advises reef managers on how 

to engage with local people and assist in maintaining socioeconomic well-being and bringing 

them on board to assist in the sustainable use of their coral reefs.

And the Future

Sadly for coral reefs, all predictions from the Intergovernmental Panel on Climate Change 

(IPCC) reports in 2007 indicate that the extreme warming of 2005 will not be an isolated event 

(Chapter 11). It will probably happen again in the future and, when it does, the impacts will 

be even more severe. The IPCC concluded that human-induced climate change will warm the 
14

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

world by 1.8 to 4.0oC by the year 2100. This warming will affect most of the wider Caribbean 

Sea making years like 2005 more common and more devastating for coral reefs. 

In addition, increasing acidity in the seawater with the solution of more CO2 will result in 

slower growth of corals that are trying to recover from bleaching and other disturbances.

One other potential consequence of the human-induced warming is an increase in the frequency 

of more damaging Category 4 and 5 hurricanes in the Caribbean. These storms develop as 

waters warm over the tropical North Atlantic and Caribbean waters. It is predicted that warmer 

surface waters with increased amounts of thermal energy will fuel increases in tropical storm 

strength. The latest predictions are for an increase in the more intense Category 4 and 5 

hurricanes that will probably cause significant damage to the coral reefs and the communities 

that depend upon them (Chapter 3).

This figure shows the proportion of intense hurricanes has been increasing since 1970 while the 

total number of hurricanes has not changed much. These graphs plot all global hurricanes combined 

into 5 year periods from 1970 to 2004, with projected trends added to 2019. Category 1 storms are 

relatively weak whereas Category 5 storms are particularly devastating (adapted from Webster 2005). 

Dashed lines show significant linear trends.

This is a pivotal moment for the coral reefs. The world is already committed to some further 

warming due to past greenhouse gas emissions and the expected emissions from existing world 

energy infrastructure (Chapter 2). Thanks to more than a century of ‘committed warming’; 

events like 2005 are expected to occur more frequently by the 2030s. The only possible way to 

sustain some live coral on the reefs around the world will be to carefully manage the direct 

pressures like pollution, fishing and damaging coastal developments, and hope that some 

coral species are able to adapt to the warmer environment. However, a dramatic reduction in 

greenhouse gas emissions in the next 20 years will be critical to control further warming and 

higher CO2

 levels that will probably reduce the robustness and competitive fitness of corals and 

limit the habitats for many other organisms living on Caribbean coral reefs.

Category 1

Category 2 & 3

Category 4 & 5

5 – year period

50

20

10

30

40

0

70-74 75-79 80-84 85-89 90-94 95-99 00-04 05-09 10-14 14-19

% Hurricanes per category
15

The crisis facing coral reefs was only fully recognised during the last two decades. Gradual 

and chronic stresses have resulted in major losses of coral reefs in areas surrounding large 

human populations, but the pace of change was slow. Over-fishing and destructive fishing, 

pollution with nutrients and sediments, coral diseases, mining of coral rock and sand, and 

coastal developments that modified the reefs were the predominant chronic stresses damaging 

coral reefs around the word. However, global climate change is now a major threat to the longterm future of the world’s coral reefs.

The major El Niño/La Niña Southern Oscillation (ENSO) cycle in 1997-98 resulted in massive 

losses of corals in the Indian Ocean and the Western Pacific. It was estimated that 16% of the 

world’s coral reefs were effectively destroyed in about 10 months when sea surface temperatures 

increased considerably and killed corals in many areas, including those remote from damaging 

human activities. 

Then 2005 was the hottest year in the world’s recorded history, causing a major bleaching 

event in the Caribbean without a concurrent El Niño. This year surpassed 1998 and the other 

8 hottest years during the past 15 years and further confirms a pattern of global climate 

change. This report documents the effects of raised temperatures in causing coral bleaching 

and mortality in the wider Caribbean in 2005 and whether the stressed corals recovered. The 

report also examines the effects of severe category 4 and 5 hurricanes during 2005 that also 

damaged coral reefs and other coastal ecosystems. Fortuitously, several of these hurricanes 

actually protected some reefs by cooling the waters that were causing heat stress. The damage 

that occurred to reefs in the Caribbean, however, has followed centuries of reef degradation 

from human activities.

Assessment of climate change effects on marine ecosystems requires a focus on physical 

observations as well as examining the organisms in the ecosystem. The National Oceanic and 

Atmospheric Administration (NOAA) of USA is mandated to understand the environment and 

ecosystem within a changing climate, and use this understanding to improve conservation and 

management of living marine resources and ecosystems. Thus, NOAA provides products to alert 

users of the potential for coral bleaching events around the world through satellite and in situ 

observations, forecasts and warning systems. NOAA also works with local and regional managers 

to quantify the effects of increasing seawater temperatures on coral reefs, and determine ways 

local managers can mitigate climate change impacts. A partnership was formed with the Great 

Barrier Reef Marine Park Authority of Australia, the U.S. Environmental Protection Agency, 

and the IUCN (The World Conservation Union) to produce ‘A Reef Manager’s Guide to Coral 

Bleaching’, featured in Chapter 10. NOAA and the Department of Interior led an interagency 

1. Introduction
16

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

effort to respond to and assess the 2005 massive coral bleaching event in the Caribbean under 

the aegis of the U.S. Coral Reef Task Force. The effort also involved many government and 

NGO agencies, including local partners in Florida, Puerto Rico, the U.S. Virgin Islands, and 

Caribbean island nations, to assess the impacts of the 2005 mass bleaching event and make 

recommendations on how to prepare for and address future events.

The marine life and people in the Caribbean depend on healthy coral reef ecosystems and the 

services they provide, especially for tourism, fishing and costal protection. The unprecedented 

and region-wide bleaching event of 2005 has, and will continue to have, far-reaching ecological 

and major economic implications for the region. UNEP, via the UNEP Coral Reef Unit, assists 

partners such as the GCRMN in collecting, assessing and disseminating comprehensive and 

reliable data to decision makers on the status of coral reefs. The Caribbean Environment 

Programme (CEP) of UNEP provides the Secretariat to the Cartagena Convention on the 

protection and development of the marine environment in the Wider Caribbean. UNEP CEP 

works closely with its 36 member governments and other stakeholders to create, harmonize and 

implement policies, regional cooperation and meaningful actions towards the conservation and 

sustainable use of coastal and marine resources in the Caribbean, including coral reefs. Local and 

regional activities are implemented on integrated coastal area management, strengthening of 

Marine Protected Areas, coral reef monitoring, control of land-based pollution, and promotion 

of better-practices for fishers and sustainable tourism. UNEP CEP and the Coral Reef Unit acts 

as the link for these countries into the GCRMN, to assist them in responding to the impacts 

affecting coral reefs, such as those caused by the 2005 bleaching event.

Since 2006, IUCN has hosted the Marine Working Group on Climate Change and Coral Reefs 

(CCCR), a widely representative collaborative initiative established with support from the 

MacArthur Foundation. CCCR provides a mechanism to focus scientific contributions from 

leading research groups, and synthesize the relevance of resilience to coral reefs and climate 

change. It seeks to bridge gaps between theoretical science and management application in 

order to fast-track the development and use of tools to improve the protection of coral reefs 

under the threat of climate change and interacting or synergistic human threats. IUCN also 

works extensively with members and partners on developing and applying better practices for 

ecological adaptation management, including incorporation of best practice climate change 

resilience principles into the design and management of regional Marine Protected Area 

networks and capacity building. 

WWF is a global conservation organisation that views climate change as a significant threat 

to coastal ecosystems and livelihoods, and is working to develop adaptation strategies to build 

ecosystem resilience and improve the ability to cope with a changing climate. Within the 

Mesoamerican Reef Ecoregion, WWF and partners are working to reduce direct human threats 

to reefs (e.g. collaborating with agroindustries and local farmers to reduce agrochemical use and 

working with fishermen on sustainable fishing practices) while concomitantly implementing 

critical steps towards building reef resilience. Through collaboration with partners, WWF 

assessed the Mesoamerican Reef System in 2006 to ascertain overall reef status and promote 

protection of bleaching resilient and resistant reefs. WWF is also working on strategies to 

build social networks for adaptation, including: improved communication, awareness and 

public outreach; climate witnesses (for local and international outreach); training and capacity 

building for WWF staff and local counterparts; and climate change policy recommendations 

(e.g. Government of Belize adaptation strategy) based on local consultation.
17

Introduction

The Intergovernmental Oceanographic Commission (IOC) of UNESCO provides an 

intergovernmental forum to catalyze and coordinate research on coral reef ecosystems. The 

IOC sponsors international science required to answer management questions: the causes of 

coral reef degradation; the global status of coral reef health; the predictions of impacts (both 

ecological and socioeconomic); and actions to minimize impacts or adapt to changes. The 

network of 136 Member States is used to communicate the results of these programs to stimulate 

coordinated action at local, national, and global levels. The IOC sponsors: the Coral Bleaching 

Working Group of the GEF / World Bank Coral Reef Targeted Research and Capacity Building 

Project; the Ocean in a High CO2 World symposium series (assessing current knowledge on 

ocean acidification impacts on marine ecosystems); the Global Coral Reef Monitoring Network; 

and has worked recently with UNEP and the Census of Marine Life to report on the vulnerability 

of deep-sea corals to fishing on seamounts beyond areas of national jurisdiction. They also 

work with other programs within UNESCO dealing with coral reef issues, such as the Coasts 

and Small Islands Program and the World Heritage Center’s Marine Program.

The emergence of climate change was recognised as an over-arching threat to tropical marine 

ecosystems at the 3rd International Tropical Marine Ecosystem Management Symposium 

(ITMEMS) in Mexico, 2006. This meeting was coordinated by the International Coral Reef 

Action Network (ICRAN) to facilitate discussion and information sharing on coral reef resilience 

and management, and particularly to communicate climate related challenges for managers 

(the ICRI statement on climate change is discussed in Chapter 10). ICRAN encourages natural 

resource management to increase the resilience of coral reef ecosystems through effective 

implementation of marine managed areas, and the promotion of networks of managed areas. 

ICRAN is partnering with the World Resources Institute on a global analysis of threats to 

reefs, including vulnerability of coral reefs and associated communities to bleaching, and the 

economic impacts of reef degradation. 

Conservation of coral reefs in the face of increasing global warming will require that all 

relevant people are informed and encouraged to take remedial action. This is why volunteer 

and community based organisations like Reef Check and the PADI Foundation are critical to 

successful action. Reef Check has been working with the GCRMN to monitor coral reefs using 

a standard method since 1997 and now has teams in over 90 countries. The goals include 

tracking the impacts of climate change as well as to conserve remaining coral reefs. This 

important report documents the serious impacts of the 2005 bleaching event in the Caribbean 

and includes data collected by Reef Check teams in collaboration with NOAA. These data reveal 

interesting differences in the effects of a major bleaching event on reefs in the Caribbean 

compared with the Indo-Pacific and provide hope that some reefs may be more resistant than 

others to temperature stress. 

This book collates considerable data and information gathered by NOAA staff, and other coral reef 

researchers and managers in the Caribbean. These reports will help clarify our understanding 

of how global climate change is affecting coral reefs and other tropical coastal ecosystems. 

The final chapter in this book draws on climate change models to attempt predictions in the 

short to medium-term for the wider Caribbean. This report also illustrates the importance of 

supporting the GCRMN and partners in monitoring reefs and preparing plans for a warmer 

world.
18

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

We represent organisations that are working towards the sustainable use and conservation of 

coral reefs around the world, and request that governments, organizations and people actively 

participate in the International Year of the Reef in 2008 to promote education, research 

and public awareness about the value of coral reefs and threats to their health. We, and the 

thousands of people we represent, call on all people to acknowledge that global climate change 

represents a serious and increasing threat to the integrity of the coral reefs of the world, and 

seek mechanisms to ameliorate the effects and reduce future impacts. Thus, we are pleased to 

endorse the GCRMN report ‘Status of Caribbean Coral Reefs after Bleaching and Hurricanes 

in 2005.’ 

David Kennedy, 

CRCP Program Manager, National Oceanic and Atmospheric Administration (NOAA), USA

Nelson Andrade Colmenares, Coordinator

United Nations Environment Programme, Caribbean Environment Programme

Carl Gustaf Lundin, 

Head, Global Marine Programme, IUCN – The World Conservation Union & Chair, GCRMN 

Management Group

Simon Cripps

Director, International Marine Programme, WWF International

Patricio Bernal, 

Executive Secretary, Intergovernmental Oceanographic Commission of UNESCO

Kristian Teleki, Director ICRAN International Coral Reef Action Network

Gregor Hodgson

Executive Director, Reef Check Foundation
19

Summary

zx Coral reefs, both tropical and deep cold water, are global centers of biodiversity that 

are being damaged by a combination of direct human impacts and global climate 

change.

zx The major threats associated with climate change are increasing sea temperatures 

and increasing ocean acidity as a result of rising atmospheric carbon dioxide (CO2), 

as well as a predicted increase in storms.

z Higher than normal sea surface temperatures cause increased stress to corals and 

result in coral bleaching, and frequently in mortality. We have a better understanding 

of why the apparently stable symbiosis between corals and their symbiotic 

dinoflagellate (zooxanthellae) algae breaks down. Bleaching results in the loss of the 

algae and a reduction in the coral’s energy producing systems; severe stress often 

results in coral mortality.

zx Increasing concentrations of CO2 lower the pH of seawater, which reduces the 

capacity of corals and many other marine organisms to make calcium carbonate 

skeletons because of a coincident decrease in the concentration of carbonate ions.

zx These threats acting in combination with local factors, such as declining water 

quality and over-fishing, will reduce the resilience of coral reefs, and change reef 

structure and community composition. The result will reduce biodiversity through 

large-scale loss of functional reef ecosystems and the many other organisms that 

depend on them.

zx Action to conserve these reefs is now urgent and must include global and local 

strategies via the implementation of strong policies for reductions in greenhouse 

gas emissions and effective management of local stresses that are also damaging 

coral reefs.

2. Coral Reefs and Climate Change:

Susceptibility and Consequences

Joan Kleypas and Ove Hoegh-Guldberg
Status of Coral Reefs in the Caribbean after Bleaching and Hurricanes of 2005

20

Introduction

Tropical coral reefs are probably the most sensitive marine ecosystem in the world to global 

climate change. Reefs are already being devastated by the consequences of climate change, 

and will probably suffer particularly serious damage in the next 10 to 20 years. This chapter 

seeks to answer the questions: ‘Why are coral reefs particularly susceptible to global climate 

change?’ and ‘What consequences will flow from this sensitivity to changing environmental 

conditions?’

The following possible impacts on coral reefs will be examined in this Chapter:

1. Rising sea surface temperatures; 

2. Increasing concentrations of CO2

 in seawater; 

3. Sea level rise; 

4. Possible shifting of ocean currents; 

5. Associated rises in UV concentrations; and

6. Hurricanes and cyclonic storms.

This chapter focuses on the tropical shallow water corals that live in symbiosis with dinoflagellate 

algae. However, there are vast areas of deep-sea corals that live at great depths in dark, cold 

waters. These vast and complex ecosystems were largely unknown until very recently, but there 

are serious concerns that global climate change will result in major damage, especially through 

increasing concentrations of CO2 in seawater (see the Box below).

Coral reefs are particularly long-lived and highly evolved ecosystems. Tropical reefs are 

technically shallow water calcium carbonate deposits that arise from the activities of marine 

organisms. They have existed in one form or another for more than 650 million years. The 

major organisms that constructed reefs in the past have included algae, corals, calcified 

sponges (such as the now extinct ‘archaeocyathids’ and ‘stromatoporoids’), bryozoans, bivalves 

and crinoids. The ancestors of modern-day stony (scleractinian) corals first appeared about 250 

million years ago, during the Triassic, and flourished as the prominent reef builders for many 

periods during the more recent Jurassic (190–150 million years before present) and Cretaceous 

(150-65 mybp). Like other ecosystems, they were disrupted by the mass extinction events 

caused by meteors and volcanic eruptions that also resulted in major climate changes. The 

Cretaceous-Tertiary extinction event 65 million years ago resulted in the extinction of many 

coral species, but corals eventually re-established their position as the dominant reef-builders 

about 36 million years ago (Oligocene). There is strong evidence that the beneficial symbiosis 

that these reef-building corals developed with dinoflagellates (the zooxanthellae) arose about 

that time and may be a major reason for their success. The last major disruption to reefs, or at 

least a shrinking of their habitat, was the ice age between the Pleistocene (last period) and the 

Holocene (current period) when sea levels fell between 110 and 120 m, exposing the shallow 

living reefs to the air, thereby ‘forcing’ reefs to grow downwards on near vertical continental 

slopes. When that ice age ended at the start of the Holocene, sea level rose rapidly and by about 

8000 years ago had flooded the continental shelves, thus greatly expanding the area for modern 

coral reef growth. 

Coral reefs have a number of special features that have allowed them to develop over these 

long periods. Corals, calcareous algae and other reef-dwellers that secrete calcium carbonate 

develop the reef base that supports the entire ecosystem. It is the reef structure itself that 
Coral Reefs and Climate Change: Susceptibility and Consequences

21

provides the complex habitat that supports high biodiversity. The features of tropical coral 

reefs outlined below, are those pertinent to global climate change:

zx Corals contain photosynthetic symbiotic dinoflagellate algae, ‘zooxanthellae’, that 

provide them with abundant energy and assist in nutrient recycling, allowing them 

to survive in generally low nutrient tropical and sub-tropical oceans;

zx The large amounts of energy made available to the corals by zooxanthellae enables 

rapid growth and skeletal development, thereby assisting them to compete effectively 

with other organisms such as sponges and macroalgae (seaweeds);

zx Many corals currently live near their maximum temperature tolerance. This aids more 

rapid biochemical reactions, but it leaves them vulnerable to small perturbations in 

temperature;

zx Coral reefs occur in the shallow parts of the photic zone, although they often occur 

as deep as 60 m in clear waters. Their distribution into more temperate zones may 

be limited to progressively shallower habitats at higher latitudes, primarily because 

of light limitations in winter;

zx The habitat complexity that provides niches for many reef animals and plants depends 

on the morphological structure of many corals; e.g. branching coral species provide 

a structurally complex habitat, whereas massive corals provide a solid, stable base. 

Thus, selective elimination of certain types of species will have repercussions across 

the community;

zx Many animals (e.g. fish, crustaceans, worms) depend on corals for both habitat and 

food. Many of these have co-evolved complex symbioses; e.g. gall crabs and some fish 

(damselfish, butterflyfish, and some gobies) only live on a few coral species. 

While coral reefs are long-lived and relatively resilient structures, they are still sensitive to 

disturbance such as excessive wave action, changes to the clarity of the water through excess 

sediment input resulting from damaging human activities, pollution and the effects of overfishing. Now global warming and ocean acidification are developing as additional major threats 

to their future viability, with some of the first impacts already being felt. 

The predominant threats associated with climate change are increasing sea surface temperatures 

and ocean acidity, sea level rise, and the potential for weather changes, including more frequent 

and intense cyclonic storms. In addition, climate change will involve other stressors such as 

the increased incidence of disease in coral colonies weakened by bleaching, possible shifting of 

ocean currents and rises in the incident UV radiation associated with some greenhouse gases 

that also deplete atmospheric ozone.

1. Rising Sea Surface Temperatures

Sea surface temperatures have been steadily rising in tropical/subtropical waters; e.g. they rose 

by an average of 0.3o

C between the 1950s and 1990. It is likely that reef-building corals are now 

1–1.5oC closer to their upper thermal limits than they were 100 years ago, with the result that 

warmer than average years, arising as a result of natural variability, now push corals beyond their 

upper thermal thresholds. Sustained temperatures as little as about 1–2oC above the normal 

summer maximum are sufficient to stress corals, and cause them to bleach. Bleaching is a 

generalized response to stress that could arise because of changes to the physical and chemical 
Status of Coral Reefs in the Caribbean after Bleaching and Hurricanes of 2005

22

environment. When sea temperatures exceed the summer maximum by approximately 2–3oC 

for about 4 weeks under clear tropical skies, corals bleach; that is, they usually expel their 

brown symbiotic algae and reveal either the pale pastel colors of the host pigments, or bleach 

brilliant white. 

We understand some of the mechanisms behind the temperature stress responses of corals. 

Thermal stress damage starts in the photosynthetic system of the symbiotic zooxanthellae, 

causing a collapse of the light processing mechanisms, such that the excess light is diverted 

from normal photosynthesis to producing excess free oxygen radicals. These are toxic to the 

coral and the symbiosis falls apart, resulting in the corals ejecting the algae, their major source 

of energy. While the first damage is to the photosynthetic mechanisms of the algae, other 

aspects of the coral-zooxanthellae symbiosis are also damaged. Thus, many corals are highly 

sensitive to changes in sea temperature.

Bleached corals may recover their symbiotic zooxanthellae if the temperature stress is mild or 

short-lived; but if it is more intense or long-lived, corals begin to die or they may be affected in 

other ways. For example, reproduction and growth may be affected for up to two years after a 

bleaching event, thus frequent bleaching events will have major impacts on the corals and the 

reefs they build. Evidence from the field also indicates that stressed corals are more vulnerable 

to pathogens that may occur on the outer cell surface layer, resulting in more disease in such 

colonies. 

Corals around the world have developed upper thermal thresholds that are close to local 

maximum temperatures; corals that live in cooler waters at higher latitudes will bleach at 

much lower temperatures than corals in warmer, more tropical waters. These differences are 

the result of past adaptation (evolution) to the local temperatures by corals over thousands 

of years. The rates of sea temperature changes predicted by models of global climate change 

indicate that coral bleaching will be more frequent and severe in the future. Bleaching was 

virtually unheard of 30 years ago; now bleaching occurs in some places as frequently as every 

3–4 years and could become an annual event in the near future. 

Why most potential adaptation mechanisms will not work: A core assumption in the 

predictions of rapid reef decline is that there will be insufficient genetic change in the corals 

to keep pace with climate change. The thermal stress thresholds of corals have been relatively 

stable over several decades and have shown no tendency to shift upwards. However, bleaching 

and mortality are increasing, which indicates that stress thresholds are not changing rapidly 

enough to prevent bleaching in rapidly warming seas. 

One alternative hypothesis is that corals, via their symbiont zooxanthellae, may evolve rapidly 

through the acquisition of more thermally tolerant symbionts. If new symbiotic relationships 

can be rapidly formed within a few decades, corals will become more thermally tolerant, 

allowing them to keep pace with rapid climate change. Unfortunately there is no evidence 

that corals can form new symbiotic relationships easily, or that thermal tolerances will rise 

sufficiently to protect coral reefs from bleaching. No lasting changes have been observed in 

coral-zooxanthellae partnerships before and after major bleaching events. 

The 2007 Intergovernmental Panel on Climate Change Report (IPCC 4th Assessment Report) 

predicts that climate change will continue for hundreds of years, with increases in greenhouse 
Coral Reefs and Climate Change: Susceptibility and Consequences

23

gases such as CO2. Current predictions of future coral reef bleaching events indicate that corals 

will not adapt to warmer water without either a stabilization of greenhouse gas emissions or 

even a decrease. If low emission technologies result in global temperatures stabilizing at 2oC 

above the present, coral populations will initially decrease with the loss of temperature sensitive 

species, until they are replaced by more temperature resistant species. That will take decades 

if not centuries. However, if greenhouse gases do not stabilize, the most likely scenario is that 

coral populations will decrease, with growing rates of extinction of corals and the thousands of 

other species that depend on coral reefs. This will mean an end to the all-important ecological 

services provided by coral reef ecosystems.

2. Increasing Concentrations of CO2 in Seawater

The cascading effects on ocean chemistry of rising atmospheric CO2 levels are referred to 

as ‘ocean acidification’. This does not generally invoke the same sense of urgency as coral 

bleaching, probably because:

zx it is a creeping environmental problem; 

zx ocean acidification has only recently been accepted as a reality (partly because 

seawater carbonate chemistry is not intuitive); and 

zx the process is relatively invisible and does not appear to physiologically harm adult 

corals. 

How ocean acidification will affect all life stages of organisms, reef communities, and reef 

structures, however, is largely unstudied. While the nature and rate of ocean acidification is 

well-known and predictable, the potential ecosystem effects of ocean acidification constitute a 

problem of high uncertainty, but high risk.

The uptake of atmospheric CO2 by the oceans is a double-edged sword. So far, the oceans have 

absorbed about a third of the excess CO2 released into the atmosphere from burning fossil fuels 

and other human activities. Another third has been taken up by activities on the land, and the 

remaining third has remained in the atmosphere such that the concentration of CO2 has gone 

from 280 parts per million by volume (ppmv) before the industrial revolution to about 380 ppmv 

today. Ocean uptake of CO2 from the atmosphere reduces the severity of the greenhouse effect 

and climate change (and indeed the conditions that cause coral bleaching). Unfortunately, it 

also alters the chemistry of seawater resulting in lower pH (‘ocean acidification’) and decreased 

carbonate ion concentrations. Low pH values represent high hydrogen ion concentrations 

and more acid conditions, and high pH values represent low hydrogen ion concentration 

and alkaline conditions. pH is reported on a logarithmic scale; such that a 1.0 change in pH 

represents a 10-fold change in hydrogen ion concentration. The pH of tropical seawater has 

remained around 8.2–8.3 for about a half million years, but will decrease to around 7.9–8.0 when 

atmospheric CO2 concentrations are double the pre-industrial levels; that represents about a 

30% increase in hydrogen ion concentration. This change in ocean acidity will also cause a 

shift in the relative proportions of the inorganic forms of carbon: dissolved CO2

; bicarbonate; 

and carbonate. A lowering of seawater pH also means that the carbonate ion concentration will 

decrease by more than 30%. This represents a substantial change in the chemical conditions 

supporting calcification, because the carbonate ion is a major skeletal building block for the 

calcium carbonate (CaCO3) skeletons of corals and other reef-building organisms. 
Status of Coral Reefs in the Caribbean after Bleaching and Hurricanes of 2005

24

The significance of these changes: Experiments with corals and coral communities cultured 

in predicted future seawater chemistry conditions show that calcification rates will decrease by 

20–50% of pre-industrial levels by 2050 (the predicted date for a doubling of atmospheric CO2 

concentrations). However, there will be variations in calcification rates between species, and 

DEEP-SEA CORALS AND OCEAN ACIDIFICATION

Most people are familiar with tropical coral reefs, but many are unaware of the wide 

distribution of deep-sea corals that live in cold waters below the photic zone, in depths 

of 50-1000 m. The scientific world was unaware of the vast expanses of ‘deep-sea coral 

bioherms’ that occur along the edges of continental shelves until a few decades ago, when 

underwater mapping by remote cameras came into common use. These coral ecosystems 

are known to support many fisheries, particularly in the North Atlantic Ocean and off 

the coast of Alaska. A major threat to these communities has been bottom trawling, 

which physically destroys these slow-growing reefs. Now the global problem of ocean 

acidification is threatening their existence.

Deep-sea corals are considered to be particularly sensitive to ocean acidification because 

they often grow just above depths where waters become under-saturated with calcium 

carbonate. As CO2

 concentrations rise and ocean acidification proceeds, that depth is 

‘migrating’ upwards, and many deep-sea coral ecosystems will soon be immersed in 

under-saturated waters. Since the distribution of cold water corals today appears to be 

limited to depths above the saturation depth, it is likely that the deeper coral ecosystems 

will disappear.

Guinotte JM, Orr J, Cairns S, Freiwald A, Morgan L, George R (2006). Will human-induced 

changes in seawater chemistry alter the distribution of deep-sea scleractinian corals? 

Frontiers in Ecology and the Environment 4:141-146.

This diagram illustrates what will happen to ocean chemistry as more CO2 dissolves in seawater. 

When CO2 concentrations in the atmosphere effectively double from the pre-industrial levels, there 

will be an increase in dissolved bicarbonate and a decrease in the available carbonate in seawater. 

Thus it will become more difficult and energy consuming for coral reef animals and plants to make 

skeletons. 

Atmospheric carbon dioxide

CO

Dissolved 

carbon dioxide

Carbonic acid Bicarbonate Carbonate

CO H CO HCO + H CO + H

560

CO

ppmv

280 8

16

1635

1867

Preindustrial versus doubled preindustrial CO2 concentrations

272

177

8.11

7.93

CO + H CO

μmol kg

HCO 

μmol kg

CO 

μmol KG

pH

CO + H O 2 2

2 (aq) 2 3

2 (g)

3

–

3

2–

2 (g) 2 (aq) 2 3 –1 –1 –1 3 3

2 –

+ +

–
Coral Reefs and Climate Change: Susceptibility and Consequences

25

particularly between major organism groups. This will depend on where calcification occurs 

(e.g. intracellular versus extracellular), and the biological mechanisms of calcification. A 

puzzling aspect of biological calcification is that corals and other calcifying organisms have the 

ability to isolate calcifying fluids and strongly control the chemistry of those fluids. Why will 

the chemistry of the external seawater strongly affect the calcification rates? There are several 

hypotheses on the coupled nature of calcification and photosynthesis, but no hypothesis has 

been fully accepted by the science community.

Coral calcification is not only determined by seawater carbonate chemistry, but also by other 

factors such as temperature, light and nutrients. Evidence that coral calcification rates are 

declining is now appearing in the scientific literature although some studies up until the early 

1980s recorded a rise in calcification over the majority of the 20th century. The increase is 

probably a result of global warming, because many coral species calcify faster in warmer waters. 

Coral calcification rates increase with rising temperatures to some optimal temperature, 

which is near the summer maximum. Calcification then declines when temperatures exceed 

this maximum. This appears to have been happening over the past 15 years, during which time 

calcification rates have started to decline, most probably because of the combined impacts of 

increasing thermal stress and the reduced availability of carbonate ions.

Our understanding of how rises in atmospheric CO2

 will affect seawater chemistry has greatly 

improved over the last decade. There is little doubt that the carbonate system in seawater 

is changing according to predictions, and evidence is mounting that calcification rates will 

decrease, and carbonate dissolution rates will increase. The main area of uncertainty relates 

to how changes in calcification and dissolution will affect an organism’s fitness and survival. 

Several functions of CaCO3 precipitation have been proposed, but there have been few studies 

to test how they affect the organism or the community. Some coral species grown under 

extremely high CO2 levels completely lost their ability to secrete skeletons; but regained their 

skeleton-building ability when conditions returned to normal. This is hopeful news that some 

coral species can survive without their skeletons, but even if ‘naked’ corals survive they will not 

retain their original ecological functions and roles within coral reef communities. 

Coral reef ecosystems are unique because the excess production of calcium carbonate results 

in building the reef; the very basis of a coral reef habitat. As calcification rates decline and 

dissolution rates rise, the balance between reef growth and reef destruction will also change. 

Reefs that already have a low surplus of carbonate production, e.g. those at high latitudes, 

may shift from net reef building to net reef loss, and lowered calcification rates will reduce the 

ability to keep up with rising sea levels.

3. Sea Level Rise

The 2007 4th IPCC Report suggests that there will be a rather modest sea level rise of 20–60 

cm by 2100, principally caused by thermal expansion of the oceans but including some melting 

of glaciers and ice caps. However, the authors of this report acknowledge that the models 

did not include processes related to increased ice flow. It is also important to realize that the 

inherently conservative consensus opinion of the fourth assessment report of the IPCC does 

not include some of the perspectives of the expert committee on sea level. When these opinions 

are included, the prospect of much higher sea level rise over the 21st century becomes a greater 

reality. For example, continued melting of the Greenland ice sheet could cause an additional 
Status of Coral Reefs in the Caribbean after Bleaching and Hurricanes of 2005

26

Function Description

Protection Skeleton protects organism from predators, strong 

hydrodynamic conditions, sedimentation, etc.

Enhances photosynthesis In photosynthetic calcifiers, calcification releases protons 

that converts bicarbonate to CO2

Light modification CaCO3 skeleton enhances light field for photosynthesis by 

focusing and reflecting light

Reproduction Colony size sometimes determines fecundity or age of 

reproductive maturity; rates of fragmentation may be 

affected by skeletal density

Anchoring to substrate Secures the organism to the substrate, may also affect 

initial settlement of recruits

Extension above the bottom Upward growth limits time that an organism is subjected 

to bottom sedimentation or scour 

Competition for space, light and 

other resources

Many reef-builders compete for space and light by growing 

faster than their competitors

rise of a meter or more this century, and with complete melting, an additional 6–7 m rise in 

sea level over the next few centuries. Such rises would not normally pose problems for most 

coral reefs; indeed sea level rise provides more space for corals to grow upwards without being 

exposed to the air. 

There will, however, be major problems for islands and low lying coastlines. Coral cays develop 

via a combination of winds and waves concentrating carbonate sediments; seeds and vegetation 

carried in by winds and birds help to consolidate these sediments. The combination of sea level 

rise and possibly more tropical storms will counteract any accretion. A reduction in carbonate 

production because of ocean acidification will add another negative factor. Many of these coral 

islands and atolls in the Pacific and Indian Oceans, and in the wider Caribbean will become 

uninhabitable as seawater washes over the islands during storm surges, penetrates into the 

fresh groundwater and disrupts food crops. There are no predicted mechanisms for the sand on 

these islands to build up sufficiently rapidly to keep up with expected sea level rise; therefore 

human populations will be displaced and parts of some countries including the Bahamas and 

Colombia, and whole Indo-Pacific states such as Tuvalu, Kiribati, the Marshall Islands and the 

Maldives may cease to exist. 

4. Possible Shifting of Ocean Currents

We have a good understanding of how coral reef ecosystems will be affected by ocean warming, 

acidification, and sea level rise; however, we know less about other factors associated with 

climate change. Changing climate conditions may cause oceanic currents to slow or even 

change direction; and large scale events such as the El Niño Southern Oscillation may change 

in frequency and/or intensity. Given that currents connect coral reefs to other coral reefs and 

related marine ecosystems, these changes could have profound effects on the sustainability and 

management of coral reef ecosystems.

The list below details some of the functions of Calcium Carbonate skeletons in reef-building 

organisms. 
Coral Reefs and Climate Change: Susceptibility and Consequences

27

5. Associated Changes in UV Radiation Intensity

The incidence of UV radiation in the tropics is usually very high, particularly in passing through 

the clear waters bathing coral reefs. Most coral reef animals have evolved structural, chemical 

and behavioral mechanisms to cope with UV radiation. Thus, no major problems are anticipated 

with predicted thinning of the ozone layer and a likely increase in UV radiation. Shifting ocean 

currents and sediment input may cause changes in the clarity of the water column, which will 

change visible and UV radiation penetration.

6. Weather, Hurricanes and Storms

Global climate change predictions all emphasize greater variations in weather, such as more 

intense periods of rainfall followed by longer periods of drought. Such climate changes over 

land will affect runoff and sedimentation (which are also affected by land-based human 

activities), and affect water quality on many reefs. More extreme rainfall events, for example, 

will intensify flooding and river-plume damage to reefs, while a decrease in rainfall should 

lead to improvements in water quality. Tropical cyclonic storms have become more frequent 

and intense in some regions such as the Caribbean since about 1970, with some evidence that 

this is fuelled by warmer oceans. Climate models predict that cyclones are likely to be more 

intense, with more category 4 and 5 storms; but the number of storms may not necessarily 

increase (see Page 14). Strong storms can cause massive damage to coral reefs; for example 

Hurricane Andrew in 1992 severely damaged the coral reefs in Florida and other parts of the 

Caribbean through violent wave impacts. A rise in storm intensity or frequency may put reefs 

into a permanent state of recovery, because it takes about 10–15 years for a reef to recover from 

a major storm. How stronger storms are likely to affect reefs is reviewed in the next chapter.

Synergies, Consequences and Opportunities for Management Intervention

Corals build the framework of coral reefs and therefore support thousands of other species. Many 

of these are totally dependent on corals for food, shelter and reproduction, and will disappear 

with a loss of coral. Other reef organisms rely only partly on the corals, perhaps needing only 

the complex structure for survival. The loss of coral will result in some local extinctions and 

reduced diversity of fish species. For example, some fish species are more sensitive than others, 

with corallivorous (coral eating) species being the most sensitive; herbivores may actually 

multiply because there will be more algae to eat. It is probable that many of the large food 

fish and visiting pelagic fish will not be markedly affected, but our knowledge of these systems 

is not sufficient to predict which species will or will not show changes with climate change. 

Several recent estimates suggest that as much as 50% of the fish diversity currently on coral 

reefs will disappear if coral communities are severely damaged.

An understanding of how coral dependent organisms on reefs will change with the loss of corals 

is still being developed. However, given the extremely tight relationships between organisms 

and corals, the loss of corals will almost certainly be accompanied by the loss of many thousands 

of species. It is also important to realize that corals may not have to completely disappear to 

cause big effects on the organisms that use them as habitat. For example, some coral dwelling 

species may require dense coral populations to enable them to live close enough to the opposite 

sex for reproductive success.
Status of Coral Reefs in the Caribbean after Bleaching and Hurricanes of 2005

28

Some climate change impacts, particularly in combination with other influences, will likely 

reduce the overall resilience of coral reefs. Changes in a coral community (such as reduced 

biodiversity) may severely undermine system resilience, resulting in a phase shift to a noncoral reef community. For example, the loss of some fish and invertebrates may leave a coral 

reef more susceptible to episodic outbreaks of pests or invading species. Effects like this tend 

to be unpredictable, but such unpredicted changes are likely to increase.

Climate change also affects coral reefs in another, fundamental way that is unique to this 

ecosystem; that is the effects on the geological reef structure itself. Reduced coral cover (e.g. 

from coral bleaching) coupled with lowered calcification rates and increased dissolution rates 

(ocean acidification) will reduce the net calcium carbonate production rates on reefs. By the 

end of this century, the overall balance of carbonate production on many reefs is expected to 

decline to the point where reef-building may cease or reverse. In addition, any ecosystems that 

are influenced by the reef structure and reef sediment production will also be affected. These 

could include mangroves, seagrass beds, and low-lying coral cays. It might also have significant 

implications for human infrastructure on coastlines protected by coral reefs.

Against the background of these dire predictions facing coral reefs, implementing management 

of local damage may seem irrelevant unless the current growth in greenhouse gas emissions 

is constrained. Even with drastic reductions in CO2

 concentrations, there will be changes 

and challenges for coral reefs. However, after the massive coral bleaching in 1998, coral reefs 

recovered better and more rapidly where stresses related to poor water quality and overfishing were well managed. For example, where grazing fish are retained on a reef, corals will 

repopulate damaged areas 2–3 times faster than on over-fished reefs; similarly, growth rates 

of corals are faster in non-polluted waters. Managing local stresses on reefs may not prevent 

damage from climate change, however it will enhance recovery.

Recent evidence indicates it is imperative that there is strong action on reducing greenhouse 

emissions to ensure that we don’t exceed much more than 450-500 ppm CO2 in the atmosphere. 

Any response, however, must include local strategies to increase the effective management of 

local stresses, such as declining water quality and overfishing, damaging coral reefs. Reefs will 

persist longer under the stresses of the next 50–100 years if they are given the best chance of 

recovering from the inevitable ecological shocks; this will ‘buy time’. These two approaches, 

decreasing emissions and increasing protective management, are an integral part of effectively 

addressing the current coral reef crisis and are discussed in Chapter 10, p. 115.

Author Contacts

Joan Kleypas, National Center for Atmospheric Research Boulder, Colorado, USA, kleypas@

ucar.edu; Ove Hoegh-Guldberg, Centre for Marine Studies, University of Queensland, Australia. 

oveh@uq.edu.au 

References

Fine M, Tchernov D (2007). Scleractinian coral species survive and recover from 

decalcification. Science 315:1811. 

Hoegh-Guldberg O, Mumby PJ, Hooten AJ, Steneck RS, Greenfield P, Gomez E, Harvell DR, 

Sale PF, Edwards AJ, Caldeira K, Knowlton N, Eakin CM, Iglesias-Prieto R, Muthiga 

N, Bradbury RH, Dubi A, Hatziolos ME (2007). Coral reefs under rapid climate change 

and ocean acidification. Science 318 (5857): 1737-1742. 
Coral Reefs and Climate Change: Susceptibility and Consequences

29

IPCC (2007). Climate Change 2007: The Physical Science Basis. Summary for Policymakers. 

Contribution of Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change. 18 pp.

Kleypas JA, Langdon C (2006). Coral reefs and changing seawater chemistry, Chapter 5 in Coral 

Reefs and Climate Change: Science and Management, Phinney JT, Hoegh-Guldberg O, 

Kleypas J, Strong A, Skirving W (eds), AGU Monograph in Coastal and Estuarine Series, 

Am. Geophys. Union, Washington DC, Vol 61, pp 73-110.

Kleypas JA, Feely RA, Fabry VJ, Langdon C, Sabine CL, Robbins LL (2006). Impacts of Ocean 

Acidification on Coral Reefs and Other Marine Calcifiers. A Guide for Future Research,

Report of a workshop sponsored by NSF, NOAA and the USGS. 88pp. (http://www.isse.

ucar.edu/florida/)
31

Background to Hurricanes

A hurricane (also tropical cyclone, typhoon) is a warm-core, low-pressure system that develops 

over tropical or subtropical waters. Most hurricanes form from a trough of low-pressure, 

over ocean surface temperatures greater than 26°C. As air moves across the ocean surface, 

it extracts moisture (water vapour) and energy (as a result of evaporation) from the ocean. 

The low pressure draws air inward, causing the water vapour to rise, cooling as it rises. When 

the vapour condenses to form clouds, it transfers the heat energy to the surrounding air. As 

the warm air rises higher in the atmosphere, it lowers the pressure at the ocean surface. This 

causes more air to enter at the ocean surface, which creates stronger winds and continues 

to transfer heat from the ocean into the atmosphere. As long as the atmospheric conditions 

are favourable and the ocean can provide the energy, this creates a feedback mechanism to 

strengthen the hurricane. 

When fully-formed, hurricanes are well organised with a calm eye at the centre surrounded 

by an eye-wall where the strongest winds and most of the ocean heat extraction occurs, as 

illustrated in the figure below. Several rain bands can encircle the eye, also extracting smaller 

amounts of heat from the ocean. As a hurricane moves, it typically leaves a cool wake behind it 

(see ref. 3.) and pushes waves out in all directions. If a hurricane approaches land, these waves 

steepen and water piles up in the shallows, often pushing up onto the land. This phenomenon 

is called a storm surge and can be particularly damaging if it occurs during high tide. The 

greatest surge is usually generated in front of and to the right of a northern hemisphere 

hurricane (left front quadrant in the southern hemisphere).

3. Hurricanes and their Effects on Coral Reefs

Scott Heron, Jessica Morgan, Mark Eakin and William Skirving
32

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

This diagram illustrates how a hurricane forms over warm ocean waters and starts spinning 

in a counter-clockwise direction in the Northern Hemisphere. Large storm waves may result in 

significant coral reef damage. However, a hurricane will also cool surface waters and can often 

mitigate coral bleaching.

While there is a minimum ocean surface temperature for hurricanes to form, the energy 

that drives a hurricane is supplied by the upper section of the water column, not just the 

surface. Hurricane intensity is more closely linked to the ocean heat content than to surface 

temperature alone (4.). Once the eye of a hurricane moves over land it experiences greater 

friction and loses its source of moisture and heat, causing it to weaken. Hurricanes can 

also weaken at sea if their energy source is reduced by encountering cool waters (fronts, 

upwellings), or their vortex development is inhibited by entering a zone of high vertical wind 

shear.

Hurricanes help to regulate the earth’s temperature, extracting heat from the ocean and 

redistributing it into the atmosphere; thereby moving tropical heat poleward. In the absence 

of regular hurricanes, tropical oceans retain more heat, which can then lead to larger, more 

intense hurricanes. Recent increases in ocean temperatures, very likely due to human-induced 

climate change, have seen tropical storms becoming stronger but not necessarily increasing 

in number (7. and Executive Summary p. 14).

Globally averaged land and ocean temperatures in 2005 were the highest on record according 

to NOAA and NASA analyses, with temperatures slightly warmer than in 1998. The 2005 

hurricane season in the Atlantic and Caribbean was unprecedented, experiencing more 

than twice the annual average of named tropical storms over the past century and the 

greatest number of hurricanes in recorded history. While some of this may be attributed to 

improvements in hurricane observation skills through satellites and other instruments, there 

can be no doubt that 2005 was an extreme year for storm activity.

Waves

Upwelling

Eye

Warm water

Storm surge

Corals

Cool wake Latent

heat

Well-mixed water column Turbulent

mixing

Hurricane Motion

Latent

heat

Eye wall

Waves

Rain bands

Eye wall

Rain bands
33

Hurricanes and their Effect on Coral Reefs

Hurricane Category Impacts

1 Wind 64-82 knots, storm surge 1.0-1.6 m, no real damage to 

building structures, damage to trees

2 Wind 83-95 knots, storm surge 1.7-2.5 m, some roofing and window 

damage, considerable damage to trees

3 Wind 96-113 knots, storm surge 2.6-3.8 m, some building damage, 

large trees blown down

4 Wind 114-135 knots, storm surge 3.9-5.5 m, complete removal of 

some roofs, extensive window damage, most trees blown down

5

Wind 136+ knots, buildings fall over, storm surge 5.6+ m, 

widespread loss of roofs, some buildings destroyed, all trees blown 

down

(a wind speed of 100 knots = 185.2 km per hour = 51.4 metres per second)

So Why was 2005 so Active?

Several factors are involved. There was an extensive region across the equatorial Atlantic 

where the vertical wind shear (the change in wind speed with height) was unusually low. 

Vertical wind shear interferes with the vertical structure of a hurricane and inhibits hurricane 

formation. The rate of latent heat exchange (the transfer of water vapour energy from ocean 

to atmosphere) was 20% greater than the largest value in the previous 25-year period and, 

therefore, strongly favoured hurricane activity. Record warm surface temperatures across 

the Gulf of Mexico, Caribbean and tropical Atlantic provided the energy source to form and 

sustain hurricanes. Sea-level pressure was exceptionally low across the Caribbean, again 

aiding hurricane formation (5.).

Many of these factors have been linked to climate-scale variabilities. Perhaps the most wellknown of these is the El Niño-Southern Oscillation (ENSO); however, during 2005 conditions 

were ENSO neutral for most of the year. Other large-scale variabilities that have been 

linked to observed oceanic and atmospheric conditions include the Atlantic Multi-decadal 

Oscillation, the North Atlantic Oscillation and the Madden-Julian (40-day) Oscillation. It was 

the juxtaposition and magnitude of these causal factors that likely induced the record activity 

during the 2005 hurricane season. The effect of these was exacerbated by climate change, the 

largest contributor to the warm temperatures in the tropical Atlantic. Of the 0.9°C tropical 

Atlantic temperature anomaly (compared with a 1901-1970 baseline), 0.2°C was attributable 

to the weak 2004-05 El Niño; less than 0.1°C was attributable to the Atlantic Multi-decadal 

Oscillation; and most of the anomaly (0.45°C) was attributable to climate change (6.).

A side-note to the extreme nature of the 2005 season is that none of the named storms 

traversed Puerto Rico and the Lesser Antilles (Windward and Leeward Islands). Despite the 

Hurricanes are classified by their wind speed in the well-known Saffir-Simpson scale. Category 1 

storms have sustained wind speeds greater than 64 knots (33 m/s) and generally cause only minor 

damage upon landfall; Category 5 hurricane winds exceed 135 knots (69 m/s) and can devastate 

structures with both winds and storm surge.
34

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

very warm ocean surface temperatures, each of the Atlantic hurricanes passed around this 

region. While this absence of storm activity saved the island communities from the potential 

devastation of hurricane landfall, it also removed the ameliorating effects that tropical storms 

have for tropical regions.

This figure illustrates the named storm tracks (including hurricanes) for 2005. Dotted 

lines show paths of tropical storms; hurricane strength is shown by the thickness of the 

solid lines (3 groups: categories 1; 2 & 3 together, 4 & 5 together). The marked track is 

of Hurricane Katrina whose storm surge devastated New Orleans. Note the clear region 

centred around 65o

W:20oN; no hurricanes passed over the very warm waters, which 

resulted in massive coral bleaching in the Lesser Antilles . Compare this ‘hole’ with the 

NOAA thermal stress images on the front cover and on pages 9-11.

The Good and the Evil of Hurricanes for Coral Reefs

While there is often a perspective that hurricanes are only destructive and disastrous events, 

they also provide ecological benefits to tropical and sub-tropical environments. Rainfall gives 

a boost to wetlands and flushes out lagoons, removing waste and weeds. Hurricane winds 

and waves move sediment from bays into marsh areas, revitalising nutrient supplies. While 

there is always the potential for mechanical damage, coral reefs can also receive benefit from 

hurricanes during the warm summer months (1.).

During the summer hurricane season, as ocean surface waters become warmer, corals often 

experience thermal stress. Hurricanes can alleviate this thermal stress by three mechanisms. 

First, as hurricanes absorb energy from surface waters through the transfer of latent heat, the 

temperature of the water is reduced (evaporative cooling). The magnitude of the cooling is 

related to the intensity and extent of the hurricane. Second, hurricanes also reduce sea surface 
35

Hurricanes and their Effect on Coral Reefs

temperatures (SST) by inducing local upwelling, bringing deeper, cooler water to the surface. 

The amount of surface cooling resulting from these mixing mechanisms will depend on the 

hurricane wind speed and how the water temperature varies with depth at each location. 

Finally, the clouds of a hurricane shade the ocean surface from solar heating allowing the 

water to cool and reducing light stress.

The figure on the left shows regions of positive and negative sea surface temperature anomaly with 

the track of Hurricane Katrina over the cool wake. The graph on the right is a SST time-series at 

Sombrero Reef, Florida Keys showing the rapid drop in temperature following the passage of hurricanes Dennis (D), Katrina (K), Rita (R) and Wilma (W). Hurricane Katrina passed over the Florida 

Keys as a Category 1 hurricane on 26 Aug 2005, during the hottest period, reducing the temperature 

stress and halting a temperature trajectory towards coral bleaching.

While larger, more intense hurricanes provide the greatest cooling near the ocean surface, 

they are also the most destructive. Waves and water movement significantly influence the 

structure and distribution of coral assemblages. Generally, the more delicate ‘branching’ 

corals (e.g. Acropora spp.) are more vulnerable to wave damage than corals with a ‘massive’ 

or ‘boulder-like’ growth form (e.g. Porites spp.). As a consequence, massive corals tend to 

dominate coral communities in areas regularly exposed to oceanic swells, while delicate 

species thrive in low energy areas such as lagoons and back-reef areas (2.). In addition, waves 

and tidal water movements scour some areas exposing the solid limestone structure of the 

reef, which provides a firm foundation on which corals can settle and grow. In other areas, 

water movement results in the accumulation of sediment and rubble, which is unstable and, 

therefore, less suitable for coral settlement. 

The waves generated by hurricanes are larger and more powerful than those experienced 

under normal conditions and can affect all parts of a reef. As a consequence, they are the 

primary cause of hurricane-related damage to corals and coral reefs, often breaking coral 

branches and overturning colonies. Dislodged coral pieces can cause further damage as they 

are propelled onto other parts of the reef. In 2005, Hurricane Rita damaged the deep reefs of 

the Flower Garden Banks, while Wilma scoured the reefs of the Florida Keys.
36

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Recovery from hurricane damage is variable. Often, branching corals recover quickly because 

of their rapid growth, and broken branches can even begin to regrow in new areas. However, 

recovery can be hindered by the accumulation and movement of coral rubble generated by 

the hurricane, and by increases in the abundance of algae, which compete for space within 

the reef. Terrestrial runoff resulting from heavy rainfall can also influence the nearshore reef 

ecosystems, smothering corals with sediment and other debris, as well as increasing nutrients 

(including those in fertilisers) that influence growth rates of algae, and lowering salinity, 

which can stress corals.

Conclusions

The influence of hurricanes on coral reefs can be beneficial and detrimental. Small hurricanes 

can provide fast relief during periods of thermal stress, whereas waves from large hurricanes 

can reduce a reef to rubble. Coral reefs have experienced these effects of hurricanes and 

survived for millions of years; however, in light of the rapidly changing climate, the ability of 

corals to recover from severe storms, while facing the combined effects of increasing thermal 

stress and ocean acidification, could be extinguished.

Acknowledgements

Information was extracted from the following source and the authors would like to acknowledge 

their contribution: NOAA National Hurricane Center, www.nhc.noaa.gov

Author Contacts

Scott Heron, Jessica Morgan, Mark Eakin and William Skirving, NOAA Coral Reef Watch, 

SSMC1 Rm5308, 1335 East West Hwy, Silver Spring MD 20910, USA, scott.heron@noaa.gov, 

jessica.morgan@noaa.gov, mark.eakin@noaa.gov, and william.skirving@noaa.gov.

References

1. Manzello DP, Brandt M, Smith TB, Lirman D, Hendee JC, Nemeth RS (2007). Hurricanes 

benefit bleached corals. Proceedings of the National Academy of Sciences 

104:12035-12039.

2. Massel SR, Done TJ (1993). Effects of cyclone waves on massive coral assemblages on 

the Great Barrier Reef: meteorology, hydrodynamics and demography. Coral Reefs 

12:153-166

3. Monaldo FM, Sikora TD, Babin SM, Sterner RE (1997). Satellite Imagery of Sea Surface 

Temperature Cooling in the Wake of Hurricane Edouard (1996). Monthly Weather 

Review 125(10):2716–2721.

4. Scharroo R, Smith WHF, Lillibridge JL (2005). Satellite Altimetry and the Intensification of 

Hurricane Katrina. Eos Transactions 86:366.

5. Shein KA, Waple AM, Levy JM, Bourassa MA, et al. (2006). State of the Climate in 2005. 

Bulletin of the American Meteorological Society 87(6):S1, 95 pgs.

6. Trenberth KE, Shea DJ (2006). Atlantic hurricanes and natural variability in 2005. 

Geophysical Research Letters 33:L12704.

7. Webster PJ, Holland GJ, Curry JA, Chang H-R (2005). Changes in Tropical Cyclone Number, 

Duration, and Intensity in a Warming Environment. Science 309:1844-1846.
37

Coral reef scientists and managers were fortunate to have an early warning system in place prior 

to the damaging events of 2005. This chapter is a log of events that occurred in the Caribbean 

during 2005 and is largely based on messages sent out, and submissions to, Coral-List.

17-Mar-05 Coral bleaching reported on 2 reefs in Southern Bahia, Brazil (Itacolomis and 

Abrolhos); but the temperature rise is only 0.75°C above the maximum summer average. NOAA 

has not detected a major HotSpot in the satellite images; maybe this is a doldrum-like event.

16-May-05 First bad news: The U.S. National Hurricane Center has predicted a 70% chance 

of an above-normal Atlantic hurricane season. The outlook is for 12-15 tropical storms, of 

which 3-5 will become major hurricanes. This could be serious for reefs in the Caribbean. Bad 

hurricane years are often bad bleaching years as well.

26-May-05 Satellite images show potential coral bleaching and ‘HotSpots’ are appearing across 

the Caribbean earlier than usual. Winds are generally low and a pool of unusually warm water 

has formed northeast of the Lesser Antilles. NOAA Coral Reef Watch has sent out an email 

message calling for people to start checking for coral bleaching.

4. The 2005 Bleaching Event: Coral-List Log

Jessica Morgan, Scott Heron and Mark Eakin

CORAL LIST

‘Coral-List’ is a coral reef information and news email forum maintained by NOAA’s Coral 

Health and Monitoring Program, for coral reef researchers and managers throughout the 

world. Since 1995, the list has broadcast announcements and discussions of various local, 

regional, and global topics concerning coral reefs, including coral bleaching, disease and 

spawning, environmental monitoring, and upcoming meetings. Coral-List currently has 

more than 4400 subscribers. To register go to http://coral.aoml.noaa.gov/mailman/listinfo/

coral-list/. 
38

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

31-May-05 Reports are coming in from Colombia that they are seeing the highest sea surface 

temperature (SST) over the reefs so far this year, 29.9oC. Thankfully, there is no bleaching there 

... (yet).

02-Jun-05 The trade winds have begun again, mixing and cooling the waters. While this has 

provided some relief, there are still concerns about coral bleaching – and we’re only at the start 

of June!

16-Jun-05 The first Coral-List report of bleached corals for the Caribbean has come 

from the northwest coast of Colombia at Islas del Rosario, following sustained high water 

temperatures.

25-Jun-05 SSTs at Culebra, Puerto Rico, have reached 30.5°C and corals are bleaching. In 

some areas, 50% of corals have died. On top of this, there have been outbreaks of white plaguelike syndrome and black band disease. The warmest temperatures here aren’t usually reached 

until September and October.

05-Jul-05 SSTs have started to cool on the Caribbean coast of Panama but the accumulated 

thermal stress shown by the coral bleaching Degree Heating Week (DHW) values are still high. 

Corals have bleached near Bocas del Toro; hopefully this cooling will allow them to recover.

Hurricane Dennis, 05 to 13 July 2005

Hurricane Dennis was unusually strong for a July hurricane, reaching Category 4 status. 

Dennis made landfall four times; in Grenada, twice in Cuba and finally in western Florida. 

Wind speed is used to indicate a hurricane’s strength, from Category 1 (weakest) to Category 

5 (strongest) on the Saffir-Simpson scale (see Hurricane Capter).

THERMAL STRESS AND HOTSPOTS

NOAA Coral Reef Watch uses satellite sea surface temperature (SST) data to produce 

twice-weekly global estimates of thermal stress on corals (http://coralreefwatch.noaa.

gov). Thermal stress depends on the capacity of corals in different locations to tolerate 

heat; corals near the equator are comfortable in temperatures that would be stressful for 

corals that are used to cooler waters. 

Because stress thresholds are location-specific, the expected temperature for a normal 

summer is determined for each location. To measure the stress level, the current SST is 

compared with this normal summer temperature. The difference between these indicates 

the current level of stress experienced by corals and is called the ‘HotSpot.’ 

Coral bleaching HotSpot maps illustrate the magnitude and distribution of HotSpots using 

different colors that correspond to the number of degrees by which the SST exceeds the 

normal summer temperature. Examples of the maps are on pages 8 to 11)
39

The 2005 Bleaching Event: Coral-List Log 

13-Jul-05 NOAA Coral Reef Watch launches a new operational product: the Satellite Bleaching 

Alert system. 

15-Jul-05 More reports of bleaching have come in, including extensive paling of corals around 

Abacos in the Bahamas. The HotSpot image on Executive Summary page 8 illustrates the 

developing HotSpot.

Hurricane Emily, 11 to 26 July 2005

Hurricane Emily eclipsed the record set by Dennis, just 6 days earlier, as the strongest recorded 

pre-August hurricane and is the only Atlantic hurricane to have reached Category 5 status 

before August. Emily inflicted damage on Grenada as a tropical storm before intensifying in 

the western Caribbean. Emily crossed the Yucatan Peninsula (Category 4) and again made 

landfall in northern Mexico (Category 3).

26-Jul-05 Amazing! In the first two weeks of the Satellite Bleaching Alerts (SBA) system, 

emails have been sent for all 6 Caribbean/Atlantic sites. The U.S. Virgin Islands have thankfully 

dropped back to a condition of no thermal stress; Puerto Rico, the Bahamas, and Bermuda have 

gone up to Bleaching Watch, while Belize has dropped down to Bleaching Watch. There is some 

concern for the Florida Keys; there is a Bleaching Warning there at the moment.

02-Aug-05 Things have become worse; the National Hurricane Center has upgraded the 

probability of an above-normal hurricane season to 95-100%. The prediction is now for 18-21 

tropical storms, including 5-7 major hurricanes.

05-Aug-05 Corals have become pale and bleached in Bermuda where calm seas and clear skies 

are persisting and there have been reports of unusually large numbers of nudibranchs (a type 

of sea slug). Reports of sponge diseases have increased in Cozumel, Mexico; requests have gone 

out for more sightings. It is worse around St. Croix in the U.S. Virgin Islands where sponges 

appear to be absent - should we send out a search party?

08-Aug-05 Elkhorn corals (Acropora palmata) in Biscayne Bay have lost tissue following the 

passage of Hurricane Dennis through the Florida Keys. With the prediction of more hurricanes, 

will more corals lose tissue?

DEGREE HEATING WEEKS

The satellite-based coral bleaching Degree Heating Week (DHW) is an accumulation 

of thermal stress experienced by corals within the previous 12 consecutive weeks. A 

DHW value of 4°C-weeks indicates that significant coral bleaching is likely; widespread 

coral bleaching and mortality have been associated with DHW values exceeding 8°Cweeks. For each location, DHW are calculated by adding any HotSpot values greater than 

1°C and multiplying by the half-week time step of the NOAA Coral Reef Watch data. 

For example, if the HotSpot values for a particular location were [1.0, 2.0, 0.8, 1.2] the 

contribution to the DHW from these four half-week values would be (1.0+2.0+1.2)*0.5 

= 2.1°C-weeks. Note that 0.8 is not included in the calculation as it is less than 1°C. 

Examples of maps derived illustrating the distribution of DHW values can be seen on the 

first page inside the front cover; the front cover is a stylized version of this map.
40

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

18-Aug-05 Extensive bleaching has been seen in the Florida Keys, right after an SBA Alert Level 

1 email was sent on 13 August. SST has been around 31°C, with calm and sunny conditions. 

There could be more trouble in store for Florida’s reefs; a strong HotSpot is developing, as 

shown in the image on page 9. 

23-Aug-05 More bleaching has been seen in Biscayne Bay, Florida Keys, and now corals near 

Palominitos Island, Puerto Rico are bleaching.

Hurricane Katrina, 23 to 30 August 2005 

Hurricane Katrina was one of the most devastating natural disasters in the United States 

history. Katrina was the most costly hurricane to strike the U.S., making landfall in Florida 

(Category 1) and then intensifying to Category 5 over the Gulf of Mexico before striking 

Louisiana/Mississippi (Category 3). Katrina was exceptionally large with hurricane-force 

winds extending 170 km from the centre and storm-force winds out to 370 km. The 8 m 

storm surge that accompanied Katrina caused major flooding in New Orleans and along the 

northern Gulf coast. However, Katrina also did some good in the Florida Keys, as a Category 

1 hurricane, mixing up the waters and cooling overheated reefs.

SATELLITE BLEACHING ALERTS

Satellite Bleaching Alerts (SBA) notify reef managers when changes occur in the 

environmental conditions relevant to coral bleaching at or near their reef. NOAA Coral 

Reef Watch transmits emails for 24 locations around the world, including 6 strategic reef 

sites across the greater Caribbean region. SBAs are sent to registered users whenever 

HotSpot and Degree Heating Week indicators show that the thermal stress level has 

passed a critical threshold; either increasing or abating. Subscription is free at http://

coralreefwatch-satops.noaa.gov/SBA.html; additional SBA sites are under development 

and further locations can be requested.

Bleaching Watch: Keep an eye out! Corals are experiencing low-level thermal stress. 

Temperatures have exceeded the usual summer maximum but have not yet reached the 

Bleaching Threshold. Degree Heating Weeks (DHWs) are not yet accumulating.

Bleaching Warning: Get prepared now. The HotSpot is now at least 1°C and corals 

are stressed. DHWs have begun to accumulate and are at 1°C-week.

Alert Level 1: Corals are probably bleaching or will soon! DHWs have reached 4°Cweeks, signifying that thermal stress has reached levels that cause bleaching. Generally, 

corals will respond to this level of thermal stress in the next 1-3 weeks, depending on the 

species and other local factors.

Alert Level 2: Double trouble. At DHW of 8°C-weeks, thermal stress is widespread 

and you can expect to see mass coral bleaching. Unfortunately, by this time, the thermal 

stress has persisted long enough that some corals will probably die soon.

No Stress: Temperatures have cooled and hopefully stressed corals will recover. 

At least they are no longer under thermal stress.
41

The 2005 Bleaching Event: Coral-List Log 

27-Aug-05 Record-breaking thermal stress is affecting Sombrero Key in the Florida Keys and 

an SBA Alert Level 2 has been issued. Hurricane Katrina is crossing over South Florida – are 

we going from bad to worse?

29-Aug-05 According to an article in the Key West Citizen, Hurricane Katrina has really helped 

the Florida Keys, providing much-needed relief from thermal stress.

01-Sep-05 Several coral species are bleaching on the reefs of Belize, ranging in intensity from 

paling to bright white.

06-Sep-05 SST has dropped by more than 2°C at Sombrero Key from a week ago. The SBA level 

has been reduced to Bleaching Watch; hopefully these corals can recover from the thermal 

stress. The HotSpots are now covering extensive areas of the Caribbean, as seen on the image 

on page 10.

09-Sep-05 Hard corals in eastern Puerto Rico have bleached extensively, and octocorals, 

gorgonians, and zoanthids have also bleached. Water temperatures are around 29.5-30oC and 

there is barely any wind.

12-Sep-05 Things are looking bad. Corals in Biscayne Bay range from unbleached, to pale, to 

extensively bleached, and black band disease has been observed. The Florida Keys corals range 

from slight to severely bleached, and divers have reported recently-dead Elkhorn coral. Corals 

in southwestern Puerto Rico have started to bleach and white plague has also been seen.

14-Sep-05 The first bleaching of the flower coral Mussa angulosa has been recorded in 

northeastern Puerto Rico, as well as bleaching and mortality reports of Palythoa caribbaeorum. 

Bleaching has also been seen in northern and western Barbados and southeastern Costa Rica.

15-Sep-05 A report has come from eastern Puerto Rico of the first-ever record of a bleached 

colony of Elkhorn coral in the region. There has been extensive bleaching and mortality, as 

well as an outbreak of black band disease. Scientists have noted that for some reason there does 

not appear to be any cleaning gobies on the reefs - are the gobies stressed too?

17-Sep-05 Now coral bleaching has been seen in the British Virgin Islands. Are any reef areas 

safe?

19-Sep-05 Not only are hard corals, octocorals and zoanthids bleaching around Barbados, 

scientists have noted unusually high mortality of moray eels and white sea eggs (a type of sea 

urchin).

21-Sep-05 Thermal stress has progressed southward and eastward through Cuba, Puerto 

Rico and the Virgin Islands. DHW levels have exceeded 8°C-weeks, so the likelihood of coral 

mortality is high. It’s hard to not feel helpless.
42

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Hurricane Rita, 18 to 26 September 2005 

Hurricane Rita took only 36 hours to strengthen from a tropical storm to a Category 5 hurricane 

as it passed across the central Gulf of Mexico, making it the most intense hurricane ever 

recorded in the Gulf; breaking the record set by Katrina just weeks earlier. While intensifying, 

Rita passed near Florida Keys (as Category 2), mixing the waters that had begun to warm 

again following the cooling by Hurricane Katrina. Rita struck the Texas-Louisiana border as 

a Category 3 hurricane and completely destroyed some coastal communities.

24-Sep-05 Is there a weather conspiracy against corals? There is an extended area of low 

pressure over the northeastern Caribbean that means light winds for the next two weeks. 

The northern Jamaican coast has experienced low-level bleaching, but the southern coast has 

areas where 80% of the corals are bleached. There is good news, with little-to-no bleaching in 

Bonaire and Curaçao and mass coral spawning has occurred in Curaçao as usual.

26-Sep-05 It has been the hottest August and September in 15 years of ocean temperature 

monitoring at St. John, U.S. Virgin Islands! Temperatures at 16 m depth have exceeded 30°C 

since 5 September and just peaked at 30.8°C. Most coral species are severely bleached.

30-Sep-05 The Association of Marine Laboratories of the Caribbean has called for the 

establishment of a long-term monitoring program for biological communities and physical 

environment conditions on reefs. Hopefully that will help us learn how to help corals survive 

through events like this.

05-Oct-05 Devastating news; a report has been received that more than 90% of corals down 

to 30 m are bleached in the British Virgin Islands. Bleaching has also been seen along the 

northern coast of Puerto Rico. DHW values have reached record highs in these areas. There is a 

sense of helplessness in our offices; apparently all we can do is issue more threatening reports. 

The image on page 11 shows the maximum extent of HotSpots across the Caribbean.

08-Oct-05 An SBA Alert Level 2 has been issued for the U.S. Virgin Islands and DHWs in the 

region now exceed 12°C-weeks. At least 90% of corals along the northern shore of St. Croix 

are white or paled. Thankfully, the sun has now moved south, so things should begin cooling 

off (we hope!)

11-Oct-05 DHW values have continued to escalate in the eastern Caribbean; when will it stop? 

Predicted cloud and rain should bring relief from thermal stress for those regions lucky enough 

to get them.

13-Oct-05 The Caribbean coast of Tobago has experienced its worst recorded mass coral 

bleaching, with around 80% of corals affected by the 31°C conditions. Near St. Croix, U.S. 

Virgin Islands, 50-75% of hard corals and several soft coral species have bleached.

19-Oct-05 Observations in the Flower Garden Banks National Marine Sanctuary (NMS) have 

shown significant mechanical damage from the passage of Hurricane Katrina. Coral boulders 

larger than 2 m were rolled over! In addition, at least one-third of colonies have bleached.

22-Oct-05 Temperatures are in excess of 29°C down to 20 m at Guana Key in the Bahamas and 

bleaching has affected 96% of Montastraea colonies and 50% of Porites colonies.
43

The 2005 Bleaching Event: Coral-List Log 

23-Oct-05 Batten down the hatches! Coral-List has to be temporarily shutdown because of the 

imminent arrival of Hurricane Wilma and anticipated power outages.

Hurricane Wilma, 15 to 25 October 2005

Hurricane Wilma was the most intense Atlantic basin hurricane on record, with a lowest 

central pressure of 882 hPa. Wilma wreaked havoc on the Yucatan Peninsula (Category 4), 

sitting over Cozumel for more than 36 hours, before causing extensive damage in Florida 

(Category 3).

25-Oct-05 Above-normal temperatures have continued across the Caribbean. The centre of the 

heat stress has moved south along the Lesser Antilles and NOAA reports intensified bleaching 

in many areas (DHW>12°C-weeks). Bonaire and Curaçao are now seeing bleaching stress 

(DHW>4). Major newspapers, the Washington Post and Los Angeles Times, have reported the 

bleaching caused by temperature stress across the Caribbean.

27-Oct-05 Reef Check has called for the mobilization of its teams throughout the Caribbean 

for bleaching and post-bleaching surveys. Corals along the northern coasts of Colombia and 

Venezuela (20% of colonies) have bleached; in the Flower Garden Banks NMS, around 40% of 

colonies have bleached.

01-Nov-05 Scientists in Mexico are assessing the damage to corals from Hurricane Wilma. In 

the Lesser Antilles, the centre of the heat stress has expanded southward and has affected even 

more coral regions.

02-Nov-05 The International Coral Reef Initiative has passed a Statement of Concern 

encouraging countries in the region to take immediate action to document the extent of 

bleaching, mortality, and recovery; and to target surviving coral reefs for protection.

04-Nov-05 Good and bad: corals have started to recover their color over the past 10-14 days in 

the U.S. Virgin Islands and Puerto Rico. Many Elkhorn and Staghorn (Acropora palmata and A. 

cervicornis) corals have been killed during the thermal event and disease outbreaks and lesions 

have hit bleaching-affected corals.

Coral disease appears to be spreading! Outbreaks of coral disease have been linked to periods 

of thermal stress. As such, the prevalence of disease often increases following bleaching events, 

as already stressed corals are more susceptible to infections. As temperatures return below 

stressful levels, disease progression frequently slows.

07-Nov-05 The U.S. Coral Reef Task Force has passed a resolution for its members to lead 

a coordinated interagency response to monitor the ecological and sociological impacts 

of the Caribbean bleaching; already one of the worst regional-scale events on record. The 

resolution also called for improved forecasting of thermal stress and its impacts on coral reef 

ecosystems.

11-Nov-05 In northern Colombia, bleaching ranges from partial to severe across several species, 

with water temperatures at 29°C. At Cayo Sombrero, Venezuela, the whiteness of corals has 

generally increased.
44

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

22-Nov-05 The SBA alert level for the U.S. Virgin Islands and Puerto Rico has been reduced to 

No Stress. It seems the bleaching here is finally over. The big question is whether the corals 

can recover.

28-Nov-05 Is this a case of ‘hit them while they’re down’? Outbreaks of white plague have been 

recorded in a variety of species in both the U.S. Virgin Islands and the southwest of Puerto Rico. 

The outbreaks are most intense in offshore waters where the depth is 15 m or more. Though 

the progress of the disease has slowed as temperatures have dropped, some coral deaths have 

been attributed to the disease. Black band disease has been seen in the British Virgin Islands.

01-Dec-05 The 2005 Hurricane season officially ended, with a record 26 named storms, 

including a record 13 hurricanes (5 of which were severe). This was the first time in history 

that the seasonal list of names was exhausted and the back-up Greek letter system had to be 

used.

16-Dec-05 Mixed reports; no sightings of bleaching in Bermuda; some totally bleached colonies 

at Grand Cayman Island but no mortality. At La Parguera, Puerto Rico, while most corals have 

begun to recover their color, some remain completely white and there has been high mortality 

among Elkhorn, Staghorn and Millepora corals.

21-Dec-05 Most nearshore corals in Colombia are dead, while corals 100 m offshore have 

experienced outbreaks of various diseases.

30-Dec-05 Tropical Storm Zeta has formed, missing the record of the latest ever to form by 6 

hours. It finally dissipated on 6 January 2006.

03-Jan-06 Bleaching in the Flower Garden Banks NMS is down to 10% of colonies; however, 

white plague symptoms have been observed in more than 2%.

31-Jan-06 Coral mortality levels in Martinique have hit 18%. The mortality is likely to be the 

result of an outbreak of white plague.

03-Mar-06 One up, one down. Bleaching now only affects 5% of colonies in the Flower Garden 

Banks NMS, but the incidence of white plague has risen to around 7%, with up to 20% of 

colonies infected in localized areas.

08-May-06 Are Caribbean reefs disappearing? Elkhorn (Acropora palmata) and Staghorn (A. 

cervicornis) corals will be listed as threatened species under the U.S. Endangered Species Act. 

This is the first time any coral species have been officially classed as endangered. Let’s hope we 

don’t see another year like this anytime soon.

16-Oct-06 Corals at some locations are still bleached. Most researchers have ended monitoring 

of mortality from 2005, as it has become too difficult to distinguish damage from the 2005 

warming from later stress.

Author Contacts

Jessica Morgan, Scott Heron and Mark Eakin, NOAA Coral Reef Watch, 1335 East West 

Hwy, Silver Spring MD 20910, USA. jessica.morgan@noaa.gov, scott.heron@noaa.gov and 

mark.eakin@noaa.gov.
45

Summary

zx Mass bleaching events in 1995, 1998 and 2005 have affected the reefs in the 

Mesoamerican Reef (MAR), although the 2005 bleaching resulted in little to no coral 

mortality; 

zx The 1995 event caused widespread bleaching, but minimal mortality (~10% of 

colonies had partial mortality in Belize); 

zx 1998 was the most significant bleaching event for the MAR, combined with a 

catastrophic hurricane that culminated in about 50% reduction in coral cover in 

Belize, with somewhat less in the other countries; 

zx Large-scale bleaching in late 2005 affected most reefs within the MAR, however, 

coral mortality was lower than in previous years;

zx The active 2005 storm season may have contributed to greater mixing of oceanic 

waters and minimized ‘doldrum conditions’ that were associated with the previous, 

more severe bleaching events in the MAR; 

zx Reefs in Mexico were damaged by Hurricanes Wilma and Emily, but most of the other 

2005 storms passed through the Yucatan channel into the Gulf of Mexico without 

causing substantial damage to reefs;

zx The devastating coral bleaching and hurricanes of 1998 initiated the planning for 

potential adaptation and mitigation strategies into reef management efforts;

zx The bleaching and hurricanes in 2005 may have further delayed potential recovery 

from the bleaching-related losses in 1995 and 1998; and

zx Coral cover throughout the region remains moderately low, with little to no overall 

recovery from the 1998 losses.

5. Status of the Mesoamerican Reef after

the 2005 Coral Bleaching Event

Melanie McField, Nadia Bood, Ana Fonseca, Alejandro Arrivillaga, 

Albert Franquesa Rinos and Rosa MarÍa Loreto Viruel
46

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Introduction

The 1000 km long Mesoamerican reef system (MAR) is recognized as a global conservation 

priority owing to its biodiversity, cultural and socioeconomic values. The Caribbean coast 

and cayes of Mexico, Belize, Guatemala, and Honduras contain an abundance of diverse 

and productive ecosystems including coral reefs, seagrass beds and mangrove forests that 

provide critical habitats for commercial fish stocks and many threatened species. However, 

the ecological integrity of the MAR continues to be threatened by various anthropogenic and 

natural factors, ranging from pollution, tourism and unsustainable fishing activities to recent 

global climate change. 

Map of Mesoamerican Reef Ecoregion

Bleaching and storm damage in the MAR is similar to what has happened in most reef regions 

of the world. This has changed the regulatory and management perspective, because large-scale 

coral bleaching events are beyond a local manager’s capacity to control. Identifying practical 

and effective management responses for MAR has proven very difficult; current efforts are 

focused on restoring and maintaining reef ecosystem resilience. 

Since the first mass bleaching in 1995, the MAR has suffered similar widespread bleaching 

events in 1998 and 2005. Although the 1995 mass bleaching event caused some coral mortality, 

the damage from the 1998 bleaching, combined with damage from 1998 Hurricane Mitch, 

was far more severe, resulting in a 50% average decline in live coral cover. In 2005, six sites in 

Belize were re-surveyed with the same methods, and no signs of recovery were found. There 

was no comprehensive assessment of reef recovery (or not) throughout the MAR region prior 

to the 2005 bleaching event. The limited data that are available suggest there had been little 

change from 1999 to 2005. 

11 0°W 

11 0°W 

100 ° W 90° W 

90° W 

80° W 

80° W 

13° N 13° N 

23° N 23° N 

0 170 340 680 

Kilometers

UNITED STATE S

M E X I C O

F l o r i d a 

Gulf

o f

Mexico

PACIFIC OCEA N 

GUATEMALA HONDURAS

ELSAL VADOR NICARAGUA 

COST A RICA PANAMA 

BELIZE

Rivillagige 

Islas Marias

Flower Garden Banks 

Cozumel 

Veracruz 

Banco Chincorro

Glovers 

Bay Islands

Man O War Cays 

San Blas

Miskitos 

Cays 

o 

Isla nd s 

Gulf of Californi a B a

j a C a l i f o r n i a 

LEGEND

Coral Reefs 
47

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

The 2005 Bleaching Event

The coral bleaching events of 1995, 1998 and 2005 coincided with unusually high sea surface 

temperatures and calm seas (although fewer data are available on wind speeds). The period 

between July and November, 2005 was the warmest for the Caribbean in 100 years; however 

MAR reefs were less damaged in 2005 than many other reefs in the wider Caribbean. Coral 

bleaching within the MAR was first observed in mid-July, and apparently peaked in late October 

to early November, with up to 40% of corals being affected. 

The Mesoamerican reef will likely continue to be affected by future bleaching events as sea 

temperatures are predicted to increase. However, environmental and intrinsic characteristics 

of each reef may alter the extent of resulting coral mortality or other impacts on reef resilience. 

The amount of heat stress on a specific reef is highly variable and can be influenced by local 

environmental factors (e.g. currents, wave exposure, and light penetration). Intrinsic factors, 

such as genetic make-up or heat resistance of symbiotic zooxanthellae, can also alter the heattolerance of different coral species or reefs. These inherent resiliency factors will also have 

a strong influence on which reefs are likely to survive into the future. Reef managers will 

need to apply precautionary management principles to control other stressors on the reefs, 

such as dredging operations, mangrove clearance and high density coastal developments. 

Mass bleaching has highlighted the critical need to integrate these stresses into management 

efforts. 

REEF CHECK MONITORING IN THE CARIBBEAN

As threats to reefs continue to grow, Reef Check’s community-based monitoring program 

is becoming increasingly important to document the status of the world’s coral reefs. 

Hurricanes, El Niño events, disease outbreaks, bleaching and other stresses caused by 

human activities have increased coral mortality throughout the world in the past 25 

years. Coral bleaching brought about by abnormal increases in sea temperatures is now 

considered the greatest threat to coral reefs. The most severe bleaching event to date 

occurred in 1998 and affected the entire Indo-West Pacific region. Subsequent coral 

mortality often reached 50% and, in some places, more than 90% of the hard corals were 

killed. The Caribbean region was also affected in 1998, but average mortality generally 

ranged between 5-10%. During 2005, another massive bleaching event occurred as sea 

temperatures in the Caribbean matched or even surpassed those recorded in 1998. 

Reef Check teams conducted more than 185 benthic surveys in 16 countries throughout 

the Caribbean between January 2005 and June 2006 to determine the extent of coral 

bleaching and subsequent mortality at local to regional scales. On a Caribbean-wide 

scale, the percent cover of bleached coral ranged between 2% and 62%, and bleachingrelated mortality ranged between 0% and 27%. There was little difference in the extent 

of bleaching between shallow and deep reefs and the average percent cover of live hard 

coral did not change significantly as a result of coral bleaching. 
48

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Substantial coral bleaching was recorded in Belize, Jamaica, St. Lucia and the British 

Virgin Islands. In Belize, St. Lucia and the British Virgin Islands, there was little subsequent 

mortality and no reduction in coral cover. In Jamaica, a large proportion of the corals that 

bleached subsequently died, but because the coral cover was generally low, the mortality 

did not reduce the coral cover significantly (see p 79).

If the 1998 and 2005 large-scale bleaching events are representative of a general pattern, 

then abnormally high sea temperatures within the Caribbean seem to cause extensive 

bleaching but little subsequent mortality. This is possibly a result of the recent domination 

of massive corals, which are more resilient than branching corals, within Caribbean 

coral communities, and/or because Caribbean corals are frequently exposed to larger 

fluctuations in sea temperature, allowing them to better adapt.

With greater investments in a strengthened monitoring network, the standardized survey 

methods employed by Reef Check enable the size of impacts resulting from large-scale 

environmental stresses, such as El Niño and climate change, to be quantified at local 

to global scales. Data resulting from large-scale standardized surveys are increasingly 

important in tracking reef responses to impacts from a variety of sources and are an 

extremely useful tool for coral reef management and conservation (from Cori Kane, 

ckane@reefcheck.org and Gregor Hodgson, gregorh@reefcheck.org).

Summary of results of Reef Check surveys conducted during the 2005 bleaching 

event and in the following months to June 2006, to determine the percentage cover 

of bleached coral and levels of subsequent mortality on coral reefs throughout the 

Wider Caribbean (- indicates no data).

Country Mean % Bleaching Mean % Mortality

Bahamas 16.8 -

Belize 27.9 6.5

Brazil 5.7 -

British Virgin Islands 55.0 2.1

Colombia 1.0 -

Dominica 4.6 0

Dominican Republic 26.8 -

Honduras - 14.4

Jamaica 33.7 12.5

Mexico 25.2 8.5

Netherlands Antilles - 4.2

St Lucia 43.8 4.3

St Vincent 75.0 -

US Virgin Islands 100 34.3
49

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

Belize

The longest continuous barrier reef system in the western hemisphere extends approximately 

260 km along the Belize coast, and along with the diverse assemblage of lagoonal patch reefs, 

fringing reefs, faroes and offshore atolls, covers about 1400 km2. The reefs were once considered 

to be amongst the most flourishing reefs of the Caribbean, although now the current status is 

generally comparable with the rest of the Caribbean.

Status of coral reefs prior to 2005: The combination of disturbance events and chronic 

stresses has caused a decline in live coral cover and parallel increases in macroalgae on many 

reefs. The Acropora species have suffered a dramatic reduction in live cover since the late 

1970s as a result of white band disease, and the region-wide die-off of the long-spined sea 

urchin grazer (Diadema antillarum). In 1998, the most severe coral bleaching event on record 

occurred, along with the catastrophic impacts of Hurricane Mitch that produced torrential 

rains, flooding, and destructive waves that caused considerable mechanical damage to reefs. 

The combination of bleaching, hurricane damage, and increasing chronic local stresses, has 

resulted in dramatic reductions in coral cover: 62% in southern Belize; 55% in the north; 45% 

on the atolls; and 36% on central reefs.

Long-term data exist for a few sites in Belize; live coral cover on shallow patch reefs in Glovers 

Reef atoll has decreased from 80% in 1971, to 20% in 1996, and to 13% in 1999. The inner forereef region at Carrie Bow Caye had 30-35% coral cover in the 1970s, but declined to 12-21% in 

1995. Similarly on the fore-reef at Channel Caye (3-15 m depth), an inner-shelf faroe, live coral 

declined from 85% in 1986 to 60% in 1996, primarily because of disease and loss of staghorn 

corals (Acropora cervicornis), with partial replacement by thin leaf lettuce coral (Agaricia 

tenuifolia). Subsequently, bleaching in 1998 devastated this reef, reducing coral cover to about 

5% in 1999. In 1992, the coral cover on the barrier reef off Ambergris Caye and Gallows Reef 

(near Belize City) was 25% and 20% respectively. In 1993, the coral cover on the shallow 

Mexico Rocks patch reef off Ambergris Caye was 84%, but dropped to 66% in 1995 primarily 

as a result of the 1995 coral bleaching event. Prior to 1998, most impacts on reefs in Belize 

were from diseases and hurricanes, although regional increases in nutrient concentrations 

and sedimentation, loss of Diadema, moderate over-fishing, and bleaching were also likely 

contributors. The combined impacts of mass coral bleaching and Hurricane Mitch in 1998 

exacerbated the rate of reef decline. 

Major anthropogenic threats to Belize’s reefs include coastal habitat alteration (mangrove 

clearance, dredging operations), sedimentation, agrochemical and domestic pollution (mainly 

associated with coastal development, and inadequate solid and liquid waste disposal), overfishing, and direct impacts from tourists, boat anchors and groundings. The tourism industry 

is growing rapidly, providing the impetus for many of these growing pressures. Significant 

conservation efforts have been underway for over two decades to develop a system of marine 

protected areas (MPAs) to foster reef protection. 

Effects of the 2005 Bleaching Event: The bleaching events in 1995 and 1998 caused some 

(mostly partial) coral mortality on most reefs in Belize. Sea surface temperatures (SSTs) 

surpassed the average summer maximum in both years beginning in late September in 1995 

and early September in 1998. The bleaching event of 2005, while devastating to parts of the 

Eastern Caribbean, was less severe in Belize than the 1995 or 1998 events. No coral mortality in 
50

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

ASSESSING RECOVERY OF REEFS IN BELIZE

The recovery of Belize’s reefs from the combined impacts of mass bleaching and 

Hurricane Mitch in 1998 were investigated in early 2005 to determine whether no-take 

protection status could accelerate potential recovery (i.e. increase resilience as defined 

by 4 indices: the abundance/diversity of benthic functional groups; hard coral diversity; 

coral recruitment; and herbivore abundance). Data were collected in 2005 at 3 highly 

protected sites and 3 reference sites and compared with data collected prior to or 

immediately after the 1998 event. There has been little recovery since 1998, with live 

coral cover at the 6 sites remaining less than 15%.

Because of the high level protection, it was predicted that the no-take reefs would exhibit 

significantly greater live coral cover and juvenile coral densities, and lower macroalgal 

cover than the fished reefs. However, there was no significant difference in mean live 

coral cover and coral diversity between fished and no-take reefs. Moreover, the density of 

juvenile corals was greater on fished reefs and the cover of macroalgae was significantly 

greater on unfished reefs. 

From: Nadia Bood (nbood@wwfca.org), Melanie McField (mcfield@healthyreefs.org) and 

Rich Aronson (raronson@disl.org). Coral species diversity (H')

Year

20

10

30

40

0

1997 1999 2005

Mean Unfished

Mean Fished

 Percent coral cover (300

m )

Year

1997 1999 2005

20

10

30

35

0

25

15

5

Percent macroalgae cover (300m )

Year

1997 1999 2005

0.4

0.2

0.6

0.8

0.0

1.4

1.2

1.6

1.8

1.0

Year

2001 2005

4

2

6

8

0

10

Juvenile corals per 

m

2

2 2
51

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

Belize was attributed to this 2005 bleaching event, possibly because of the relatively late onset, 

the cooling effects of numerous tropical storms and hurricanes, and possibly because many of 

the corals susceptible to bleaching had died during earlier events. Despite the lack of apparent 

bleaching related mortality in 2005, coral bleaching remains the major threat to all reefs in 

Belize; including the most remote and most well-protected (in terms of MPA management). 

While all nearshore and some offshore reefs are threatened by a variety of chronic local stresses, 

mass coral bleaching events threaten all reefs and may inhibit the natural ability of bleachingdamaged reefs to recover from repeated bleaching events.

Data from the Mesoamerican Barrier Reef System (MBRS) Project between early July and late 

September 2005 showed the first bleaching on the Belize reefs in mid July with 25% of colonies 

affected. The proportion of bleached colonies increased through August and September. 

Although no data are available for Belize after September, bleaching was observed in Belize 

(Turneffe, Ambergris Caye, Glovers Reef, among others) through to mid-November. Not all 

corals bleached and most that did were only partially bleached. Bleaching occurred primarily 

in colonies of Siderastrea siderea, Montastraea spp., Diploria spp. and Agaricia spp. 

The extent of bleaching in Belize in 2005 is seen as the number of coral colonies affected in the 

Northern Summer. Data provided by MBRS Synoptic Monitoring Program (www.mbrs.org.bz)

Location Month assessed 

(n = number of colonies)

Colonies Affected by

Bleaching (%)

Belize July (n = 488) 25

August (n = 505) 19

September (n = 221) 39

It may not be coincidental that 2005 was the most active storm season in the Western Atlantic 

in the past century. There were repetitive decreases in sea surface temperatures, which appear 

to coincide with the passage of intense storms that probably increased mixing and reduced 

SSTs. Thus, these storms may have contributed to the relatively low level of mortality of corals 

in Belize in 2005. A similar, but less dramatic, hurricane caused similar cooling during the 

1995 bleaching event. 

For four intervals between early July and mid November 2005, the average weekly SST in 

Belize exceeded the 30°C bleaching threshold for corals in the region, resulting in between 1.5 

and 3 ‘Degree Heating Weeks’ of temperature stress. On each occasion the stress was quickly 

reduced by rapid drops in temperature and coincident storm activity. By late November the 

regular cool winds, the ‘northers’, lowered sea temperatures. 

Impacts of Hurricanes in 2005: Hurricanes have had a relatively regular impact on the reefs 

of Belize, but hurricanes Hattie (1961) and Mitch (1998) were exceptional. Hurricane Hattie 

reduced live coral cover on many reefs by 80%; however reefs subsequently recovered, at least 

to some extent. Hurricane Mitch in 1998 did not make landfall in Belize, but the pounding 

waves resulted in extensive physical damage throughout Belize, particularly on the Southern 

reefs. The heavy rainfall associated with this slow-moving storm also resulted in major flooding 

that damaged both inshore and offshore reefs of Belize and Honduras. 
52

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

The numerous tropical storms and hurricanes by-passing Belize in 2005 may have benefited 

the reefs of Belize by lowering SSTs, truncating the cumulative thermal stress, and thereby 

reducing the eventual extent of coral mortality.

Status of Reefs in 2006: A comprehensive reef assessment was conducted by WWF and partners 

in summer 2006 using the Atlantic and Gulf Rapid Reef Assessment (AGRRA) protocol. This 

survey found negligible bleaching and minimal recent mortality on 141 reefs that were selected 

based on geomorphology and a randomized design using the millennium coral reef maps for 

the region. Only 207 of the 5614 colonies assessed (3.7%) showed any signs of coral bleaching. 

Interestingly, bleaching incidence was higher among fore-reef sites compared with other reef 

habitats. Disease infestation was also low overall, with less than 2% of colonies affected by any 

disease. Mean recent mortality for the 140 reefs (5614 coral colonies) was less than 1.5%, with 

no significant differences among habitats. Although the 2005 bleaching event did not cause 

significant damage to Belize’s reefs, overall live coral cover remains relatively low, averaging 

about 10% and the bleaching may have slowed recovery by 1 to 2 years. 

Fore- and pinnacle reefs were dominated by colonies of Agaricia, while Porites dominated patch 

reefs and reef flats. Mean fleshy macroalgae cover was 16% on fore-reefs, 18% on patch reefs, 

15% on reef flats and 14% on pinnacle reefs. Coral recruitment was greatest on pinnacle reefs 

(7 per m2

) followed by reef flats (4/m2), patch reefs (3/m2) and fore-reefs (3/m2). Herbivorous 

31

28

27

29

30

26

Weeks

Weekly mean % Temperature (C)

Arlene (TS)

Emily (4) Wilma 

(4)

Beta (3)

Gamma (TS)

2 DHW 3 DHW 1.5 DHW 2 DHW

Cold air mass

‘northers’ begin

June July August September October November December

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

Cindy (TD)

Dennis 

(3)

Stan (TS)

Tropical storm name (strength category) and time of occurence for 2005 storms in the Western Caribbean/MAR area.

Water temperatures provided by Smithsonian Institution’s laboratory on Carrie Bow Caye, Belize (CCRE Program)

Water temperatures in 2005 reached the bleaching threshold (around 30°C) on several occasions, 

however the passage of tropical storms in the Gulf of Mexico and Western Caribbean between June 

and December may have contributed to the series of sharp temperature declines noted in the graph 

above. 
53

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

fish (parrotfish and surgeonfish) biomass was 2.7 kg/100m2, 1.8 kg/100m2, 1.6 kg/100m2, and 

1.3 kg/100m2 on pinnacle reefs, fore-reefs, reef flats and patch reefs respectively. 

A summary of reef status in Belize in 2006 shows that the 2005 bleaching event resulted in only low 

levels of prolonged coral bleaching, disease and mortality. Data provided by WWF.

Reef Habitat 

(n = number of 

colonies assessed)

Mean Coral 

Cover (%) 

(± S.D)

Colonies 

Affected by 

Bleaching (%)

Colonies 

Affected by 

Disease (%)

Recent Colony 

Mortality (%)

Fore-Reef (n = 2295) 11 (± 4.8) 5.7 1.6 0.9

Patch Reef (n = 1348) 11.5 (± 5) 1.9 1.3 2.1

Pinnacle Reef (n = 156) 15.2 1.9 0.6 0.6

Reef Flat (n = 1815) 11.3 (± 7.1) 2.7 1.3 1.0

Socioeconomic impacts and management responses: The lives of many Belizeans are inextricably 

linked to the health of their coral reefs through their dependence on the tourism and fishing 

industries, and their need for coastal protection (low-lying coastlines). For centuries, the reefs 

have provided cultural, ecological and economic benefits as well as physical protection during 

storms and hurricanes. Belize’s growing tourism industry accounts for about 23% of the GDP 

(based on 2002 figures) with a total annual value of US$194 million. The fishing industry 

remains an important contributor with export earnings of US$67.16 million in 2005 (3.8% 

of GDP in 2005). Based on Caribbean averages, the value of shoreline protection in Belize is 

roughly estimated at US$35 to US$100 million per annum. The estimated total value of goods 

and services provided is roughly US$150 million per year (based on Belize’s proportion of 

Caribbean reefs as calculated by Reefs at Risk Caribbean). A full economic evaluation of Belize’s 

reefs will be conducted in 2007 by World Resources Institute (WRI) and WWF. 

The reefs in Belize have declined during the last decade from a generally healthy condition to 

currently having lower coral and fish abundances than other areas of the Caribbean. There are 

now many marine conservation and monitoring programs in Belize, and 18 MPAs encompassing 

about 250,000 ha. Furthermore, the increased global significance of Belize and the wider 

Mesoamerican Reef is demonstrated by the establishment of regionally focused projects and 

initiatives, including: the Mesoamerican Barrier Reef System Project, a Global Environment 

Facility (GEF)/World Bank project that is now poised to enter its second 5-year phase; WWF’s 

Mesoamerican Reef Ecoregional Program; the Nature Conservancy’s Mesoamerican Reef 

Program; the Wildlife Conservation Society’s marine program in Belize; the International Coral 

Reef Action Network (ICRAN) Mesoamerican Reef Alliance; and the Healthy Mesoamerican 

Reef Ecosystem Initiative. Since late 2003, however, national reef management efforts in Belize 

have suffered from the loss of funding and capacity within the Belize Coastal Zone Management 

Authority and Institute. 

Mexico

Reefs border the state of Quintana Roo on the east coast of the Yucatan Peninsula. The coastline 

is noted for its lack of surface rivers, although there are abundant subsurface flows within the 

limestone terrain. Coral reefs along the Mexican Caribbean coast consist of partially submerged 
54

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

fringing reefs on the northern Yucatan coast and fully developed fringing reefs, with well 

developed and extensive spur and groove systems from Xcalak to Belize. The presence of the 

Xcalak trench has fostered the development of twin reef crests and fore-reefs in this area. A 

wide carbonate shelf, influence from coastal upwelling, and scattered patch reefs characterize 

the northern section. Offshore are three banks/islands: Arrowsmith Bank, along a submerged 

platform (ranging from 25-400 m in depth) with patch reefs on its southern section; Cozumel 

Island, with reefs on the windward and leeward side; and the Banco Chinchorro atoll with 

highly developed reefs on the windward side and well developed spur and groove systems. 

Status of coral reefs prior to 2005: Puerto Morelos and nearby reefs suffered significant coral 

mortality from Hurricane Gilbert (1988) and the mass bleaching in 1995. Unlike the Belize 

reefs, the 1998 mass bleaching and Hurricane Mitch did not cause widespread coral mortality 

along the Yucatan coast. Patch reefs at Isla Mujeres and Cancun suffered some mechanical 

damage and fragmentation from Hurricane Ivan in 2004. 

These reefs have suffered from intense fishing activities since the 1960s and increasing 

pressure from tourism since the mid 1970s. Reef patches at Punta Nizuc and El Garrafon at 

Isla Mujeres have already been affected by tourism-related activities and the damage appears 

to be spreading elsewhere to Akumal, Puerto Morelos, Mahahual and Cozumel. Shallow reefs 

at Cancun, Sian Ka’an and Chinchorro have been affected by boat-related damage. The reefs 

just off the northern tip of the Yucatan Peninsula and immediately westward (Punta Mosquito, 

Boca Nueva, Piedra Corrida) have very little (<2%) live hard coral cover. 

Effects of the 2005 Bleaching Event: Coral bleaching was observed on Mahahual and Sian 

Ka’an reefs in late July by the Amigos de Sian Ka’an (Global Vision International) routine 

monitoring program. Although some bleaching was evident in almost twice as many colonies 

at Sian Ka’an compared with Mahahual, the number of colonies that were completely bleached 

at each site was low. Significant bleaching was observed during October by the Mesoamerican 

Barrier Reef System Project, with greater than 40% of colonies assessed on Xcalak reefs 

exhibiting some bleaching. 

There was significant coral bleaching along the Yucatan coast of Mexico in 2005, but subsequent 

mortality was low (from MBRS Synoptic Monitoring Program, Xcalak; Amigos de Sian Ka’an-Global 

Vision International Monitoring Program, Sian Ka’an; and UQROO, Mahahual).

Location Monitoring Timeframe 

(n = number of colonies 

assessed)

Colonies Affected by 

Bleaching (%)

Mexico (Mahahual) July-September (n = 1532) 23

Mexico (Sian Ka’an) August-September (n = 825) 42

Mexico (Xcalak) October (n = 248) 45

Impacts of Hurricanes in 2005: The Yucatan Peninsula is frequently affected by storms and 

hurricanes. In the 20th century alone, 58 hurricanes (of varied strength) have passed along 

Mexico’s Gulf and Caribbean coasts. These storms often resulted in significant reef damage from 

waves and the re-suspension of sediments. The reefs of Mexico suffered direct hurricane impacts 
55

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

in 2005, with hurricanes Emily (17 July) and Wilma (21 October) hitting Cozumel, causing 

damage mainly to shallow coral reefs (< 8 m depth), including sponges and gorgonians. 

There was a dramatic increase in bare rock substrata along Cozumel’s west coast after 

hurricanes Emily and Wilma (July and October, 2005) increasing from 10% to 40% coverage, 

as a result of the removal of sand and benthic biota. Conversely, hard coral cover decreased 

after each hurricane from 24% to 17% and eventually down to 10%. After Emily, piles of 

broken coral colonies were seen scattered around the reefs, while after Wilma the coral rubble 

was removed from the reef areas, probably because of the long duration and high intensity of 

that hurricane.

Reefs off the northern Yucatan tip were also affected. Deeper reefs sustained little damage, 

with some sedimentation increases down to 15-20 m; although the sediments were usually 

removed by currents within a few weeks. In Cancún and Puerto Morelos, impacts were mainly 

on the reef crest and primarily to branching, boulder and mound hard corals. Restoration of 

fragmented pieces was carried out shortly after for reefs within Cancún and Puerto Morelos 

Marine Parks.

Status of reefs in 2006: Minimal bleaching was observed on Mahahual and Sian Ka’an reefs 

in 2006; about 5-6% of 1858 assessed colonies were affected. The reefs seem to have recovered 

from the 2005 bleaching event, and the disease and recent mortality values were very low; 

coral cover recorded at 121 sites (n = 3113 colonies) along the Mexican Caribbean (Amigos de 

Sian Ka’an and The Nature Conservancy /WWF 2006 Rapid Reef Assessment) was unusually 

low. However, this may be related to the representative sampling design, which included many 

marginal reef sites and only a few sites with coral cover values around 20-30%.

Low levels of recently diseased or dead corals were assessed on the Quintana Roo reefs (from Isla 

Contoy to Xcalak, including Cozumel and Banco Chinchorro) in September 2005 – December 2006 

during the Amigos de Sian Ka’an and TNC/WWF Rapid Reef Assessment. 

Reef Habitat (n = number of colonies 

assessed)

Coral Cover 

(%)

Colonies Affected 

by Disease (%)

Recent Colony 

Mortality (%)

Fore-reef (n = 1886 colonies) 8 0.9 1

Reef flat (inter-tidal (n = 704 colonies) 6 0.2 0.8

Patch reef & others (n = 523 colonies) 9 1.0 0.9

Sand beaches from Punta Cancun to Punta Nizuc were lost as a result of Hurricane Wilma in 

late 2005. In February 2006, the municipality implemented a project to restore the beaches; 

however, this project resulted in the die-off of 10 species of hard corals in Punta Nizuc owing 

to erosion of the reclaimed beach areas. 

Socioeconomic impacts and management responses: Mexico’s Caribbean reefs function as 

critical fishing grounds for communities along the Quintana Roo coast. These reefs are also 

the center of tourism activities; 8 MPAs have been established to protect reefs, and there are 

new MPAs proposed, including Playa del Carmen, Akumal, Puerto Aventuras and Tulum and 

Cozumel.
56

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Guatemala

Guatemala has limited reef development along the Caribbean coast, with the best known being 

the carbonated banks of Punta Manabique, which are dominated by sediment resistant corals 

species such as Siderastrea siderea, and the isolated coral communities and diminutive patch 

reefs of the Gulf of Honduras. 

Status of coral reefs prior to 2005: There has been significant degradation of Guatemalan 

reefs because of the combined effects of hurricanes, flooding and associated sedimentation, 

and increases in sea surface temperature. The major threat to the reefs of Punta Manabique 

is sedimentation resulting from deforestation and soil erosion, which bring elevated sediment 

loads and contaminants onto reefs, causing increased coral mortality and algal proliferation. A 

study conducted in 2000, recorded live coral cover of less than 9% and non-coralline macroalgal 

cover of 65%.

Effects of the 2005 Bleaching Event: The only monitoring data on the bleaching in 2005 were 

obtained in late November at Punta Manabique with 16% of 31 colonies being affected (data 

from the Mesoamerican Barrier Reef System Project, Synoptic Monitoring Program).

Impacts of Hurricanes in 2005: Like Belize, the reefs of Guatemala were not directly affected 

by the storms or hurricanes of 2005. However, increased sediment runoff associated with the 

torrential rains generated during the passage of Hurricane Beta near Honduras is likely to have 

had an impact.

Status of reefs in 2006: Based on a rapid assessment of 5 reef sites (145 colonies) in August 

2006, the 2005 bleaching event did not appear to have made a significant impact on Guatemala’s 

bank reefs. Recent mortality was less than 1%, while disease infestation was somewhat higher 

at 11%. Mean live coral cover was low overall, averaging 8.5% and similar to that found in 

2000. Mean fleshy macroalgae cover was recorded at 7.3% and turf at 23.4%. 

Socioeconomic impacts and management responses: River inputs of nutrients and sediments 

resulting from land erosion impede reef growth. Those reefs that do exist are subjected to 

intense fishing pressure and currently have minimal fish populations. Guatemalan fishermen 

are increasing fishing pressures on the southern reefs of Belize. 

Honduras

While only small coral reef communities occur on the Caribbean coast of Honduras (Puerto 

Cortes, La Ceiba and Tujillo), there are well developed reefs on the outer Bay Islands (Utila, 

Morat, Barbareta, Roatàn, and Guanaja) and Cayos Cochinos. Well developed fringing and 

patch reefs are also found eastward (Misquitu Cays and Banks) and further northeast of the 

mainland (Swan Island). The edge of the Honduran continental shelf is almost vertical and has 

high coral cover.

Status of coral reefs prior to 2005: The Global Coral Reef Atlas reports average coral cover 

of 28% on the fore-reefs of the Bay Islands in the early 1990s. A 2001 WWF survey found 

average fore-reef live coral cover in Roatan/Barbaretta of 12%, with 8% in Cayos Cochinos, 

somewhat lower than the MAR-wide average of 15%. This same study found the prevalence of 
57

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

coral disease in Honduras was slightly higher than the MAR-wide average (4.4% versus 3.4%) 

as was recent partial mortality (1.8% versus 1.6%). The reefs of the Bay Islands were considered 

to be relatively healthy prior to the 1998 mass bleaching event and Hurricane Mitch. These 

events resulted in 18% coral mortality on shallow reefs and 14% on deep reefs, along with a 

high prevalence of coral diseases. Hurricane Mitch contributed to this damage via mechanical 

damage from waves and coral smothering from sediment-laden runoff. Hurricane Iris in 2001 

also affected Honduran reefs through increased river runoff and sedimentation. 

Effects of the 2005 Bleaching Event: No data on the extent of the 2005 bleaching event 

(during the event) were available to the authors. The MBRS Synoptic Monitoring Program 

reports data from one site (Utila) collected in February 2005 (before the bleaching season). The 

reef status indicators for 2006 show some signs of elevated disease and bleaching. However, 

without any data on the extent of bleaching during the 2005 bleaching season, no potential 

relationships can be considered. 

Impacts of Hurricanes in 2005: The 2005 tropical storms probably reduced the temperature 

of overlying reef waters and decreased the severity of bleaching and associated mortality. 

However, some reefs may have been smothered by sediment plumes from runoff and mudslides 

originating from torrential rains, especially from those generated during the passage of 

Hurricane Beta.

Status of reefs in 2006: An assessment of 61 reef sites (1363 colonies) from early June to midAugust 2006 revealed some bleaching, but less than 11%. The prevalence of coral disease was 

rather high among the reef flat and patch reef sites, but recent mortality was less than 5%. Live 

coral cover was relatively low, averaging between 10% and 15%. Mean fleshy macroalgae cover 

was recorded at 15% on fore-reefs, 16% on patch reefs and 19% on reef flats. 

There were moderate levels of coral bleaching, disease and mortality on the reefs of 

Honduras, predominantly resulting from the effects of hurricanes and to a lesser extent to 

increased water temperatures.

Reef Habitat assessed 

(n = number of colonies)

Colonies Affected 

by Bleaching (%)

Colonies Affected 

by Disease (%)

Recent Colony 

Mortality (%)

Reef flat (n = 373 colonies) 11 14 4

Fore-reef (n = 868 colonies) 4 9 2

Patch reef (n = 122 colonies) 8 18 2

Socioeconomic impacts and management responses: The Bay Islands’ reefs are the center 

for both tourism and fishing activities. Fringing reefs have been heavily exploited and the 

continued high demand for fish products has resulted in a relocation of fishing efforts to 

the more remote offshore reef banks. The Reefs at Risk project has estimated that 34% of 

Honduran reefs are threatened by anthropogenic stress, with the most pervasive being overfishing (30%), coastal developments (25%), sedimentation from agricultural practices (10%) 

and marine based activities (6%). Enforcement of regulations aimed at protecting coral reefs 

and resource management is generally weak. Twelve MPAs have been developed, although a 

number of these are not legally declared or fully managed.
58

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Mesoamerican Reef Management and Conservation Efforts

A number of regional conservation and management initiatives are being implemented to 

monitor, track, and promote the sustainable use and conservation of the MAR including: the 

Healthy Mesoamerican Reef Ecosystem Initiative; the GEF/World Bank Mesoamerica Barrier 

Reef System Project; The Nature Conservancy Mesoamerica Reef Program; and the WWF 

Mesoamerican Reef Ecoregional Program, and the ICRAN Mesoamerican Reef Alliance. There 

is relatively good collaboration among these and the many local conservation programs aimed 

at reducing threats to reefs and improving reef management. In 2006, these regional groups 

joined forces with numerous local partner organizations to conduct the largest regional 

assessment of reef health ever conducted in the region. More than 320 reef sites were surveyed 

in Mexico, Belize, Guatemala and Honduras using the 2006 AGRRA (plus) protocol. These data 

are being used for regional, national and local planning, management, and reporting efforts by 

the partner organizations.

If large-scale bleaching events continue to increase in frequency and severity, the coral 

reefs are likely to suffer further degradation. Whether these reefs will be able to maintain 

their ecological integrity will depend largely on their resilience, as well as the effectiveness 

of management efforts aimed at reducing other anthropogenic stress. Current and proposed 

bleaching management actions within the MAR are focused on identifying and protecting reefs 

that may be naturally more resistant to bleaching, have higher bleaching tolerance, and/or 

a greater ability to recover from bleaching (resilience), as well as traditional approaches for 

reducing or eliminating other anthropogenic stresses.

The areas that appear to be intrinsically resistant or resilient to bleaching can then be integrated 

within a regional MPA, which includes about 64 marine and coastal protected areas. These more 

resistant or resilient reefs may exhibit environmental (e.g. strong current or wave exposure, 

shading, etc.) or intrinsic factors (e.g. abundant heat-tolerant species) that help protect them 

from rising sea temperatures and allow them to potentially ‘reseed’ other reefs that are more 

affected by future bleaching events.

While traditional reef management efforts have focused on the management of MPAs, recent 

emphasis has been on the development of private sector partnerships aimed at promoting 

better management practices to reduce environmental impacts, particularly in tourism, 

fishing, agriculture and aquaculture industries. 

Conclusions and Recommendations 

Although the number and scope of marine conservation programs has grown tremendously 

in the last decade, continued degradation from mass coral bleaching and hurricanes has the 

potential to prevent reef recovery and even further accelerate reef damage. Climate-related 

stressors, in combination with many increasing chronic anthropogenic stressors, could lead 

to unprecedented collapse of the Mesoamerican reef ecosystem and the many livelihoods that 

depend upon it. It has been suggested that the degree to which mass bleaching will affect coral 

reefs over the long term may depend on the extent of additional environmental stressors (overfishing, pollution, habitat destruction), the degree to which corals are able to acclimate or adapt 

to the rising temperatures, the frequency of these disturbances, and whether these repeated 

disturbances compound each other. The MAR reef management community needs to increase 
59

Status of the Mesoamerican Reef after the 2005 Coral Bleaching Event

the understanding of how different coral reefs will respond to continued ocean warming. Such 

information can be incorporated into preventative strategies and aid in adaptive responses and 

monitoring. 

There was no organized and immediate bleaching monitoring response to the 2005 bleaching 

event. Most of the planned monitoring efforts (MBRS Synoptic Monitoring) occurred before 

the main effects of the bleaching event in late October. There is an urgent need to establish a 

MAR ‘Bleach Watch’ rapid response program.

A Coral Bleach Watch Rapid Response Contingency Plan for the MAR would: i) incorporate the 

NOAA ‘HotSpot’ system of forecasting bleaching events into the local managers networks; ii) 

make available early warnings of any major bleaching episode; iii) measure the spatial extent 

and severity of large scale bleaching events through all phases of the event; iv) assess ecological 

impacts of such events (8 – 10 months later); v) involve stakeholders in reef monitoring 

activities; vi) enhance communication and awareness on bleaching and the effects of climate 

change on the MAR; and vii) provide critical information necessary to evaluate implications of 

bleaching events for management, policies and strategies. 

Finally, managers need to continue to reinforce efforts to improve watershed management and 

enforcement of fishing, tourism and coastal development regulations, to reduce the stress on 

coral reefs to provide them with a better chance to recover from bleaching events.

The Healthy Mesoamerican Reef Ecosystem Initiative is a multi-institutional effort that 

generates user-friendly tools to measure the health of the Mesoamerican Reef Ecosystem, 

and delivers scientifically credible reports to improve decision-making that effectively 

sustain social and ecosystem well-being. The Initiative focuses on three over-arching 

goals: 

zx Promoting the adoption and application of eco-health and socioeconomic 

indicators by managers, policy makers and other leaders concerned with the 

integrity of the Mesoamerican Reef Ecosystem; 

zx Providing standardized analyses of reliable scientific data to improve reef 

ecosystem management; and 

zx Serving as a clearing house for information and networking among science 

and conservation partners to improve environmental management and 

stewardship of reefs.

Annual Eco-health Report Cards and triennial State of the Reef Reports will be a mainstay of 

this growing Initiative, which recently published the seminal publication, Guide to Indicators 

of Reef Health and Social Well-being in the Mesoamerican Reef Region. This publication and 

other information on the Initiative are available from www.healthyreefs.org. 
60

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Acknowledgements

The authors express their appreciation to many people who participated in the 2005 MBRS 

Synoptic Monitoring Program and the 2006 TNC/WWF Rapid Reef Assessment which provided 

data summarized in this report. This involved participants from: Honduras/Guatemala - Tourism 

Institute GoH, Utila Island, Municipal Unit (Environment Department), Fundary, Fundaeco, 

Planeta Azul, SERNA-DIBIO, PMAIB, WWF – Honduras; Belize - Belize Audubon Society, Green 

Reef Environmental Institute, Earthwatch, Wildlife Conservation Society, Friends of Nature, 

US Peace Corps, Belize Fisheries Department, TIDE, TASTE, MBRS Project, Smithsonian 

Institution, WWF-Belize; Mexico - Amigos de Sian Ka’an, TNC, Global Vision International, 

Comisión Nacional de Áreas Naturales Protegidas, SEMARNAT, Centro Ecológico Akumal. 

Author Contacts

Melanie McField, Healthy Mesoamerican Reef Initiative/ Smithsonian Institution, Belize City, 

Belize. mcfield@healthyreefs.org; Nadia Bood, WWF Mesoamerican Reef Ecoregion, Belize 

City, Belize. nbood@wwfca.org; Ana Fonseca, Centro de Investigación en Ciencias del Mar y 

Limnología (CIMAR), Universidad de Costa Rica, San José, Costa Rica. afonseca@cariari.ucr.

ac.cr; Alejandro Arrivillaga, The Nature Conservancy, Mesoamerican Reef Program, Guatemala 

City, Guatemala. aarrivillaga@tnc.org; Albert Franquesa Rinos and Rosa María Loreto Viruel, 

Amigos de Sian Ka’an, Cancún, Quintana Roo, México. afranquesa@amigosdesiankaan.org; 

rosa_loreto66@yahoo.com. 

References 

Álvarez-Filip L, Nava-Martínez G (2006). Reporte del efecto de los Huracanes Emily y Wilma 

sobre arrecifes de la costa Oeste del Parque Nacional Arrecifes de Cozumel’. Departamento 

de Monitoreo y Vinculación Científica, Parque Nacional Arrecifes de Cozumel. CONANP, 

México. January 2006.

Aronson RB, Precht WF, Macintyre IG, Murdoch TJ (2000). Coral bleach-out in Belize. Nature 

405: 36. 

Bood ND (2006). Recovery and resilience of coral assemblages on managed and unmanaged 

reefs in Belize: A long-term study. Master’s thesis. University of South Alabama. 94pp

Fonseca EAC, Arrivillaga A (2003). Coral reefs of Guatemala. In: Cortés J. Latin American Coral 

Reefs. Elsevier Science. p. 159-169.

Kramer PA, Kramer PR (2000). Ecological Status of the Mesoamerican Barrier Reef: impacts of 

Hurricane Mitch and 1998 coral bleaching. Final report to the World Bank.

McField MD (2003). Influence of disturbance on coral reef community structure in Belize. Proc 

9th International Coral Reef Symposium, Bali, Oct. 2000. Vol. 1: 63-68.

Rodríguez Z (2006). Evaluación de los hábitats pesqueros al Norte del Arrecife Mesoamericano. 

WWF. 

The Nature Conservancy (2006). Rapid Reef Assessment of Guatemala and Honduras sites in 

the MAR region towards the identification of bleaching resilient and resistant reefs. 

Technical report. MAR/TNC.

Villanueva J (2006). Fisheries Statistical Report 2005. Belize Fisheries Department. Ministry of 

Agriculture and Fisheries.
61

6. Coral Reefs of the U.S. Caribbean

The History of Massive Coral Bleaching and

other Perturbations in the Florida Keys

Introduction

The extensive offshore coral reefs (patch, offshore bank or bank barrier, transitional and deep 

reefs), fringing mangroves, seagrass meadows, and hard-bottom areas, are protected as the 

Florida Keys National Marine Sanctuary; the third largest marine protected area in the USA. 

These resources are the basis for the economically important commercial fishing and tourism 

located in south Florida, which attracts more than 4 million visitors who spend in excess of 

14 million visitor-days per year. Most are snorkelers and scuba divers, as well as recreational 

fishers and water sports enthusiasts. Others come to the Keys to relax and enjoy the tropical 

climate of a unique destination.

The waters surrounding most of the 1700 islands of the Florida Reef Tract (here called the 

Florida Keys), which are arranged in a 320 km (220 mile) arc, were designated a national 

marine sanctuary in 1990 to stem mounting threats to the health and ecological future of the 

coral reef ecosystem. More than 60% of the Sanctuary (9800 km2; 2900 square nautical miles) 

is in State of Florida waters, and the Sanctuary is managed through a co-trustee management 

agreement between the State of Florida and the national government, via the National Oceanic 

and Atmospheric Administration (NOAA). 

The Florida Reef Tract region is warmed by the Florida Current flowing from the Caribbean 

and the Loop Current from the Gulf of Mexico, enabling major reef building corals and reef 

species to inhabit such northern latitudes. The coral reef community of the Florida Keys is 

vulnerable to both natural and anthropogenic impacts, including: extreme changes in sea 

surface temperatures; coral diseases; increased sedimentation; exposure to pollution from 

the land; habitat degradation and loss resulting from coastal development; over-fishing; and 

excessive visitor use. However, the overwhelming threats to the coral reefs have been coral 

diseases and increasing sea surface temperatures (SSTs) over the past 28 years. This thermal 

stress has been exacerbated by other anthropogenic pressures on the ecosystem. 

Billy Causey
62

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

The net flow of seawater of the Florida Current is from the Gulf of Mexico and Caribbean along 

the Florida Keys. The progression of gyres rotating counter-clockwise entrains waters from Florida 

Bay and the Gulf of Mexico that influence reef areas of the Lower Keys (illustration from Tom Lee/

University of Miami, RSMAS)

History of Coral Bleaching in the Florida Keys

The first observations of massive coral bleaching in the Florida Keys were in the 1980s; these 

were associated with elevated SSTs. A combination of stress events, such as cold water stress 

from winter fronts, brief warm water events, or reduced light penetration during lengthy 

periods of turbid water, occurred in the 1970s. In 1977, an enormous die-off of the branching 

coral Acropora occurred as a result of a severe cold front that hit the Keys. These periodic 

short-term coral bleaching events reported in the 1970s were possibly preceded by similar 

episodes in the 1950s and 1960s. However, a pattern of intensifying coral bleaching and other 

marine stresses has occurred since the late 1970s.

1979: The first sign of stress on the outer coral reefs was a die-off of sponges in June-July 1979, 

with a massive loss of the barrel sponge, Xestospongia muta on Big Pine Shoal, south of Big 

Pine Key. Hundreds of large sponges disintegrated during a month when extraordinarily warm 

waters flowed from the Gulf of Mexico across the reefs. 

1980: In June-July 1980, doldrum-like weather patterns replaced the normal summer trade 

winds; the skies remained clear and almost cloudless and the seas were very calm for 6 weeks. 

Within a few weeks, angelfish, surgeonfish, butterflyfish and some other reef fish showed signs 

of extreme stress; they were respiring heavily and could be collected by hand. Open wounds and 

disease were commonly seen on the fish and large numbers began dying throughout the Keys. 

During the fish die-off, minor coral bleaching was noted on offshore coral colonies, which 

appeared mottled and lighter in color than normal. There was no uniform bleaching during 

this episode.

Florida Current

Gulf

stream

Bahamas

Yucatan

Florida Current

Loop Current

Cuba

Florida

Gulf of Mexico Circulation

Florida

Everglades

National Park

Cape

Sable

Florida 

Bay

Gulf of Mexico

Key West

Tortugas Ecological Reserve

Sand Key 

Hawk Channel

Sombrero Key

Key Largo

Carysfort Reef

Looe Key 

Florida Keys National Marine Sanctuary
63

Coral Reefs of the U.S. Caribbean

1982-1983: Elevated SSTs continued in the Florida Keys and nearby reefs. In November 

1982, coral reefs on the Pacific side of Panama were severely bleached, with considerable coral 

mortality. Record SSTs on the Pacific and Caribbean sides of Panama were thought to be the 

trigger for the massive die-off of the long-spined sea urchin, Diadema antillarum that occurred 

throughout the Wider Caribbean in 1983-84. About 95% of these important algal grazers died 

in a single year.

In July 1983, doldrum-like conditions returned to the Florida Keys at the same time the 

urchins (Diadema) were dying in what was then the Looe Key National Marine Sanctuary. The 

corals began turning white after only a couple of weeks of these conditions. This first mass 

coral bleaching spread along the seaward part of the outer coral reef tract from Big Pine Key to 

Sand Key Reef off Key West. Coral bleaching was most severe on the shallow fore-reef habitats, 

and especially on the outer shallow reefs in the lower Florida Keys where there is the greatest 

exposure to currents from the warmer waters of the Gulf and Florida Bay. In this area of the 

Keys, the net flow of water is from the Gulf, through the passes and in an offshore direction 

toward the reef tract. This current pattern bathes the coral reefs along the reef tract from Looe 

Key Reef to Sand Key with water from the Gulf and Florida Bay. 

1986: In May and June 1986, there was an alarming outbreak of black-band disease on fore-reef 

coral colonies at Looe Key Reef. Coral colonies of all sizes were affected in an area that matched 

the footprint of the 1983 mass coral bleaching event. There had been very few sightings of 

black-band disease prior to this at Looe Key Reef. However, in 1986, this disease killed coral 

colonies that were more than 200 years old. 

1987: Similar doldrum-like weather patterns re-occurred in the Florida Keys in June 1987. 

In mid-July, corals at Looe Key Reef turned mustard yellow or were mottled or pale. By 

mid-August, a mass coral bleaching event was occurring on the outer reefs of the entire Florida 

Reef Tract. In late September, there were reports of coral bleaching throughout the Caribbean. 

In mid-October, reports of coral bleaching in the Indo-west Pacific were coming in from coral 

reef managers and scientists; coral bleaching had become a global, synchronized event. 

The primary significance of the 1987 bleaching event in the Florida Keys, compared with the 

1983 event, was the broad extent of the coral bleaching along the seaward margin and on the 

outer reef tract throughout the Keys. There was also significant bleaching of corals at greater 

depths, but still restricted to the same area (outer reef tract). Corals from very shallow water 

down to depths of 30 m were almost uniformly white. This concurrence of widespread bleaching 

throughout the Caribbean and Indo-west Pacific in 1987 prompted the US Congress to hold a 

hearing in November 1987 on coral bleaching. In April 1988, a workshop on coral bleaching 

co-chaired by John Ogden and Bob Wicklund was held in St. Croix, U.S. Virgin Islands to advise 

government on potential future management action. 

1989: There was a minor coral bleaching event in August 1989. This was restricted to the 

genus Agaricia, and only on the fore-reef at Looe Key Reef. The event lasted about 6 weeks, 

and there were similar reports of Agaricia bleaching in Puerto Rico and Lee Stocking Island 

in the Bahamas. 

1990: More doldrum-like weather patterns with calm seas returned to the Florida Keys in July 

1990. Early signs of bleaching were seen in the zoanthid, Palythoa caribaeorum, which turned 
64

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

pale white, and the polyps completely closed shortly before the stony corals bleached. In early 

August, corals began to bleach on the outer reef tract starting at Looe Key Reef. By mid-August, 

there was coral bleaching on the inshore patch reefs and in the tidal passes. This was the first 

time mass coral bleaching had extended to inshore waters. The shallow coral colonies at Looe 

Key Reef were severely bleached for 2 months; their fate was followed by monitoring. There 

was a substantial loss of living coral, with more than 65% mortality of fire coral (Millepora 

complanta) on the shallow reef crest. Similar anecdotal reports came from other shallow reefs, 

from Key Largo to Key West. 

These nearshore coral reefs regularly experience higher and lower water temperatures 

than offshore corals and have acclimated over geological time to tolerate a broader range 

of temperatures. It appears that, unlike earlier mass bleaching events, SSTs during 1990 

exceeded the upper temperature thresholds of acclimated inshore coral colonies. The 1990 

coral bleaching event was significant because it was the first time that corals in nearshore 

waters had been affected by a mass bleaching episode and the first time that the large-scale loss 

of corals in the Florida Keys could be directly attributed to coral bleaching.

Although there was no mass coral bleaching in the Florida Keys between 1990 and 1997, there 

were wide-spread outbreaks of various diseases that affected both branching corals (Acropora) 

and boulder corals (Diploria, Montastraea, etc.). The Acropora species, especially elkhorn coral 

(Acropora palmata), were most affected by the outbreaks, with large amounts of living coral 

tissue killed by various diseases (e.g. white-band, white plague, white plague type II, etc.). 

There were also fish disease outbreaks in the Florida Keys and other parts of the Caribbean. The 

symptoms and species affected closely resembled the 1980 fish die-off; the disease agent was a 

fungus, Brookynella, which affects tropical reef fish during environmental stress.

1997-1998: Doldrum-like weather conditions returned to the Florida Keys in July 1997 and 

by mid-August, a mass coral bleaching event was underway. Once again, the bleaching event 

was widespread and heavily damaged the inshore corals. Third generation residents raised the 

alarm and reported to Sanctuary managers that such bleaching was unknown in the Florida 

Keys in recent history. The 1997 coral bleaching event was extensive and long-lasting, and 

affected both offshore and inshore corals, with many remaining bleached or mottled well into 

1998. Previous bleaching events had subsided by November. However, waters of the Florida 

Reef Tract did not cool much during the winter of 1997-98 and the unseasonably warm water of 

1997 continued into early 1998. The doldrum-like weather patterns started early in 1998, and 

the warm water persisted even when the wind blew, unlike previous years.

Coral bleaching in the Florida Keys and other parts of the tropical world during 1997-98 was the 

first ever back-to-back event, with local, regional and global scale damage similar to the 1987 

and 1990 episodes. Bleaching on remote Pacific islands coincided with devastating bleaching in 

the Florida Keys and the tropical North Atlantic (Wider Caribbean). The Florida Keys were then 

hit by Hurricane Georges in September 1998 and Tropical Storm Mitch, just as the bleaching 

was being assessed. In addition, there were outbreaks of the fish disease Brookynella, similar to 

1980, killing angelfish, butterflyfish and other reef species. Similar reports came in from other 

areas of the Wider Caribbean. 
65

Coral Reefs of the U.S. Caribbean

There has been an almost continual decline in coral cover in the Florida Keys in all habitats since 

1996, with a mean decrease from 11.9% cover in 1996 to 6.7% in 2005. The hard-bottom habitat 

usually has a low cover of isolated, small coral colonies alongside gorgonians (octocorals), sponges 

and other organisms; but this habitat makes up the largest proportion of rocky substrata within 

the Sanctuary. These data have been collected at multiple stations with 43 fixed sites along the 

Florida Keys, by the Florida Keys National Marine Sanctuary, US Environmental Protection Agency 

and NOAA since 1996, via the Coral Reef Evaluation and Monitoring Project (CREMP), which also 

involves the Florida Fish and Wildlife Research Institute and the University of Georgia. The top 

figure shows a precipitous decline in bleaching years with a leveling-off of coral cover since the 

1997-98 bleaching events and the hurricanes of 1998, 2004 and 2005. The lower graph shows the 

same precipitous decline in all coral habitat types between 1996 and following the 1997-98 bleaching 

events and subsequent coral disease outbreaks. Coral cover is higher in the patch reef areas compared 

with offshore reefs. The patch reefs have been exposed to broader ranges of sea surface temperatures, 

sediments and nutrients over a much longer timeframe i.e. centuries compared with decades (data 

from www.floridamarine.org). 

The greatest loss of coral cover has been on the shallow, spur and groove bank-reefs, where most 

diving occurs. One could speculate that the diving was the cause of this loss, but the largest 

decline has been on Carysfort Reef in the Upper Keys where dive pressure is low. However, 

diving remains on the list of cumulative stresses to coral reefs. 

The shallow offshore reefs have existed for decades within a narrow range of seasonal 

temperatures, salinity, and sedimentation. Recently, the maximum SST has often exceeded 

31oC during July and August when doldrum weather patterns set in for long periods. The 

10%

4%

2%

6%

8%

0%

96 97 98 99 00 01 02 03 04 05

12%

14%

Mean % Stony Coral Cover

25%

10%

5%

15%

20%

0%

Mean % Stony Coral Cover

96 97 98 99 00 01 02 03 04 05

Hardbottom Deep Shallow Patch
66

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

shallow reefs bleached first and remained bleached for longer, thus excessively stressing the 

coral colonies. The largest decline in coral cover occurred following 1997 and 1998; since then 

coral cover has remained low and relatively constant.

While there has been relatively little decline in coral cover since 1999, there has been little new 

coral recruitment. Thus, it appears that the same environmental and water quality problems 

that contributed as secondary stresses causing the loss of coral have also prevented recovery by 

new coral recruits. Another factor was the loss of algal grazing Diadema antillarum in 1983; 

macro-algae now cover much of the reefs preventing the settlement of new coral recruits, and 

increasing competition for space amongst various reef organisms. While there has been some 

coral recruitment, it has been insufficient to prevent the reefs from becoming increasingly 

barren of living corals.

There are more than 9000 patch reefs in the Upper Keys; these have shown the least decline in 

coral cover and are still the most extensive coral communities. The patch reefs occur in very 

turbid, shallow inshore waters of the Keys, through Hawk Channel and to the outer reefs. They 

grow in waters with the highest levels of nutrients in the Sanctuary and are seasonally exposed 

to the warm waters of the Gulf of Mexico. These waters get very cold in winter and very warm in 

summer, but the patch reefs have acclimated to the widest range of environmental conditions 

in the Florida Keys. There are 200 - 300 year old coral colonies that are unblemished from 

diseases. These are the only reefs that have shown any increase in coral cover during the last 

10 years. 

Other reef animals are also disappearing in the Florida Keys; for example, the corallimorph, 

Ricordea florida, (also known as false coral) was abundant on shallow reefs such as Looe Key 

Reef in the 1960s and 1970s, but began to disappear from Looe Key Reef in the early 1980s. 

Most of the populations had vanished from the shallow reefs by the time monitoring started 

in 1996. There are anecdotal reports that crinoids have also disappeared from the reefs. These 

Three hurricanes passed near the Florida Keys in 2005. SSTs (recorded at a SeaKeys C-Man station 

on Sombrero Reef) rose to more than 31oC in July, but the passage of Hurricanes Katrina (K), 

Rita (R) and Wilma (W) reduced elevated SSTs, alleviating the stressful conditions and resulting in 

minimal coral bleaching (image from Mark Eakin NOAA/NESDIS).
67

Coral Reefs of the U.S. Caribbean

were frequently seen on shallow reefs like Looe Key Reef in the 1960s and 1970s and were 

common at 20 to 40 m on deep reefs. A survey in September 2001 between 20 and 30 m found 

none during 6 hours in areas where crinoids were previously abundant. However, crinoids are 

still seen on the reefs in the Tortugas Ecological Reserve, to the far west of the Sanctuary, in 

waters that have been less influenced by elevated SSTs and land-based sources of pollution, 

indicating that crinoids are another group affected by higher SSTs and pollution.

2004-2005: Although elevated SSTs occurred in the Florida Keys in 2004 and 2005, there was 

only minor to patchy coral bleaching. The corals escaped the severe coral bleaching that was 

recorded throughout much of the Wider Caribbean. Both 2004 and 2005 were active hurricane 

seasons; each tropical storm reduced SSTs, by mixing the surface waters with deeper, cooler 

waters. 

Conclusions

Coral bleaching has been intensifying over the past 25 years at the local scale in the Florida 

Keys; this is consistent with other observations at regional and global scales. The pattern and 

intensity of coral bleaching events has shown a spatial and temporal expansion during this 

time, with concurrent increases in secondary impacts, such as coral diseases, loss of living 

tissue and low recruitment on the coral reefs of the Florida Keys. The shallow bank-reef habitats 

have been most severely affected, probably because they have historically existed in a narrower 

range of environmental conditions. In contrast, patch reefs, which are regularly exposed to 

elevated nutrient and sediment levels and broad seasonal fluctuations in water temperature, 

have been least affected and have retained the highest living coral cover. These corals have 

probably survived the bleaching episodes because they are better adapted to a broad range of 

physical conditions, similar to those that occur during doldrum-like weather. The mechanism 

is unclear; it is possible that natural selection has influenced their genetic composition so that 

they are able to tolerate greater fluctuations of temperature and nutrient levels, and lower light 

conditions. 

Coral reefs of the Florida Keys are affected by the same stresses damaging reefs worldwide: 

climate change; diseases; land-based sources of pollution; habitat loss and degradation; and 

over-fishing. There is no longer a debate that coral bleaching is linked to global climate change; 

and a few people debate the causes of global climate change. Irrespective, coral reef scientists 

and managers need to take every possible immediate action to preserve and conserve the coral 

reef resources of the world. While such scientific debate is healthy and part of the scientific 

process, there comes a time when debate seeking second opinion distracts from the obvious, 

and provides decision-makers with a no-decision option. The suspected causes for the coral 

loss in the Florida Keys have varied enormously over the years; now there is recognition that 

elevated SSTs are the primary cause of coral bleaching. A minority viewpoint has focused on 

land-based sources of pollution as the cause of coral decline. Clearly, both have played a major 

role in the decline of coral reefs on a global scale; research should be focused on unraveling the 

causes of coral decline at scales from microbial to the ecosystem.

Author Contact

Billy D. Causey, Southeast Regional Director, National Marine Sanctuary Program of USA in 

Key West, Florida; billy.causey@noaa.gov
68

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Coral Bleaching in the U.S. Virgin Islands in 2005 and 2006

Kimberly Woody, Andrea Atkinson, Randy Clark, 

Chris Jeffrey, Ian Lundgren, Jeff Miller, Mark Monaco, 

Erinn Muller, Matt Patterson, Caroline Rogers, Tyler Smith, 

Tony Spitzak, Rob Waara, Kevin Whelan, Brian Witcher and

Alexandra Wright.

Summary

zx Severe coral mortality occurred in the U.S. Virgin Islands (USVI) between July and 

November, 2005 because of bleaching and disease; the average decline in hard coral 

cover was 51.5%;

zx Sea surface temperatures exceeded the 29.5oC coral bleaching threshold for 12 weeks 

in 2005; maximum temperatures exceeded 30oC. The reefs suffered more thermal 

stress during this period than during the previous 20 years combined;

zx Coral bleaching was observed between July and November, 2005; on average it 

affected more than 90% of the coral cover;

zx Bleaching occurred in 22 coral species over a wide range of depths;

zx The greatest bleaching-related mortality occurred in the genus Agaricia; bleaching 

also severely affected Montastraea, Colpophyllia, Diploria and Porites, but mortality 

in these species was usually the result of subsequent infection by white plague or 

white syndrome; 

zx Coral losses in late summer 2005 were more severe than any time in the last 40 

years. 

Introduction

The first indications of potential thermal stress to the corals of the USVI occurred in July 2005 

with observations of bleached corals, and in August when satellite information provided by the 

National Environmental Satellite, Data, and Information Service (NESDIS) Coral Reef Watch 

indicated that sea surface temperatures (SSTs) in the north-eastern Caribbean were higher 

than normal. Temperatures continued to rise, producing more thermal stress during this 

single period than during the previous 20 years combined (Coral Reef Watch 2005, accessed 

19 November 2007). The bleaching threshold of 29.5°C (83.3°F) was exceeded for about 12 

weeks prior to 12 November 2005, with SSTs reaching just over 30°C; a full degree warmer 

than the previous year. This chapter discusses how monitoring efforts in the USVI captured the 

bleaching event of 2005 and demonstrates that several methods used to monitor the health of 

the reefs arrived at the same conclusion: coral cover on USVI reefs is declining. 
69

Coral Reefs of the U.S. Caribbean

Sea surface temperatures (SSTs) in 2005 exceeded those of 2004, especially between August and 

November (solid line) when they exceeded the coral bleaching threshold of 29.5°C in the USVI (dashed 

line). The accumulation of ‘Degree Heating Weeks’ (DHW) is shown along the X-axis in red along 

with the timing of bleaching watches and warnings issued in 2004 and the major alerts in 2005 

from August to November. The thermal condition is categorized according to the five bleaching alert 

levels defined by Coral Reef Watch’s Satellite Bleaching Alert. Source: http://coralreefwatch.noaa.gov/

satellite/current/sst_dhw_series_usvirgin_cur.html

Effects of the 2005 Bleaching Event

Declines in coral cover and increases in macroalgae resulting from a variety of stresses including 

hurricanes and coral disease have been reported previously in the USVI. For example, major 

coral losses occurred in the 1970s and 1980s as a result of white band disease, killing more than 

90% of Acropora cervicornis and A. palmata colonies, the primary shallow water reef building 

corals. However, the 51.5% decline in mean coral cover during the 12 months following the 

major 2005/06 bleaching and disease event was unprecedented. These losses occurred on well 

developed ‘high’ coral cover, high coral diversity reefs being monitored by the National Parks 

Service. Even deep reefs with high coral cover (>30% cover, >30 m) were affected by bleaching 

and disease.

National Park Service Inventory and Monitoring (NPS I&M) and US Geological Survey (USGS) 

scientists documented the effects of the 2005 bleaching and subsequent coral disease at longterm monitoring sites around St. John and St. Croix. An average of 90% of the coral cover 

bleached at 5 permanent sites (100 transects at depths between 4 m and 19 m) in St. John 

and St. Croix, including Virgin Islands National Park (VINP) and Buck Island Reef National 

Monument (BIRMN). By late 2005, many of the corals began to regain color; but then became 

infected by the white plague coral disease. In just one year, the average decline in coral cover 

at these sites was 51.5% (range 34.1% - 61.8%). There were massive declines in the major 

reef building coral species: the Montastraea annularis (complex) once comprised 80% of 

the total coral cover, but suffered a 51% decline compared with pre-2005 levels; the cover of 

Agaricia agaricites, Colpophyllia natans and Porites porites declined by 87%, 78%, and 48% 

respectively. However, there was no change in cover of M. cavernosa. While mortality of A. 

agaricites was directly attributable to bleaching, mortality in nearly all other coral species 
70

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

resulted from subsequent infection of white plague disease. The average number of species per 

transect also declined by 21%.

Agency Region Category % Bleaching % Mortality

NPS I&M / 

USGS 

St. Croix, 

St. John

Overall 90 51.5

A. agaricites 87

C. natans 78

M. annularis 

(complex)

51

P. porites 48

NPS / USGS St. Croix,

 St. John

Agaricia spp. 87*

C. natans 35*

Diploria spp. 17*

M. annularis 

(complex) 12/55*

P. porites 15*

UVI Region-wide Overall 57 40

Montastraea reef - 

total loss

70-90

Montastraea reef – 

Montastraea loss 83-95

BB / NPS St. Croix October 53

December 28

USGS VINP A. palmata 15/36

NPS BIRNM A. palmata 79.8 58.1

Summary of results of surveys conducted by several agencies (explained in the text) to determine 

the impacts of the 2005 bleaching / disease event in USVI. * indicates that percentages have been 

calculated as the proportion of the total number of colonies of each coral species surveyed. All other 

percentages have been calculated from coral cover data. Where two values are separated by /, the first 

value reports the percentage cover or proportion of colonies that suffered complete mortality, and the 

second reports the percentage of partial mortality.

The fate of 4153 coral colonies on the 100 transects was tracked by NPS and USGS. Colonies 

of Agaricia spp. were the most severely affected by bleaching with 87% mortality, and 35% of 

C. natans, 17% of Diploria spp. and 15% of P. porites colonies had died within 6 months of the 

peak bleaching in September 2005. The M. annularis (complex) initially exhibited substantial 

recovery from bleaching, but subsequently, there was high mortality as a result of white plague 

coral disease, with 12% of colonies dying completely and about 55% showing partial colony 

mortality. 
71

Coral Reefs of the U.S. Caribbean

Bleaching and mortality in territorial waters followed a similar pattern to that observed within 

the national parks. Researchers from the University of the Virgin Islands reported an average 

of 57% of the coral cover bleaching (74% of individual colonies) at a range of depths, which 

resulted in only a 4% decline in coral cover. However, there was a subsequent increase in 

tissue-eroding white syndrome, from 0.5% of colonies infected prior to and during bleaching, 

to 4% after the bleaching. This was probably responsible for a 40% decline in coral cover 

across the territory. In two deep (20-30 m) areas that formerly had high Montastraea cover 

(~36%), there was a 70-90% decline in total coral cover, resulting predominantly from the loss 

of Montastraea (83-95% cover loss). 

At 30 m depth along this Montastraea reef system, NCCOS/Biogeography Branch (BB) and NPS 

recorded a significant decrease in average coral cover between 2005 and 2006, from 8.69% (± 

1.6) in 2005 to 6.60% (± 1.3) in 2006, representing a 24% decline in coral cover. The difference 

between this estimate and the 70-90% decline described above is most likely explained by 

the patchy spatial distribution of corals along this reef system and differences in sampling 

techniques. The overall conclusion is that coral cover declined significantly between 2005 and 

2006.

In October 2005, the BB and NPS BIRMN observed bleaching in 22 scleractinian coral species 

in north-eastern St. Croix, with nearly 53% of the coral cover bleached at 91 of 94 randomly 

selected sites (depth range 3-28 m). The average coral cover at these sites was 5.6%. Bleaching 

was widespread, with no obvious spatial pattern. Coral species most affected by the bleaching 

event included D. labyrinthiformis, Agaricia spp., Mycetophyllia spp., and M. annularis. By 

December 2005, bleaching was still evident, with colonies at 15 of 18 randomly selected sites 

still bleached. Only 28% of the 3.9% total coral cover was bleached, and an additional 4% 

colonized by cyanobacteria or other algae (i.e. recently dead), but there was evidence of corals 

recovering from bleaching. 

The first time that bleached A. palmata colonies had been observed in the USVI was in July 2005, 

with 50% of 460 colonies in VINP, St. John showing some bleaching. This eventually resulted in 

36% (± 7.4) of colonies suffering partial mortality and 15% (± 8.5) dying completely. Mortality 

of A. palmata rose during 2005, but was not always directly related to bleaching. Isolated 

incidences of disease and bleaching contributed to the rise in mortality. Bleaching was not 

followed by severe outbreaks of disease except at one site, Hawksnest Bay, where a combination 

of disease and bleaching caused greater mortality within 3 months than other stresses (e.g. 

predation, physical damage) had caused during the previous 2.5 years. All surviving colonies 

regained normal coloration by February 2006. 

There was also extensive bleaching of A. palmata in 2005 at BIRMN, St. Croix. Bleaching was 

observed between August 2005 and January 2006, with greatest bleaching recorded at South 

Forereef in November 2005, where 79.8% (± 9.1) tissue bleached, followed by 58.1% (± 9.8) 

tissue mortality. The greatest tissue mortality (66.4% (± 8.7)), occurred at the Underwater 

Trail. There was 36.4% (± 12.5) tissue mortality at the North Bar. Colonies on the back-reef 

appeared to be more affected than colonies elsewhere, raising the possibility that reduced water 

flow and calmer conditions exacerbated the bleaching and resulted in greater mortality.
72

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Conclusion

The coral bleaching/disease event of 2005 added to the historical impacts of other stresses 

(pollution, over-fishing, physical damage), resulting in major damage to the reefs of the 

USVI. Management actions to improve water quality, prevent over-fishing and reduce physical 

damage and overuse may create a foundation for better reef recovery and long-term survival. 

Author Contacts

NOAA’s Center for Coastal Monitoring and Assessment, Biogeography Branch: Kimberly Woody, 

Kimberly.Woody@noaa.gov; Randy Clark, Randy.Clark@noaa.gov; Chris Jeffrey, Chris.Jeffrey@

noaa.gov; Mark Monaco, Mark.Monaco@noaa.gov. National Park Service, South Florida/

Caribbean Network: Andrea Atkinson, Andrea_Atkinson@nps.gov; Jeff Miller, William_J_

Miller@nps.gov; Matt Patterson, Matt_Patterson@nps.gov; Rob Waara, Rob_Waara@nps.

gov; Kevin Whelan, Kevin_R_Whelan@nps.gov; Brian Witcher, Brian_Witcher@nps.gov; 

Alexandra Wright, sasha_wright@partner.nps.gov. National Park Service, Buck Island Reef 

National Monument: Ian Lundgren, Ian_Lundgren@nps.gov. US Geological Survey: Erinn 

Muller, emuller@fit.edu; Caroline Rogers, Caroline_Rogers@usgs.gov; Tony Spitzack, Tony_

Spitzack@usgs.gov. University of the Virgin Islands: Tyler Smith, TSmith@uvi.edu. 

References

Coral Reef Watch. NOAA Satellite and Information Service. 2005. Accessed 19 November 2007. 

http://coralreefwatch.noaa.gov/caribbean2005/. 

Herzlieb S, Kadison E, Blondeau J, Nemeth RS (2006). Comparative assessment of coral reef 

systems located along the insular platform south of St. Thomas, US Virgin Islands 

and the relative effects of natural and human impacts. Proc 10th Int Coral Reef Symp, 

Okinawa. 4-2:1144-1151.

Jeffrey C, Clark R, Woody K, Menza C, Caldow C, Kendall M, Monaco M (2005). Coral bleaching 

and recovery observed at Buck Island, St. Croix, US Virgin Islands, October and December, 

2005. http://ccma.nos.noaa.gov/products/biogeography/coral_bleaching/welcome.html. 

Accessed 20 November 2007.

Lundgren I, Hillis-Starr Z (2007) (in review). Variation in Acropora palmata bleaching across 

benthic zones at Buck Island Reef National Monument (St. Croix, USVI) during the 2005 

bleaching event. Bulletin of Marine Science.

Menza C, Kendall M, Rogers C, Miller J (2007). A Deep Reef in Deep Trouble. Continental Shelf 

Research 27:2224-2230.

Miller J, Waara R, Muller E, Rogers C (2006). Coral bleaching and disease combine to cause 

extensive mortality on reefs in the US Virgin Islands. Coral Reefs 25:418.

Muller E, Rogers C, Spitzack A, van Woesik R (2007). Water temperature influences disease 

prevalence and severity on Acropora palmata (Lamarck) at Hawksnest Bay, St. John, US 

Virgin Islands. Coral Reefs. DOI 10. 1007/s00338-007-0310-2. 

Rogers CS, Miller J, Muller E, (and 22 others) (2007). Ecology of coral reefs in the US Virgin 

Islands. In Regal B and Dodge R (eds), Coral Reefs of the USA. 2007. Springer, in press.

Whelan, KRT, Miller J, Sanchez O, Patterson M (2007). Impact of the 2005 coral bleaching 

event on Porites porites and Colpophyllia natans at Tektite Reef, US Virgin Islands. 

Coral Reefs 26:689-693.
73

Summary

zx The effects of bleaching and hurricanes on coral reefs in 2005 varied across the 

region and within countries. 

zx Some countries experienced intense widespread coral bleaching down to 35 m, while 

the effects of increased water temperatures were moderate to low in others. 

zx Coral mortality rates were low on average; most corals recovered quickly when water 

temperatures dropped. 

zx Greater human and financial resources are needed to monitor and effectively combat 

the effects of natural disasters. 

zx Regular monitoring and analysis of data are essential components of sound 

management strategies for sustainable environmental management and economic 

growth. 

Introduction

Coral bleaching during the hot summer of 2005 hit the reefs of the Northern Caribbean 

(Bahamas, Bermuda, Cayman Islands, Cuba, Dominican Republic, Haiti, Jamaica, Turks and 

Caicos) just as they were recovering from many damaging stresses of the past 30 years. In the 

1970s, the coral reefs generally had more than 50% coral cover, with large stands of branching 

corals; Acropora palmata on the reef crest, and A. cervicornis on the shallow fore-reef slopes. 

The first signs of over-fishing of groupers and large parrotfish were evident, but the reefs were 

predominantly healthy.

The Northern Caribbean reefs were degraded during the 1980s by outbreaks of coral diseases 

(especially white band disease of Acropora), mass mortality of the main algal grazer Diadema, 

nutrient and sediment pollution from activities on land, and severe coral bleaching and 

damaging hurricanes. Coral cover in most places dropped to 5-10%, and was replaced by fleshy 

and calcareous macro-algae, with cover often 50-80%. Since then, these Caribbean reefs have 

7. The Effects of Coral Bleaching in the

Northern Caribbean and Western Atlantic

Loureene Jones, Pedro M Alcolado, Yuself Cala, Dorka CobiÁn, 

Vania Coelho, Aylem HernÁndez, Ross Jones, Jennie Mallela and

Carrie Manfrino
74

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

been slowly recovering, however, coral cover was still low and the threats from increasing 

human populations and economic pressures continued to grow. 

The first warning of problems came from NOAA in late May 2005 that indicated ‘HotSpots’ 

developing in the Northern Caribbean, especially around the Virgin Islands. These warnings 

alerted the scientists and NGOs in the region to examine their reefs in more detail. The results 

of subsequent surveys of bleaching and mortality in each country are summarized below.

Map of the Northern Caribbean region.

Ecological and Socioeconomic Impacts of Coral Bleaching and Hurricanes

in 2005

Bahamas

Geographic Distribution and Extent of Coral Reefs: The Bahamas contain 13 major islands 

and more than 2000 smaller islands or cays, distributed over 260,000 km2 on 2 large, shallow 

banks (Great Bahama Bank and Little Bahama Bank) separated by depths exceeding 4000 m. 

They are aligned northwest to southeast for more than 1400 km, from near Florida almost to 

Haiti. Coral reefs fringe most of the north and east windward coasts and bank edges and cover 

1832 km2

 of the Great Bahama Bank and 324 km2 of the Little Bahama Bank. Andros Island 

is the largest island with the third longest barrier reef system in the world (229 km). Reef 

development in the Bahamas is limited by hurricanes in exposed regions, cold winters in the 

northern Bahamas and by turbid, hypersaline waters on the leeward bank margins.

80°W 

80°W 

70°W 

70°W 

23°N 23°N 

02 11 0 20 44 0 

Kilometers 

UNITED

STATE S

CUBA

BAHAMA S 

PUERTO R ICO

F l o r i d a 

Gulf

of

Mexico

Caribbean Sea 

N ORTH ATLANTIC

OCEA N 

DOMINICAN REPUBLIC 

HAITI 

JAMAIC A 

Cayman Islands 

TURKS and CAICOS I slands

BERMUD A 

Grand C ayman 

Li

San Salvador

Havana 

Sabana Camaguey

Guacanayabo 

Batabano

Guanahacabibes Turks Bank 

Gonave 

Jaragua 

British Virgin

Islands

US Virgin 

Islands Pedro Cays 

Morant Cays 

ttle Cayman 

Isla de Pinos 

Grand 

Bahama 

Is

Andros I s 

LEGEND

Coral Reefs 
75

The Effects of Coral Bleaching in the Northern Caribbean and Western Atlantic

Status of coral reefs prior to 2005: Prior to 2005, live coral cover in the Bahamas was highly 

variable between sites, with cover ranging between 1% at Lindsay Reef at 4 m depth to 47% 

at Strip Reef at 10 m.

Impacts of Coral Bleaching in 2005: Reef Check conducted one survey at Turtle Rocks in 

August 2005 during the coral bleaching episode. This survey determined that live coral cover 

was 14%; 17% of coral colonies were affected by bleaching; and bleached colonies exhibited 

bleaching over 25-50% of their surface. No recently killed coral was recorded during the 

survey and a subsequent survey conducted in August 2006 recorded live hard coral cover 

of 18%, indicating that the 2005 bleaching event caused little or no coral mortality in the 

Bahamas.

Bermuda

Geographic Distribution and Extent of Coral Reefs: Bermuda is an isolated island chain 920 

km off the coast of North Carolina on the Bermuda Platform. Together with the Challenger and 

Argus Banks, they occupy about 900 km2

. The fringing, bank-barrier and lagoonal patch reefs 

form the most northerly coral reef system in the Atlantic and are supported by warm water 

eddies from the nearby Gulf Stream. Coral diversity is, however, limited by cool winters.

Status of coral reefs prior to 2005: There has been little change in these coral reefs, which are 

the most northerly reefs of the region (Latitude 32°20’N), during the 10 years to 2005. Coral 

cover remained at 20% around the rim, 10-15% on lagoon patch reefs, and 45-50% on terrace 

reefs. There are healthy herbivorous fish populations, and the reefs escaped serious impacts 

caused by coral bleaching that damaged reefs to the south in 2005. A comparison with the first 

surveys 25 years ago illustrates the stability: hard coral cover on the terraces - 52.4% in 1981 

vs 54.0% in 2005; and 22.5% in 1981 on outer rim coral-algal reefs vs 24% in 2005. Much of 

the stability on Bermudan reefs could be the result of a predominance of slow growing massive 

growth forms (Diploria, Montastraea and Porites species) and few branching and bleaching 

sensitive corals like Acropora.

Impacts of Coral Bleaching in 2005: Some coral bleaching was observed on Bermudan reefs 

in 1988, 1991, 1992, 1995, 1998 and 2003, however, only the 1988 and 2003 events were 

recorded in detail. In 2005, seawater temperatures peaked at 30.3°C in mid to late August at 

most locations, except at 10-15 m depth on the terrace reef sites, which peaked at 28.7°C in 

early September. All sites cooled with the passage of tropical storm Philippe. Thus, seawater 

temperatures during 2005 were not unusual compared with previous summers and no 

widespread bleaching or disease of corals was observed. Hard coral cover was 22.7% in 2005; 

the same as 2004 and a slight increase on the 14 year mean (20.8%). Black-band disease and 

white plague on Diploria, Montastraea and Porites astreoides are the most common diseases 

in Bermuda, and occur mostly on the outer rim and lagoonal patch reefs. Yellow blotch disease 

is also relatively common in Montastraea franksii. 

Impacts of Hurricanes in 2005: In 2005, there were 3 tropical storms (‘Franklin’, ‘Harvey’ and 

‘Philippe’) and 2 hurricanes (‘Nate’ and ‘Wilma’) near Bermuda. However, peak wind speeds 

did not exceed 90 km/h (i.e. generally less than regular winter storms). The major effects of 

these storms were to temporarily lower seawater temperatures by 1-2°C, with no significant 

damage to the coral reefs.
76

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Cayman Islands

Geographic Distribution and Extent of Coral Reefs: The Cayman Islands contain 3 individual 

islands (Grand Cayman, Little Cayman and Cayman Brac) on the Cayman Ridge, which extends 

from southeast Cuba to the Bay of Honduras. They are flanked to the south by the 6000 m 

deep Cayman Trench. These low-lying limestone platforms with narrow island shelves support 

prolific coral reefs. There is little obvious human impact on the coral reefs surrounding Little 

Cayman, which is the smallest and least developed of the 3 Cayman Islands. Thus, Little 

Cayman could provide a reference site for coral research in the central Caribbean.

Status of coral reefs prior to 2005: On Grand Cayman, mean coral cover declined from 25.7% 

in 1997 to 15.4% in 2001, probably because of bleaching events, lethal coral diseases and algal 

overgrowth. Increases in the abundance of algae in coastal waters near the more populated 

parts of the islands appear to have resulted from nutrient pollution leaching from resorts and 

residential areas. Atlantic and Gulf Rapid Reef Assessment (AGRRA) surveys of 18 fore-reef 

sites around Little Cayman showed a major loss in coral cover of nearly 40% (declining from 

26.3% to 15.8%) from 1999 to 2004. There has been no further decline since.

The reefs continue to support relatively diverse and abundant fish assemblages. Previous 

conservation regulations did not prevent over-fishing of high value species such as conch, 

lobster and grouper, and there was little protection of grouper spawning grounds and 

turtle nesting sites from coastal development. The relevant regulations have been recently 

amended.

Impacts of Coral Bleaching in 2005: In August 2005, corals at all sites around Little Cayman 

showed signs of bleaching and there were also colonies infected with coral disease at 6 of 

the 8 study sites. Coral cover ranged between 9% and 22% (avg. 12.9%), and the amount of 

bleached coral in 2005 was the highest ever recorded. Dichocoenia stoksii was totally bleached, 

and partial bleaching was recorded in most colonies of Montastraea faveolata, M. annularis, 

M. franksii, Agaricia agaricites, Siderastrea siderea, Diploria strigosa, and Porites porites. 

Live hard coral cover did not decline in 2006, indicating that most corals had recovered from 

bleaching stress and there was little coral mortality.

Five coral genera, Montastraea, Agaricia, Diploria, Porites, and Siderastrea dominate Cayman 

Island reefs, and comprise more than 90% of all corals found. Between 1999 and 2005, 

Montastraea decreased in density by 30% (from 46% to 32%), Porites increased by 50% 

(11.8% to 17.7%) and Agaricia rose by 15% (22% to 25.4%). Average mortality rose from 

29.0% to 42.7% for Montastraea, which was much greater than the average for all genera over 

those years (23.4% to 28.3%). The main cause of Montastraea loss appears to be white plague 

disease; this is serious because the massive frame-builder Montastraea usually dominates forereef spur and groove formations in the Caribbean. Despite these declines, coral recruitment on 

Little Cayman reefs has not declined, which demonstrates that these reefs have the capacity to 

recover; offering some hope for the future.

Impacts of Hurricanes in 2005: Several hurricanes passed within 150 km of Little Cayman in 

the last 40 years: ‘Allen’ 1980; ‘Gilbert’ 1988; ‘Mitch’ 1998; and ‘Ivan’ 2004. Hurricane ‘Dennis’ 

in 2005 passed between Little Cayman and Cuba and caused minimal damage. However, 

Hurricane ‘Ivan’ passed south of Little Cayman and made a direct landfall on Grand Cayman 
77

The Effects of Coral Bleaching in the Northern Caribbean and Western Atlantic

on 12 September, 2004. Large masses of sand piled up on back-reef corals and in lagoons on 

the south side of Little Cayman. By November 2004, there was little obvious damage on the 

fore-reef slopes. 

Cuba 

Geographic Distribution and Extent of Coral Reefs: The main island of Cuba, the Isle of Youth 

and 4195 cays and islets are distributed over 110,860 km2. The islands are at the entrance of 

the Gulf of Mexico, between the Atlantic Ocean and the Caribbean Sea. Numerous fringing 

and bank-barrier reefs border more than 98% of Cuba’s 3200 km shelf margin, although more 

than 50% are separated from the mainland by cays or by broad, shallow lagoons with many 

patch reefs. This separation has provided the outer reefs with protection from anthropogenic 

influences, except for fishing and, in some places, tourist diving. Reef crests in Cuba tend 

to be more abundant at the edge of the 4 broad sections of the Cuban shelf: the Golfo de 

Guanahacabibes (Northwest Cuba); Archipiélago Sabana-Camagüey (central north); Golfo de 

Ana María-Guacanayabo (southeast); and Golfo de Batabanó (southwest). The narrow shelf 

of the Northeast also has well developed reef crests. Inshore patch reefs are dispersed on the 

northwest (Golfo of Guanahacabibes), southwest (Golfo de Batabanó) and southeast (Golfo de 

Ana María-Guacanayabo) where there are unique reefs on muddy substrata. There are 2 barrier 

reefs: Archipiélago Los Colorados (NW Cuba); and Archipiélago Jardines de la Reina. 

Status of coral reefs prior to 2005: Live coral cover averaged 21% on Cuban reef crests and 

shallow reefs and 18% on fore-reefs. The corals have been stressed by organic and chemical 

pollution around populated areas, diseases, the Diadema die-off and resultant competition 

with algae, and some earlier bleaching. The reefs were recovering from these stresses until 

2005, when bleaching and hurricanes resulted in coral mortality.

Impacts of Coral Bleaching in 2005: In summer 2005, coral bleaching was widespread 

and intense. Assessments conducted by the Early Warning Coral Reef Volunteer Monitoring 

Network showed that coral bleaching around Cuba varied from 1-10% to 75-100% of colonies, 

predominantly between categories 50-75% and 75-100% (at 89% of reported sites). Only one 

site, Punta Francés (SW of Isla de la Juventud), suffered lower intensity bleaching (1-30%). 

Most anecdotal reports refer to a high degree of recovery by May 2006. 

Impacts of Coral Bleaching in 2006: Coral bleaching in 2006 was widespread but with varying 

intensities, increasing after mid-September. The volunteer monitoring network reported that 

coral bleaching did not exceed 10% and was generally not higher than 5%. María la Gorda was 

an exception with 10-30% colonies bleached at 20-25 m depth, but much less in shallower 

areas. Warming increased in mid-September, and moderate bleaching (10-30%) was recorded 

at Havana City and Jardines de la Reina Archipelago, and intense bleaching (75-100%) at Punta 

Francés (SW Isla de la Juventud). Bleaching was low in the Sabana-Camagüey Archipelago and 

Bahía de Cochinos. No information is available from Santiago de Cuba and Granma provinces, 

to the east. 

Impacts of Hurricanes in 2005: Hurricane Denis, which made landfall in July, 2005 

near Punta del Inglés, caused only minor damage at Cabo Cruz and Pilón (Nacional Park 

Desembarco del Granma, south-eastern Cuba), despite wind velocities reaching 310 km/h. 
78

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

The reef was not exposed to the direct force of the wind and waves and only a few colonies of 

Acropora palmata (<10%) were fragmented. However, at Pilón (to the east), the impact was 

much greater because of its windward position. Many sponges and gorgonians were damaged, 

corals suffered fewer losses and sand was removed from the beaches.

In October, 2005, Hurricane Wilma produced wind velocities of 70-90 km/h, with gusts to 

110-120 km/h, and 4-5 m waves at La Bajada-Uvero Quemado-María la Gorda (Ensenada de 

Corrientes, western Cuba). Many hard coral colonies and gorgonians in shallow water (<6 m) 

were removed. Damage was significantly less in the spur and groove zone (10-12 m), with 

only a few hard coral colonies fragmented or overturned. The sea-urchin Diadema antillarum 

disappeared in places where it had been abundant. Approximately 10-15% of hard coral 

colonies were bleached after the hurricane.

Wilma caused damage to coral reefs near Havana City, down to depths of 15 m; many sponges 

and gorgonians were deposited onshore and a few Acropora palmata colonies were overturned 

or fragmented. Massive corals were less affected; but the recovering Diadema population was 

devastated. However, seagrass beds and mangroves behind reef crests suffered only minor 

damage. 

Socioeconomic impacts and management responses: In spite of current economical 

constraints, Cuba is still devoting much effort to coral reef assessment, research and 

monitoring, through different research projects and scientific-technical services. Since 1995, 

tertiary treatment for sewage generated by all tourist developments has been compulsory. 

These requirements are implemented and enforced through recently established EIA and 

licensing processes (Resolution No. 168/95 of Environmental Impact Assessment). Recent 

water quality assessments show that pollution from tourist resorts is negligible. In addition, 

destruction of coastal areas has been prohibited through the establishment Decree-Law 

212 (year 2000) of Coastal Zone Management. Since then, there has been no additional 

anthropogenic destruction of the largely undisturbed mangroves.

Dominican Republic

Geographic Distribution and Extent of Coral Reefs: The Dominican Republic has 1576 km 

of coast including the islands of Saona, Catalina, Beata and the Cayos Siete Hermanos, with 

coral reefs along 166 km and mangroves along 377 km. The longest reef (64.2 km) is to the 

northwest of Montecristi. Most of these are fringing reefs, but there are also 2 barrier reefs, 

numerous patch reefs, and 4 large offshore banks. On the east and northwest coasts, there 

are broad coastal shallow platforms with barrier reefs. In most other places, high turbidity 

prevents reefs from forming.

Status of coral reefs prior to 2005: CARICOMP data show that coral cover rose from 8.2% in 

2000 to 11.5% in 2001 and Reef Check surveys showed mean coral cover of 19.4% at Bayahibe 

in 2004. 

Impacts of Coral Bleaching in 2005: Reef Check surveys recorded significant bleaching at 

all sites surveyed during September/October 2005. Bleaching affected as much as 68% of live 

corals, with the majority of colonies being entirely bleached. The average mortality was 11% 

across all sites surveyed, but there was great variation between sites with mortality ranging 
79

The Effects of Coral Bleaching in the Northern Caribbean and Western Atlantic

between 0% and 38%. Significant bleaching also occurred between late May and the end 

of August 2006, with bleaching affecting between 66% and 85% of living coral cover and 

individual colonies exhibiting bleaching over 50-95% of their surface areas.

Jamaica

Geographic Distribution and Extent of Coral Reefs: Jamaica is the 3rd largest Caribbean 

island; 230 km long by 80 km wide with 891 km of coastline and a coral reef area of 1240 

km2

. Well developed fringing reefs occur along most of the north and east coasts, while patchy 

fringing reefs grow on the broader shelf of the south coast. Reefs and corals also grow on the 

neighboring banks of the Pedro Cays, 70 km to the south, and the Morant Cays, 50 km to the 

southwest.

Status of coral reefs prior to 2005: Hard coral cover declined from 50% in the 1970s to less 

than 5% by the early 1990s as a result of hurricanes, Diadema die-off, coral diseases, and 

over-fishing. Coral cover has risen to 10-15% recently, with some sites having coral cover of 

34-46%. Fish populations in Jamaica have been declining for decades because of poor fishing 

practices. Reef Check surveys at 35 sites between 2001 and 2006 reported an average density 

of 9.8 fish per 100 m2

.

Impacts of Coral Bleaching in 2005: Between August and October 2005, there were prolonged 

high sea surface temperatures around Jamaica and nearby countries, with 5 to 6 weeks of 

greater than normal temperatures, which resulted in widespread bleaching. This was first 

observed on the north coast from late August to early September and on the south coast in 

late September to early October. Corals started recovering as early as February/March when 

sea temperatures began to cool.

Bleaching was assessed 26 times at 16 sites. Variation in the proportion of corals bleached 

ranged from 10% to 95%, with Montastraea annularis, M. faveolata, M. cavernosa, Siderastrea 

siderea, Diploria strigosa, Agaricia spp., Millepora complanata and Porites porites being most 

commonly affected. Within five months, about 50% of the bleached corals had recovered. 

There were however, increases in recently killed coral and fleshy algae, which usually indicate 

nutrient pollution.

In September 2006, black-band and white plague diseases were noted in the Port Royal Cays, 

especially Lime Cay and South-east Cay. White plague has been the most prevalent disease 

since January 2006, affecting the massive corals Siderastrea, Montastraea, and Diploria 

species.

Impacts of Hurricanes in 2005: Major hurricanes that have damaged Jamaica’s reefs include 

‘Allen’ in 1980, ‘Gilbert’ in 1988 and ‘Ivan’ in 2004. The hurricanes in 2004 and 2005 passed to 

the south of Jamaica causing most damage to south coast reefs. Hurricane Ivan passed parallel 

to the south coast in September 2004 causing damage to Port Royal and Portland Bight Cays, 

with large numbers of fractured and killed branching corals in shallow water (2-8 m). Other 

nearby corals were turned over, relocated, abraded and bleached. Some survived virtually 

undamaged or with only partial mortality. The lesions caused during the hurricane were 

quickly being overgrown by fast growing opportunistic algae; however, by February, 2005, 
80

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Site

0

5

10

15

20

25

30

35

40

NIA – Nov 2005 NIA – May 2006 RKC – May 2006

Mean % Cover

Dman's Cay

Gun Cay

Lime Cay

Monkey Island

Rackhams Cay

Tern Cay

Wreck Reef

RKC – Nov 2006

0

5

10

15

20

25

30

Dairy Bull

Dancing Lady

Dman's Cay 1

Dman's Cay 2

Gun Cay 1

Gun Cay 2

Lime Cay 1

Lime Cay 2

Monkey Island 1

Monkey Island 2

Mooring One 1

Mooring One 2

Navy Island 1

Navy Island 2

Pear Tree 1

Pear Tree 2

Rackhams Cay 1

Rackhams Cay 2

Rio Bueno

Tern Cay 1

Tern Cay 2

Wreck Reef 1

Wreck Reef 2

Site

 % Cover

% Cover of Hard Coral % Cover of Bleached Coral

Comparison of the percent cover of nutrient indicating algae (NIA) and recently killed coral (RKC) 

recorded during surveys in November 2005 and May 2006.

Live hard coral cover (light bars) ranged from 3.1% to 28.1% (average 13.4%). At some sites on 

Lime Cay, Drunkenman’s Cay and Dairy Bull, more than 80% of the coral community bleached 

(dark bars). 
81

The Effects of Coral Bleaching in the Northern Caribbean and Western Atlantic

some of the corals displayed evidence of recovery and growth. In 2005, Hurricanes ‘Dennis’, 

‘Emily’ and ‘Wilma’ passed close to the island bringing heavy rainfall and wind. Although 

the island was not affected directly by either of these systems, the southern parishes and the 

western town of Negril were hit by storm surge that toppled some corals.

Mangroves and seagrasses: The government, through the National Environment and Planning 

Agency (NEPA), has embarked on a process that will eventually lead to a no net loss policy 

for mangroves and seagrasses. Where development will result in loss or destruction, it is 

required that there is relocation/rehabilitation of an area roughly 120% the size that is lost or 

damaged.

Socioeconomic impacts and management responses: It is expected that the impacts of the 

damage associated with these events will ripple throughout the fabric of the socioeconomic 

environment in Jamaica as they have undoubtedly contributed to the continued decline in the 

landed fisheries resources of the island. Management responses have included cancelling the 

bird shooting season after hurricane Ivan to allow time for populations to recover (inclusive of 

mangrove areas).

NEPA has implemented a stricter permit and licensing system for activities that may damage 

coral reefs, and also ensured that assessments are conducted to feed into annual reports 

on resource status, with recommendations for management and improvement. A defined 

government policy on wetlands (inclusive of coral reefs, mangroves and seagrasses) is being 

planned.

The Government has implemented programs to increase the number of monitoring sites and 

the frequency of monitoring undertaken. This is facilitated by the University of the West Indies 

and the Jamaica Coral Reef Monitoring Network. 

In an effort to improve conservation efforts by the Government and the general public, the 

importance of all coastal ecosystems is continually being emphasized by demonstrating the 

economic losses that occur as a direct result of ecosystem degradation. 

Turks and Caicos Islands

Geographic Distribution and Extent of Coral Reefs: There are 8 low-lying limestone islands 

and 40 small sand cays distributed over 1736 km2 in the Turks and Caicos, which is on an 

extension of the southeastern Bahamas Platform. All the islands and cays are fringed by 

narrow, discontinuous, shelf-edge reefs dominated by corals, algae and gorgonians growing 

down to 40 m, on hard substrata.

Status of coral reefs prior to 2005: Reef condition across the islands was quite similar, 

although human pressures from fishing, boat grounding, diving/snorkeling, sediments 

and nutrient flows from coastal development, varied between islands. Live coral cover on 

Providenciales ranged from 6–36%, with extremely low macro-algal cover. The near shore 

patch reefs had many isolated coral heads of Montastraea and Diploria, and a high cover of 

gorgonians. Montastraea, Siderastrea and Porites were the dominant corals on South Caicos. 

The cover of macro-algae at South Caicos was generally higher and this is probably related to 
82

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

greater fishing activity and localized eutrophication. The Grand Turk reefs were generally in 

good condition, with 24% average coral cover (range 17-33%) and high coral diversity that 

was dominated by Montastraea annularis, M. cavernosa, Siderastrea siderea and Agaricia 

agaricites, with many gorgonians and low algal cover (1-20%). However, the average coral 

cover at 5 major dive sites decreased from 32.4% in 1995 to 21.9% in 2004. 

There were active domestic and export fisheries, especially for queen conch (Strombus gigas), 

spiny lobster (Panulirus argus), grouper, hogfish and snappers. Herbivores, such as parrotfish 

and surgeonfish, are usually not kept. Most fishing is done with hand lines but there were a few 

traps. Generally, fishing pressure was relatively low and fish communities were relatively intact 

on both the Turks and Caicos Banks, with potential yields assessed by AGRRA of 70–140 kg per 

km2

 with an average fish density of 2-14 fish per 100 m2 for selected families (Pomacanthidae, 

Cheatodontidae, Balistidae, Acanthuridae, Haemulidae, Lutjanidae, Serranidae and Scaridae). 

Fishermen have reported little change in the past 5 years.

Impacts of Coral Bleaching in 2005: The first coral bleaching occurred on South Caicos 

between September and December 2005. Of 166 coral colonies at The Warhead, The Fishbowl 

and Tuckers Reefs, only 3 colonies (1 Montastraea annularis and 2 Agaricia agaricites) 

were completely bleached, and 87 colonies showed partial bleaching. In shallow water (<6 

m), bleaching was seen in colonies of Acropora cervicornis M. annularis, Stephanocoenia 

intersepta, A. agaricites, Montastraea cavernosa and Diploria labyrinthiformis. At 10 m, 

colonies of M. annularis, A. agaricites, Porites porites, and Porites astreoides were bleached, 

while at 15 m there was bleaching in colonies of M. annularis, A. agaricites and Siderastrea 

siderea. 

Coral colonies appeared to be recovering in December 2006, with little evidence of coral 

mortality. The Department for Environmental and Coastal Resources initiated coral bleaching 

surveys to follow progress as some black-band disease was evident on South Caicos, similar 

to previous years. 

Conclusions and Recommendations

The increased frequency and incidence of intense hurricanes coupled with abnormal rising 

sea temperatures are now common annual dilemmas facing the Node countries. Coastal 

ecosystems are now stressed more frequently and as such have less time to recover before the 

next catastrophe.

All countries continue to face similar problems of infrastructure related to funding and human 

resources. In the face of these difficulties, they are still committed to achieving environmental 

health by implementing monitoring and conservation exercises. All are still trying to achieve 

a balance between conservation and economic growth and have employed several measures to 

achieve this, such as integrated coastal zone management. The process is still being hampered 

in some cases by outdated laws and fines, and because some governments are still sacrificing 

the environment in their bid to achieve economic growth. To halt the continued degradation 

of the region’s natural resources, outdated legislation and fines need to be revised. More 

monitoring is also required, but to achieve this, the lack of trained personnel available to 

conduct assessments needs to be addressed. 
83

The Effects of Coral Bleaching in the Northern Caribbean and Western Atlantic

Author Contacts

Loureene Jones, National Environment and Planning Agency, Kingston, Jamaica, loureene@

gmail.com; Pedro Alcolado, Instituto de Oceanología, Ciudad de la Habana, Cuba, alcolado@

ama.cu; Yuself Cala, Parque Nacional Desembarco del Granma, Cuba; Dorka Cobián, Parque 

Nacional Guanahacabibes, Cuba; Vania Coelho, Central Caribbean Marine Institute, Princeton, 

New Jersey USA, vcoelho@dominican.edu; Aylem Hernández, Centro Nacional de Áreas 

Protegidas, Cuba; Ross Jones, Bermuda Institute of Ocean Sciences (BIOS), Ferry Reach, St. 

George’s, Bermuda, Ross.Jones@bbsr.edu; Jennie Mallela, Department of Life Sciences, The 

University of the West Indies, St. Augustine, JMallela@fsa.uwi.tt; Carrie Manfrino, Central 

Caribbean Marine Institute, Princeton, New Jersey USA. manfrino@reefresearch.org.

References

Jones, LA (2006). An assessment of hurricane damage in Negril: A review and critical analysis 

of the Reef Check methodology of assessing reefs. MSc thesis, University of the West 

Indies, Mona, Jamaica.

Jones R (2006). Bermuda Institute of Ocean Sciences – Marine Environmental Program 

(MEP), Annual report to the Department of Environmental Protection (Ministry of the 

Environment) 2005-2006. 129 p.

Woodley JD, Chornesky EA, Clifford PA, Jackson JBC, Kaufman LS, Knowlton N, Lang JC, 

Pearson MP, Porter JW, Rooney MC, Rylaarsdam KW, Tunnicliffe VJ, Wahle CM, Wulff 

JL, Curtis ASG, Dallmeyer MD, Jupp BP, Koehl MAR, Neigel J, Sides EM (1981). 

Hurricane Allen’s impact on Jamaican coral reefs. Science 214:749–755.
85

Summary

zx During summer 2005, a persistent ‘HotSpot’ surrounded these islands; 

zx Coral bleaching and mortality was probably the most severe ever recorded in the 

Lesser Antilles and was the most extreme for the wider Caribbean during 2005; 

zx The most severe bleaching event ever recorded at Barbados occurred during 

September and October 2005, and affected all coral species at all depths, and all reef 

types and habitats;

zx There was between 25% and 52% mortality of corals in the French West Indies, 

especially at Guadeloupe and Martinique. Bleaching affected most coral species and 

resulted in reduced larval recruitment in the following 2 seasons. However, there 

appears to be no effects on fish populations;

zx There was extensive bleaching (80%) on the northern Netherlands Antilles islands of 

St. Maarten, Saba, and St. Eustatius in August 2005; but only minor bleaching and 

minimal mortality on the southern islands of Bonaire and Curaçao;

zx On the island of Tobago, most species bleached, with 66% average cover of bleached 

coral. Bleaching in Montastraea annularis was highly variable; there was 73% 

bleaching in one stand, but only 6% in another, on Buccoo Reef;

zx No hurricanes passed through this region in 2005; this partially explains the severity 

of bleaching as there were no strong winds to lower seawater temperatures;

zx These islands are highly dependent on their coral reefs, thus there is an urgent need 

for appropriate management responses as sea temperatures are predicted to rise 

further in future.

8. Status of Coral Reefs of the Lesser Antilles

after the 2005 Coral Bleaching Event

Claude Bouchon, Pedro Portillo, Yolande Bouchon-Navaro,

Louis Max, Paul Hoetjes, Angelique Brathwaite, Ramon Roach, 

Hazel Oxenford, Shay O’Farrell and Owen Day
86

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

The French West Indies

Introduction

The French West Indies (FWI) in the Lesser Antilles lie between 14°20’ and 18°00’ N and consist 

of the islands of Martinique, the Guadeloupe Archipelago (with Guadeloupe, La Désirade, 

Marie-Galante and Les Saintes islands), St. Barthélémy, and the French part of St. Martin/St. 

Marteen. The population in these islands was 834,000 people in 2004, including about 2500 

registered fishers.

Guadeloupe and Martinique are volcanic and mountainous islands, situated roughly in the 

centre of the West Indies and surrounded by a narrow island shelf that receives high levels of 

volcanic sediments. Corals grow on the rocky surfaces and form fringing reefs on the eastern 

sides. These reefs are especially important for tourism; 665,000 tourists visited Guadeloupe in 

2005 and 381,000 visited Martinique in 2004. Thus tourism is a major economic contributor 

in the FWI with hotel capacity of Guadeloupe and Martinique exceeding 13,000 rooms and 

additional accommodation available in small-scale rural cottages. The most common marine 

tourist activities are glass-bottom boat tours, kayaking, water skiing, surfing, sailboat rentals, 

sport fishing and particularly scuba diving. There are 40 scuba diving clubs in Guadeloupe and 

a similar number in Martinique, with diving focused on the Caribbean (leeward) coasts. For 

example, about 100,000 divers visit the Îlets Pigeon in Guadeloupe each year.

70°W 

70°W 

60°W 

60°W 

13°N 13°N 

0 1 65 30 26 0 

Kilometers 

VENEZUEL A

Caribbean Se a 

BARBADOS

ST. VINCENT and the GRENADINES

GRENADA 

To bago TRINIDAD and TOBAGO

ST. LUCIA 

Tr inidad

MARTINIQUE

DOMINICA

GUADELOUPE MONTSERRAT 

ANTIGUA and ST KIT TS BARBUDA -NEVI S 

ANGUILLA

LESSER ANTILLES NETHERANDS ANTILLES

Golfo de Honduras

LEGEND

Coral Reefs 

British Virgin 

Islands

US Virgin 

Islands

Curacao Bonaire 

Aruba

Los Roques

Isla Margarita 

St Maarten

St Barthelemy 

Grande-Terre

Basse-Terre

Saba St Eustatius

DOMINICAN 

REPUBLIC PUERTO RICO

Map of the Lesser Antilles region.
87

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

A mix of fringing and barrier reefs grow on the narrow shelves surrounding Guadeloupe and 

Martinique. These are similar to reefs growing around high islands in the Eastern Caribbean 

States with better development on the windward coasts of the islands, but greater biodiversity 

on the protected leeward coasts. There are 4 marine reserves: 2 in Guadeloupe; 1 each in St. 

Barthélemy and St. Martin; and 9 no-take zones in Guadeloupe and Martinique. 

Saint-Barthélemy and Saint-Martin are the northern-most islands in the FWI, situated on a 

shallow, sediment covered shoal. Saint-Barthélemy is surrounded by numerous small islands, 

and Saint-Martin/Sint-Maarten is under French and Dutch control. There are poorly developed 

fringing reefs and extensive seagrass beds around both islands, and large areas of mangroves 

have been destroyed by land reclamation.

Status of Coral Reefs Prior to 2005

There is very clear evidence of coastal ecosystem degradation throughout the FWI, which 

has affected coral reefs, seagrass beds and mangroves. Long-term monitoring since 1999 

has shown that the coral communities of Guadeloupe and Martinique have been degraded, 

particularly during the last 7 years, confirming qualitative observations since the early 

1980s. High rainfall, deforestation for agriculture, poorly managed coastal development and 

mangrove clearing have resulted in excessive sediments and nutrients flowing into coastal 

waters, especially into enclosed bays and lagoons. Elevated nutrient loads from overuse of 

fertilizers and poor wastewater treatment have fueled the proliferation of algae, particularly 

Sargassum and Turbinaria on the exposed outer slopes on the Atlantic coasts, and Dictyota on 

more sheltered areas in lagoons and reefs on the Caribbean coasts. Turbinaria and Sargassum 

are highly resistant to waves generated by hurricanes, whereas Dictyota is removed by each 

passing hurricane, although it recolonizes reefs rapidly after storms. Chronic over-fishing has 

reduced fish stocks, particularly herbivorous fish that control algal communities. 

Previous coral bleaching from elevated sea surface temperatures (SST) during El Niño years in 

1984 and 1987 was relatively minor. The first significant bleaching occurred in September and 

October 1998, when the SSTs exceeded 29°C for several weeks. There was extensive bleaching 

of hard corals, actinarians, zoantharians and gorgonians. Although these reefs suffered some 

mortality among certain corals, the effects of bleaching in the FWI were relatively small 

compared with other regions in the Caribbean. Bleaching occurred again in 1999 in Guadeloupe, 

but the effects of bleaching were obscured by damage caused by Hurricane Lenny. FWI reefs 

show chronic but minor bleaching almost every year in September when SSTs exceed 29o

C for 

a short period.

The waves generated by hurricanes limit coral reef growth in the Lesser Antilles, and severe 

hurricanes cause serious damage to coasts every 10 years on average. Direct physical damage to 

coral reefs occurs to 15 m depth and recovery can take years to decades. Hurricanes are usually 

accompanied by torrential rains that wash massive quantities of sediments and nutrients 

onto nearshore reefs, resulting in short-lived algal blooms. Since 1989, there have been 4 

hurricanes that have directly damaged the FWI: Hurricane Hugo (1989) hit Guadeloupe; and 

Saint-Barthélemy and Saint-Martin were damaged by Hurricanes Luis and Marilyn in 1995, 

and Lenny in 1999, which also caused damage to Guadeloupe. 
88

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Guadeloupe: The first signs of reef decline were evident in the 1980s, and by 2000, satellite 

remote sensing showed that only 15-20% of the marine habitats in Guadeloupe still had 

healthy coral communities. Coral cover varied from 15-22% on reef flats; and 24-26% on outer 

slopes before 2005. The proportion of coral colonies showing disease ranged from 23-33%, 

with the average surface area of dead tissue ranging from 27-32%. Algal turf was the dominant 

component of the benthic community, but the greatest changes were in the cover of brown 

macro-algae, which were influenced by nutrient concentrations, seasonal temperature changes 

and wave action. The increase in macro-algae was also favored by the decline in sea urchin 

populations during the early 1980s and over-fishing of herbivorous fish.

The reefs of Guadeloupe were not severely damaged by previous coral bleaching, although 

56% of corals bleached in 1998, with up to 80% of the surface area of colonies being pale. 

There was, however, little mortality except among colonies of Diploria labyrinthiformis, 

which suffered 80% mortality. Another bleaching episode that was confined to the reefs of 

Guadeloupe occurred in September 1999, affecting almost 50% of corals. Subsequent mortality 

was negligible because the passage of Hurricane Lenny in November 1999 cooled the waters 

and allowed corals to recover.

In 1989, Hurricane Hugo destroyed branching corals (Acropora palmata, A. cervicornis, 

Madracis mirabilis) on the outer reef slopes down to depths of 15 m. The A. palmata stands, 

which were prominent on the outer reef slopes, have not recovered but Madracis mirabilis has 

quickly recolonized the area. Hurricanes Luis, Marilyn and Lenny damaged Guadeloupe’s coral 

reefs more severely than Hugo, mainly because large waves up to 13 m high destroyed corals, 

sponges and gorgonians down to 25 m depth. This damage was compounded by torrential rains 

and extensive soil erosion. The high diving pressure on these reefs causes additional damage, 

particularly from inexperienced divers, especially on the Ilets Pigeon, which receives between 

80-100,000 divers annually. 

Surveys at Guadeloupe in 2000 recorded 228 fish species in 59 families, with the average fish 

density between 119 and 550 fish per 600 m2

. The highest numbers were in the protected 

area of Pigeon Island. The fish biomass in Guadeloupe and the other islands was 368 to1893 

kg. ha-1. In 2004, the average number of fish species in 600 m2 areas was 45 and the average fish 

biomass in Guadeloupe was 807 kg.ha-1, indicating that fish communities have not changed 

significantly in recent years. However, fish stocks around all the islands are over-exploited and 

large fish (groupers, snappers, parrotfish) are rarely seen. Most fishing is artisanal with 1200 

registered fishers, working from 947 fishing boats that are generally small (6-8 m long) and 

operate in inshore waters. Only 10 boats are equipped to operate offshore. There are however, 

about 1000 unregistered fishers who fish regularly. About 40,000 Caribbean traps are used, 

with many of these traps being ‘lost’ after each hurricane. However, those traps with wire or 

plastic netting continue to catch fish long after they are lost.

Martinique: Coral cover in 2004 varied between 32% and 40% on various reefs. The dominant 

cover type was algal turf followed by brown macro-algae, indicating that nutrient pollution 

from the land is affecting the marine environment. The increase in brown macro-algal cover 

is a major factor contributing to the deterioration of the reefs. The proliferation of macroalgae was first noticed on the Atlantic coast in the early 1980s, coinciding with the mass 

mortality of the herbivorous sea urchin Diadema antillarum. Since 1984, macro-algae, 

particularly Sargassum, have become abundant along the Caribbean coast, probably because 
89

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

of eutrophication resulting from urban and industrial wastes from Fort-de-France Bay and 

sediment from agriculture. In the early 1980s, Fort-de-France Bay had the highest coral 

diversity in a variety of different habitats (reefs, seagrass beds, shoals, rocky shores). However, 

increasing pollution is threatening these ecosystems and those in the nearby Baie du Marin.

Like Guadeloupe, the reefs of Martinique were not severely affected by previous bleaching events. 

In 1998, 59% of coral colonies bleached, with an average of 69% of the surface area of colonies 

being bleached. However, there was little subsequent mortality and recovery was reasonably 

rapid. There was minimal bleaching in 2003 and 2004, but no significant mortality. 

Hurricanes have caused significant damage to the coral reefs of Martinique; Hurricanes David in 

1978 and Allen in 1980 damaged Acropora palmata and A. cervicornis communities, especially 

in the Sainte-Luce region. Although there has been no major hurricane damage since then, 

these reefs have not recovered completely.

Fishing in Martinique is also primarily artisanal. At present, there are about 1300 registered 

fishers who use traps and concentrate their fishing effort on inshore reefs. There are many more 

unregistered fishers, making the total fishing population closer to 2500. The catch of pelagic 

species has risen with the introduction of anchored fish aggregating devices. There was a major 

fish kill in September 1998, which affected all trophic levels on the Atlantic coast of Martinique. 

However, there were no obvious changes in the structure of the reef fish community. Surveys 

in 2004, showed an average of 46 fish species in 600 m2 areas and an average fish biomass of 788 

kg.ha-1, indicating that no significant changes in fish communities have occurred recently.

Saint-Martin and Saint-Barthélemy: Coral cover varied in 2004 between 20% and 26%. Algal 

turf was the most abundant cover type on the reefs of Saint-Barthélemy. Brown macro-algae 

were also abundant, indicating that nutrient pollution was affecting these reefs. The reefs of 

Saint-Martin and Saint-Barthélemy have been colonized by Dictyota and Lobophora, which 

out-compete corals and other benthic invertebrates for space. Hurricane Luis caused some 

damage to the coral reefs of Saint-Martin and Saint-Barthélemy, but the most significant impact 

was caused by the re-suspension of very fine sediments from the shallow continental shelf. 

These sediments remained in suspension for several months and smothered many organisms. 

Re-suspension of sediments is probably a reason for the limited development of coral reefs on 

these islands. 

In 2004, the average number of fish species in 600 m2

 areas was 48 and the average fish biomass 

was 751 kg.ha-1. There have been no apparent changes in fish communities in recent years, 

although seasonal variations of fish biomass were noted on the reefs of Saint-Barthélemy.

The 2005 Temperature Anomaly in the French West Indies

Generally, Caribbean reef corals tolerate a maximum sea water temperature of 29°C; any 

increase above this for a long period will stress corals and induce bleaching. The severity of 

bleaching is linked to the magnitude of the temperature increase and its duration. There is 

usually some minor bleaching every September when sea temperatures reach their annual 

maximum.
90

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

This figure daily sea temperatures in Guadeloupe from March 2005 to December 2006, with consistent 

temperatures over the 29°C ‘bleaching threshold’ for almost 6 months in 2005, reaching a maximum 

of 32°C in September, and then for a short period in 2006. (24 h moving average).

Effects of the 2005 Bleaching Event

Guadeloupe: Severe coral bleaching developed in August after sea temperatures exceeded 29°C 

between May and November. Surveys in December 2005, showed that bleaching had affected 

76% of all coral species in the community; 51% of all colonies; an average of 58% of the surface 

area of affected colonies; and a 12% loss of coral cover. The density of coral recruits during this 

period was the lowest recorded, declining from a mean of 23 recruits per 10 m2 prior to 2005 

to 10 per 10 m2 in December 2005. There was also a significant drop in the number of coral 

species and colonies recruiting in 2006. 

Few corals recovered in 2006, particularly in shallow areas, and there was delayed mortality 

throughout the year despite normal sea temperatures at most reef sites. Some of this mortality 

was the result of coral diseases, but most was because of the slow death of bleached colonies 

that had not recovered their zooxanthellae symbionts. At the end of 2006, bleaching still 

affected 33% of coral species, 15% of all colonies, and an average of 21% of the cover of coral. 

The condition of surviving colonies also deteriorated in 2006, with the number of coral species 

showing coral disease increasing from 60% to 71%, while disease in colonies rose from 33% 

to 39%. The average colony surface area affected by tissue necrosis varied from 32%-49%. The 

delayed mortality resulted in a decline of live coral cover on the outer reef slopes, from between 

44% and 25% cover before bleaching, to 14% after. Simultaneously, the mean cover of algae 

rose by 15% on the outer reef slopes.

25

26

27

28

29

30

31

3-20054-20055-20056-20057-20058-20059-2005

10-2005

11-2005

12-2005

1-20062-20063-20064-20065-20066-20067-20068-20069-2006

10-2006

11-2006

12-2006
91

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

The effects of increased sea temperatures on the coral reefs of the French West Indies are presented 

in these 3 figures. There was no apparent bleaching by July 2005; but between August and December, 

there was clear evidence of a major bleaching event with about half of all corals bleached, but few 

signs of mortality. However, by mid-2006, 30% to 40% of the coral cover had died, and more than 

10% of the remaining corals were bleached.

Guadeloupe

0

10

20

30

40

50

60

70

80

90

Mar – Jul 05 Nov – Dec 05 Apr – May 06 Nov – Dec 06

Survey Date

Saint Barthélemy

0

10

20

30

40

50

60

70

Feb – 05 Aug – 05 May – 06 Nov – 06

Survey Date

Martinique

0

10

20

30

40

50

60

Jul – 05 Dec – 05 Jul – 06 Dec – 06

Survey Date

%

% Species bleached 

% Colonies bleached

%

%

% Cover bleached 

% Mortality (% cover lost)
92

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Observations in June 2007 showed that many corals remained pale or partially bleached and 

had not fully recovered their stock of zooxanthellae, despite normal seawater temperatures. 

The three-dimensional structure of the reefs was apparently not affected by the bleaching; for 

example, in 2004, the average number of fish species per 600 m2 was 45 and the average fish 

biomass was 807 kg.ha-1 and by the end of 2006, comparable measures were 48 species and 994 

kg.ha-1.

Martinique: Bleaching started in August 2005 and the first surveys in December showed that 

bleaching affected 51% of coral species, 49% of all coral colonies, and an average of 50% of the 

surface area of each colony. Coral mortality was moderate in December with a loss of 11% in 

coral cover. The number of coral recruits decreased from an average of 49 recruits per 10 m2

 in 

July 2005 to 28 recruits per 10 m2 in December 2005, even though coral recruitment is usually 

greater in December. Juvenile recruitment was still low in 2006 (32 recruits per 10 m2).

Bleaching persisted during 2006 and by the end of the year, 27% of all coral species showed 

signs of bleaching and 18% of coral colonies were affected. The average bleached surface area 

of corals was 26%. As a consequence of the delayed coral mortality, the average coral cover had 

declined from 28% to 19%. Most of the recently dead corals were colonized by algae, which 

increased cover by 15%. The health of surviving coral colonies was threatened by coral disease, 

with 49% of colonies showing tissue necrosis and 48% of the colony surface area affected. 

The fish communities did not appear to be affected: in the 2005 bleaching there was an average 

of 46 species per 600 m2 and fish biomass of 788 kg.ha-1; whereas in 2006 there were 44 species 

on average and the biomass was 1207 kg.ha-1. 

Saint-Barthélemy: Bleaching was recorded first in August 2005 and affected 63% of coral 

species, 48% of colonies, and an average of 54% of the coral cover. No immediate coral 

mortality was seen. Coral recruit density was the lowest noted during this season, declining 

from 50 recruits per 10 m2 to 35 recruits per 10 m2. Recruitment of juveniles remained low 

in 2006. Throughout 2006, there was delayed coral mortality and by the end of the year coral 

communities showed no signs of recovery, with 40% of coral species, 14% of colonies and an 

average of 20% of the surface of individual colonies still being bleached. By November, the live 

coral cover had declined by 40%, from 20% before bleaching to 12% afterwards and the dead 

corals were mainly colonized by algae, with cover increasing by 12%.

The surviving colonies deteriorated significantly throughout 2006; early in the year, tissue 

necrosis on colonies rose from 18% to 23%, and the colony surface area affected increased 

from 30% to 48%. The number of infected colonies was still high although many had died from 

coral disease. By mid-2007, many corals remained pale or partially bleached and had not totally 

recovered from bleaching, despite normal sea surface temperatures.

The average fish species richness on reefs was 48 species per 600 m2 and the fish biomass 

751 kg.ha-1 before 2005; and 57 species per 600 m2

 and a similar fish biomass of 742 kg.ha-1 in 

2006
93

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

Impacts of Hurricanes in 2005

The three island groups, Guadeloupe, Martinique, and Saint-Barthélemy and Saint-Martin 

were not affected by hurricanes in 2005. Previous hurricanes caused some damage: Iris, Luis 

and Marilyn in 1995; and Lenny in 1999.

Socioeconomic Impacts and Management Responses

In Guadeloupe, the Grand Cul-de-Sac Marin marine reserve was created in 1987 and an 

experiment to farm the branching corals Acropora palmata and A. cervicornis was initiated 

by the Université des Antilles et de la Guyane in 2005 in the lagoon. The project was achieving 

encouraging results, until the bleaching event killed all the farmed corals. This indicates that 

coral farming in an uncontrolled environment may not be a good palliative solution to coral 

repopulation. The alerts issued about potential bleaching in the MPAs resulted in increased 

surveillance and monitoring, but there was no other specific management intervention.

Conclusions - 2005 Bleaching in the French West Indies.

Coral mortality on the outer reef slopes of the FWI islands ranged between 25% and 52% at 

different reefs. The variation in mortality was primarily associated with the species composition 

of the reefs, rather than differing ecological conditions between the reef sites. Coral species 

showed a large range of bleaching responses to the increased sea temperatures, for example, 

corals of the families Agaricidae, Favidae and Mussidae were particularly susceptible to 

bleaching. There was a significant positive correlation between the delayed coral mortality seen 

and the degree of bleaching in most of the corals. However, some species that bleached rapidly 

in 2005 recovered well during 2006 e.g. the Poritidae. The hydrocoral, Millepora squarrosa, 

which was common on the reefs previously, appears to have almost disappeared from the FWI 

and no recruits were seen in 2006 and 2007. 

As the three-dimensional structure of the reefs and their capacity to provide shelter for the 

associated animals have not changed significantly as a result of the bleaching event, the 

species richness, abundance and community structure of reef fish assemblages have remained 

similar.

The Netherlands Antilles

Introduction

There are 2 distinct island groups in the Netherlands Antilles: Bonaire and Curaçao are small 

oceanic islands 70 km north of Venezuela, with continuous fringing reefs around the islands 

that are particularly well developed on the leeward sides; and St. Maarten, Saba and St. Eustatius 

are on the northern arc of the Lesser Antilles and are volcanic with steep cliffs, narrow shelves 

and limited reef development along the windward coasts. There is limited coastal development 

on St. Eustatius and Saba, thus anthropogenic effects are minimal. St. Eustatius has true 

calcareous reefs and also corals growing on the volcanic rocks. The only true reefs on Saba are 

on the eastern side of the island and most sheer walls are populated by sponges. St. Maarten, 

which is shared between the Dutch (southern portion) and the French (northern portion), 

has seen rapid population growth and unmanaged expansion of tourism such that the reefs 

have been degraded by pollution, deforestation, sedimentation, eutrophication from sewage, 

recreational boating and anchors, particularly along the south and west coasts. A submerged 

atoll with actively growing reefs, known as the Saba Bank, is also within Netherlands Antillean 

waters.
94

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Status of Coral Reefs Prior to 2005

Bonaire and Curaçao: The greatest diversity of corals are on the leeward (western) side on a 

30 m to 150 m wide terrace that slopes gently to about 12 m depth. The prominent corals are 

Acropora palmata, A. cervicornis and Montastraea annularis, with many large hard coral heads 

and a variety of gorgonians. After the drop-off at 10–15 m depth, the fore-reef slopes downwards 

at 30-60 degrees to a sediment bottom between 30 m and 50 m depth. The dominant corals are 

M. annularis, M. faveolata, and Agaricia agaricites, with M. cavernosa and Stephanocoenia 

in deeper waters. On the northern side of Bonaire at Boca Bartol and Playa Benge, the reefs 

have unusual shallow water spur and groove formations, while the southern facing shore has 

buttresses that slope steeply down to the sediment platform at 100 m depth. The reefs on Klein 

Bonaire are varied with some descending steeply close to the shore to a sediment platform at 

25-30 m depth. The reefs of Curaçao are similar although there are vertical drop-offs from 6-35 

m depth on the eastern side.

The terrace on the eastern side of Bonaire and the north-eastern side of Curaçao extends 100-

200 m offshore and to a depth of 12 m, with primarily crustose coralline algae, Sargassum, and 

some gorgonians. The leeward reef slope has less coral cover and abundant brown algae.

On Curaçao, there are about 250 fish species and 55 coral species, with an average of 19 coral 

species per 200 m2

 at 6 m depth and 23 species at 12 m. Live coral cover at most sites declined 

by 10% between 1997 and 2002, with a greater decline at 6 m depth than at 12 m. In 2002, 

coral cover at 6 m depth on the leeward side of Curaçao was 30-50%, and 30-70% at 12 m. 

Since 1983, A. cervicornis has almost disappeared because of white-band disease, except for a 

few small stands. A. palmata has also declined on both Curaçao and Bonaire. The shallow reefs 

(0-2 m depth) have completely disappeared since the early 1980s. 

There are only 20-30 commercial fishers on Bonaire, but many people fish recreationally. The 

commercial targets are mostly pelagic species (tuna, dorado, wahoo) caught with hook and 

line, although trai (throwing nets) and reda (encircling nets) are used to catch bait and big-eye 

scad respectively. Spear-fishing is illegal, but still occurs, and the use of kanasters (fish traps) is 

discouraged because of the conflicts they cause with recreational divers. In 2000, reef fish were 

abundant and diverse and biomass was high. However, in 2002, grouper, conch and lobster 

were absent from some of Bonaire’s reefs and snapper populations were declining. Parrotfish 

were still abundant because they are considered inedible. Illegal poaching of turtles also occurs, 

killing as many as 20 turtles per month. Collection for the aquarium trade is banned.

On Curaçao, there are a few hundred artisanal fishers who mostly target pelagic species. Fish 

traps and gill nets are also used and illegal spear-fishing is still practiced. Fish populations 

have been severely reduced by heavy fishing pressure; larger fish, particularly groupers and 

parrotfish, lobsters and conchs are rarely encountered. However, snappers and small parrotfish 

are still fairly common. Turtles are protected, but are occasionally caught as by-catch.

Saba: There are 35 coral species and some gorgonians, with the dominant corals being 

Montastraea anularis, M. cavernosa, and Diploria strigosa. Rough seas reduce coral cover in 

shallow waters (0-7 m) and storms in 1998 and 1999 caused major declines in the abundance 

of Acropora palmata. Coral cover does not exceed 20% because of high sediment loads and 

frequent benthic algal blooms, and massive corals are often overgrown by bioeroding sponges. 
95

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

In 1996, there were 28 coral species on the Saba Bank, with 60-90% coral cover. However, 

AGRRA surveys in December 1999 recorded only 24% coral cover with the highest cover at 21 

m depth, and 27.5% dead coral cover. This indicated that disease and bleaching had severely 

damaged these shallower reefs. 

There is limited fishing around Saba and fish populations are considered healthy, but still 

recovering from historical over-fishing. Grouper and snapper biomass continues to rise after 

the establishment of the Saba National Marine Park. About 50 fishers (mostly from Saba) fish 

on the Saba Bank targeting mainly lobsters, red snapper and conch. There was an intensive 

grouper fishery until populations declined. 

St. Eustatius: The offshore reefs begin at 25 m depth with complex spur and groove formations 

that extend to 60 m. There are steep buttresses on the northern part with 80% coral cover 

and 35 species. The northern complex has a labyrinth of encrusted ridges, sand channels and 

huge encrusted rocks, with a fringing reef on the exposed Atlantic side. The leeward side is 

mostly a sandy plateau with large populations of Queen Conch down to 17 m. Hurricanes Luis 

and Marilyn (1995) removed large amounts of sediment from the eroding cliffs and severely 

damaged soft corals and sponges; recovery was rapid.

There are only 15 full- or part-time fishers on St. Eustatius, who use traps to catch fish and 

lobsters for restaurants. Yellowtail snapper and grouper are highly prized, but locals eat 

almost any reef fish. Spear-fishing with scuba is illegal, but is still practiced. Many conch were 

collected until 2001, when regulations were enforced, but some are still taken illegally. Conch 

populations appear healthy, and turtles are protected, although some poaching of eggs still 

occurs despite an intensive public awareness campaign. 

St. Maarten: Patch reefs with spur and groove structures at 8-18 m depth are concentrated 

near the east and south-eastern part. In 1999, average hard coral cover was about 30% with 

bleaching and some diseased corals evident. Hurricane Luis damaged reefs, seagrass beds and 

beaches, and re-suspended sand smothered Acropora palmata stands in shallow water, but 

these have largely recovered.

There are about 30 fishers who use fish traps and other artisanal practices. Fish populations 

are still reasonable, although big groupers are uncommon and conch populations have been 

depleted.

Effects of the 2005 Bleaching Event

Coral bleaching was first noticed in the north on St. Maarten, Saba, and St. Eustatius in late 

August 2005 and continued until mid-November 2005. Around 80% of coral colonies were 

bleached on these islands in mid-October. Coral loss on St. Eustatius from June 2005 to June 

2006 was 18% at 15 m depth (coral cover dropped from 24% to 6%) and 11% at 25 m (from 

26% to 15%). No mortality data are available for St. Maarten and Saba.

Bleaching was less common on Bonaire and Curaçao, with bleaching affecting an average of 

14% of coral colonies during November 2005. No mortality was apparent and average coral 

cover remained at around 40% at 12 m depth and 30% at 6 m, between April 2005 and April 

2006. 
96

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

There was negligible bleaching in 2006 on St. Maarten, Saba, and St. Eustatius and in Bonaire 

and Curaçao. At Bonaire, 9% of coral colonies were partially bleached in October 2006 (normally 

the peak bleaching month) and only 2% were completely bleached. Bleaching (pale and fully 

bleached) affected only 3% of coral colonies on Curaçao, in early November 2006. 

Records of the average percentage of hard coral colonies that bleached on Curaçao during the last 10 

years show that bleaching was greatest in 1998 and 2005.

Impacts of Hurricanes in 2005

The northern islands of St. Maarten, St. Eustatius and Saba are regularly hit by hurricanes, 

whereas Bonaire and Curaçao are south of the path of most Caribbean hurricanes and are only 

rarely damaged. Thus, the reefs of Bonaire and Curaçao are extremely well developed with 

very old and large coral heads. The last hurricane damage occurred in 1999 when Hurricane 

Lenny generated 6 m high waves that struck the lee side of the islands, particularly Bonaire, 

completely destroying many shallow reef areas to depths of 6 m. In some areas, broken coral 

heads rolled down the reef slopes causing serious damage at greater depths. In 2004, Hurricane 

Ivan caused minor damage, but Bonaire and Curaçao were not affected by hurricanes in 2005.

There was no serious hurricane damage during 2005 on St. Maarten, St. Eustatius or Saba, 

where regular hurricanes have meant that optimum reef development occurs in deeper 

waters. 

Socioeconomic Impacts and Management Responses

No special management responses resulted from the events of 2005, except that monitoring 

and surveillance were increased in the MPAs, e.g. in the Bonaire Marine Park, the Curaçao 

Marine Park, the Saba National Marine Park, and the St. Eustatius Marine Park. In 2006, nature 

conservation legislation was passed in St. Maarten to provide legal designation of the St. Maarten 

Marine Park. This will include the levying of a diver fee, and will enable the well-established 

local NGO (St. Maarten Nature Foundation) to manage the intended marine park. Ten years of 

funding has already been donated by WWF and other Dutch donors to help management until 

it becomes financially self sufficient. The NGO employs a park manager and assistant manager 

to establish moorings, conduct monitoring, and undertake outreach activities.

0

5

10

15

20

25

30

35

Survey Date

% Bleaching

May-97

Oct-97

Feb-98

May-98

Nov-98

Feb-99

May-99

Sep-99

Jan-00

Apr-00

Aug-00

Dec-00

Apr-01

Nov-01

Apr-02

Nov-02

Oct-03

Apr-04

Dec-04

Apr-05

Nov-05

Apr-06

Nov-06
97

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

Barbados

Introduction

Barbados is the most easterly of the Lesser Antilles island chain. The uplifted fossil coral 

island is surrounded by a 2-3 km wide shelf that supports a variety of coral reefs. Fringing 

reefs distinguish the west (leeward) coast and make up 8.4% of the mapped reefs; beyond that 

there is an almost continuous bank reef parallel to the north, west and south coasts 0.5 to 1.2 

km offshore. The crest of this bank reef is 5-35 m deep in the north, west and south and is 

shallower along the more exposed southeast coast, where it becomes a bank barrier reef. This 

bank contains 87.1% of the mapped reefs. There are also a few patch reefs at 5-16 m depth 

between the shore and the bank reef, along the west to southeast coasts.

Status of Coral Reefs Prior to 2005

The inshore fringing reefs have been affected by poor water quality caused by coastal construction, 

tourism infrastructure and inland agriculture; by storms; and by over-exploitation of fish and 

corals. Average live coral cover is about 10% in the seaward spur and groove zone (range 

1-30%). The offshore bank reefs are relatively undamaged with about 30% coral cover along 

the crest. These bank reefs are far enough offshore to escape damage from poor water quality, 

and are also less accessible to fishers. The patch reefs are more variable; they are dominated 

by hard corals and sponges on the west coast, and soft corals on the more exposed windward 

coasts, although hard coral cover averages 25%. There have been infrequent bleaching events 

in south-eastern Caribbean islands; most have occurred within the last decade but were usually 

of low to moderate intensity. 

Effects of the 2005 Bleaching Event

NOAA satellite sea surface temperature (SST) data for the eastern Caribbean, including Barbados, 

showed a coral bleaching ‘HotSpot’ (SSTs in excess of 1oC above the maximum expected 

temperatures) that developed to the northeast of Barbados in early June, and strengthened in 

June-July to cover Barbados and the Lesser Antilles by early August. The HotSpot strengthened 

during August and September and covered much of the Caribbean Sea by early October. It 

finally disappeared in late October.

Sea temperatures at 8 m depth on a shallow patch reef confirmed the satellite data, with 

daily mean temperatures climbing steadily from 28.6o

C in late June to more than 30oC in late 

August and early September. This was 1-2oC above the ‘typical’ summer maximum. During the 

second and third weeks of September, strong currents brought cooler water onto the reefs and 

reduced temperatures by almost 1.5oC, before they returned again to 30oC for the last week of 

September. Sea temperatures declined to 29.3oC by the end of October and to 28.6oC by the 

end of November. Benthic temperature loggers at 20 m depth on other sites showed similar 

temperature patterns to those reported by research divers and dive operators, with widespread 

warm waters extending to at least 30 m depth.
98

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

An automatic temperature recorder placed on Batts Rock in 2005 showed that water temperatures 

rose above the normal bleaching threshold of 29oC in mid-year and continued until late October. 

Additional temperature recorders paced at North Bellairs, Coconut Court and Atlantis showed that 

these sites had a similar temperature profile to that of Batts Rock, with a characteristic decline 

of almost 1.5oC during the second and third weeks of September caused by strong currents that 

brought cooler water onto the reefs before returning again to 30o

C in the last week of September. Such 

prolonged hot water stress had never been recorded previously in Barbados.

The accumulated heating stress was severe for the eastern Caribbean including Barbados, with 

Degree Heating Weeks (DHWs) exceeding 5 for much of the summer and reaching a maximum 

of 13-14 weeks by the end of October and beginning of November 2005.

The first bleached corals were noticed on 24 August at Batts Rock (8 m depth), where several 

colonies of Siderastrea siderea were a pale mauve/blue color. Two days later, similar bleaching of 

S. siderea was seen at 16-20 m depth on the Atlantis bank reef, as well as colonies of Meandrina 

meandrites and the fire corals (Millepora spp.). By 3 September, bleaching affected colonies 

of Dendrogyra cylindrus and Porites astreoides, and some colonies of Montastraea annularis. 

By mid-September there was widespread bleaching of whole coral colonies in all reef habitats 

on the west and southwest coasts of Barbados. Dive operators, charter boat captains, fishers 

and the public reported bleaching. Surveys of 6 reef habitats between mid-September and 

October 2005 showed severe coral bleaching in all reef habitats, with 59-86% of all hard coral 

colonies showing some bleaching. Inshore reefs were more severely affected (80.6% of colonies 

bleached) than offshore reefs (60.5%). 

Bleaching also affected 90% of the 29 coral species, with some species being more vulnerable 

than others. Among the more common species, the most susceptible to bleaching were D. 

cylindrus, Agaricia spp., Favia fragum and Millepora complanata, with 90% or more of 

colonies affected, whereas fewer than 10% of colonies of Colpophyllia natans and Madracis 

decactis bleached. More colonies of Diploria strigosa and P. astreoides bleached on shallow 

reefs than on deeper reefs, while the converse was true for S. siderea.

Batts Rock

27.50

28.00

28.50

29.00

29.50

30.00

30.50

Date

Temperature ( C)

28/6/05

5/7/05

12/7/0519/7/0526/7/05

2/8/059/8/05

16/8/0523/8/0530/8/05

6/9/05

13/9/0520/9/0527/9/054/10/05

11/10/05

18/10/0525/10/05

1/11/058/11/05

15/11/0522/11/05

o
99

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

The proportion (%) of colonies of the more abundant hard coral species (10 or more colonies 

observed) that bleached in 2005. Data were collected at 6 reefs around Barbados during Sept/Oct 

2005. Abbreviated family names: Ag – Agariciidae, As – Astrocoeniidae, Ca – Caryophylliidae, Poc – 

Pocilloporidae, Sid – Siderastreidae (Adapted from Oxenford et al. 2007).

This table summarizes the affects of bleaching from late September 2005 to February 2006, at 6 sites 

around Barbados that have been monitored regularly. Most species and a majority of colonies showed 

bleaching in shallow and deep water. Live cover estimates are from on-going monitoring at adjacent 

sites at the time of the survey (adapted from Oxenford et al.

Site, Reef type & 

Location (depth m)

GPS 

coordinate

Survey 

date

Coral species 

bleached 

of total per 

100m2

Total no. 

colonies 

(100m2)

Mean % 

colonies 

bleached 

(SE)

Survey 

date

Mean % 

colonies 

bleached 

(SE) 

% 

Live 

coral 

cover

Batts Rock, Patch 

West Coast (8)

N 13o08’08 

W 59o38’18

15-Sep 15/20 791 73.8 

(6.8)

7-Feb 46.0 

(1.7) 29.9

Maycocks, Bank 

West Coast (22)

N 13o17’32 

W 59o

39’47

23 Sep 14/16 409 59.1 9-Feb 32.6 

(2.7) 37.8

Atlantis, Bank West 

Coast (16-20)

N 13o07’18 

W 59o38’55

30-Sep 15/17 445 63.0 

(3.8)

7-Feb 43.7 

(6.7) 34

North Bellairs, 

Fringing West Coast 

(3-5)

N 13o11’18 

W 59o38’31

4-Oct 14/17 1629 82.0 

(3.1)

9-Feb 39.7 

(8.7) 23.3

Welcome Inn, Bank 

Southwest Coast 

(15)

N 13o

03’35 

W 59o33’25

5-Oct 20/21 621 59.4 

(6.9)

6-Feb 43.1 

(3.0) 22.9

Coconut Court, 

Patch Southwest 

Coast (5-6)

N 13o

04’24 

W 59o36’11

6-Oct 15/16 713 86.0 

(1.3)

6-Feb 19.9 

(1.5) 25.8

Overall 26/29 4608 70.6 

(4.8)

37.5 

(2.5) 28.9

0

20

40

60

80

100

AgAgaricia spp.

AsS. intersepta CaE. fastigiata

Faviidae

F. fragum

D. strigosa

M. Complex

M. cavernosa

D.labyrinthiformis

C. natans

Meandrinidae D. cylindrus M. meandrites D. stokesii

Poc M. mirabilis M. decactis Poritidae P. porites P. astreoides

SidS. radians S. siderea Milleporidae M. complanata M. alcicornis M. squarrosa

% Bleached

Species

2005 2006
100

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

The bleaching event developed rapidly and simultaneously on deep and shallow reefs on both 

the west and southwest coasts of the island. The first signs of bleaching in the most susceptible 

species appeared when SSTs rose above 30oC for more than 1 week. As the length of exposure 

increased, virtually all hard coral species eventually bleached, regardless of whether they were 

on degraded inshore or healthy offshore reefs. This demonstrated that elevated SSTs can cause 

coral bleaching on a massive scale and override other stress signals. 

The onset of bleaching mortality was rapid in some corals, notably Millepora and Porites porites, 

whilst the vast majority remained bleached for many months without significant mortality. In 

February 2006, there was a mean of 37.5% of colonies still bleached, although mortality was 

only 3.8%. By June 2006, bleaching persisted in 17.2% of colonies and recent mortality was 

much higher at 18.7%. Inshore reefs were harder hit, with 20.1% colony mortality, compared 

with 17.4% mortality for the offshore reefs. 

Socioeconomic Impacts and Management Responses

The events of 2005 are of great concern for tropical islands like Barbados; particularly as the 

global warming trend is predicted to continue. If SSTs rise by 2-3oC, annual bleaching will 

probably become common in the Caribbean. Therefore, a well-coordinated, regional monitoring 

program is required so that more effective management strategies can be implemented at both 

the regional and local levels. 

Coral reefs are recognized as being particularly important to the Barbados economy; thus the 

Government, through its Coastal Zone Management Unit, has developed a coastal management 

plan with sections devoted specifically to coral reef protection. This includes a long-term 

program of monitoring for reefs at 5 yr intervals on 21 west coast, 16 southwest coast fringing 

and patch reefs and 6 west and southwest coast bank reefs. Previous monitoring indicates that 

much of the reef deterioration on the west coast was the result of increasing nutrients from the 

land. In response, the Government constructed the South and West Coast Sewage Treatment 

Project to reduce pollution. This was part of a coastal zone management plan that outlines 

permitted coastal development and is enforced through the Coastal Zone Management Act, 

which protects all corals from physical damage, and the Marine Pollution Control Act, which 

protects corals from land-based sources of pollution. 

The Government has recognized that healthy reefs are more resilient to coral bleaching and 

other effects of climate change (e.g. potentially greater incidence of coral disease) than degraded 

reefs. As a result, increasing efforts to reduce anthropogenic stress has become a management 

priority. Efforts to manage and conserve coral reefs must include all reef types to cover the 

spectrum of resistance and resilience to bleaching demonstrated by the various coral species 

in different reef habitats. Small, vulnerable states like Barbados should strive to minimize 

anthropogenic effects on corals to conserve coral reef resources locally, and put pressure on 

the international community to reduce global greenhouse gas emissions.
101

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

CORAL MORTALITY IN BARBADOS, MARTINIQUE AND THE 

BRITISH VIRGIN ISLANDS AFTER THE BLEACHING 

The eventual fate of stony corals that have bleached is known to be highly variable among 

sites, and bleaching may persist for many months after seawater temperatures return 

to ‘normal’. The severity of bleaching is likely to be underestimated when surveys are of 

limited duration and spatial coverage, or focused only on coral color. AGRRA scientists 

conducted surveys in Barbados, Martinique and the British Virgin Islands using BLAGGRA; 

a new protocol for rapidly assessing coral condition (available online at www.agrra.org). 

Prolonged exposure to high sea surface temperatures in 2005 had affected Barbados < 

Martinique < British Virgin Islands (BVI), and many surviving corals were still partially pale in 

January 2006; bleaching-related mortality was pronounced in Agaricia agaricites (plus Porites 

porites in Barbados and Martinique). In addition, colonies of Diploria labyrinthiformis and the 

Montastraea annularis complex were being killed by white plague in the southern BVI. Recent 

partial-colony mortality estimates of all the ≥ 10 cm corals in belt transects were 5% in 

Barbados (n = 10 sites), and 11-13% in the southern BVI and Martinique, respectively (n = 

7 sites each). Average ‘recent loss’ of live coral cover in line transects showed similar losses 

from about 7% in Barbados to about 15% in Martinique and the southern BVI. Despite 

regaining much of their pigmentation, stony corals continued to die during spring 2006, 

apparently from the delayed effects of bleaching in Barbados, and, in part, from diseases 

that were conspicuous for several months in southern Martinique. When most sites were 

resurveyed in May to early June, recent partial-colony estimates had tripled at repeat sites 

in Barbados and nearly doubled in Martinique. These dramatic increases are most probably 

disease-related to the 2005 bleaching 6 months earlier. They demonstrate how essential 

repeated post-mortem surveys are for at least 6 months after initial bleaching to evaluate 

the full impact of an event. 

We thank the National Oceanic and Atmospheric Agency’s CHAMP and our home institutions 

for financial and in-kind support; from: Judith Lang, PO Box 539, Ophelia, VA 22530. jlang@

riposi.net; Robert Ginsburg, Marine Geology and Geophysics, Rosenstiel School of Marine 

and Atmospheric Science, University of Miami, Miami, FL 33149, rginsburg@rsmas.miami.

edu; Kenneth Marks, Ocean Research and Education Foundation, 1300 Galiano, Coral Gables, 

FL 33134, USA; Hazel Oxenford, Centre for Resource Management and Environmental 

Studies, University of the West Indies, Cave Hill Campus, St Michael, Barbados; Jean-Philippe 

Marechal, L’Observatoire du Milieu Marin de la Martiniquais, 3, Avenue Condorcet, 97200 

Fort de France, Martinique; Shannon Gore, Conservation and Fisheries Department, P.O. 

Box 3323, Road Town, Tortola, British Virgin Islands). 
102

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Trinidad and Tobago

Introduction

The reefs of the island of Tobago are far more extensive than those on the larger island of 

Trinidad. Tobago’s reefs are a mixture of biogenic reefs (built by corals and coralline algae) and 

geological reefs (base of rock, colonized by hard corals). Most of the reefs are ‘shallow’ in their 

structure, ending abruptly in a sand seabed at depths between 15 m and 25 m. 

Status of Coral Reefs Prior to 2005

The most commonly occurring corals are the Montastraea annularis complex, which occupied 

37% of the substrate, with fire corals (Millepora spp.) contributing 12%, and the ‘brain’ corals, 

Colpophyllia natans and Diploria strigosa, contributing 11% and 9% respectively. Agaricia spp. 

and the branching corals (Porites porites, P. furcata and P. divaricata) are far less abundant than 

on many other Caribbean reefs. This is similar for macro-algae, which covered less than 3% of 

the substratum, with uncolonized rock accounting for 41%. Coral disease, tissue necrosis or 

turf-algal/cyanobacterial overgrowth of bleached or unbleached corals has not been recorded 

during previous surveys, indicating that the reefs were predominantly healthy prior to 2005. 

Effects of the 2005 Bleaching Event

Following warnings of potential bleaching in 2005, the Buccoo Reef Trust and Coral Cay 

Conservation assessed 22 discreet reef sites on the Caribbean coast in October/November. 

Surveys at two deep (~12 m) and two shallow (~7 m) sites showed that coral cover was highly 

variable around the island. The mean cover was 21.4% (SD ± 12.9%), with the maximum cover 

recorded being 60% at Pirate’s Bay on the north-west coast. Coral cover was greater at deeper 

sites (~24%) than shallower ones (~19%). 

The first bleaching was noticed in Palythoa and fire corals (Millepora) in September 2005. 

By October/November, bleaching affected 66% of hard corals (71% on deeper sites and 63% 

on shallow sites). The extent of bleaching was largely consistent throughout, with most sites 

showing extensive bleaching (> 85%). However, there was less than 20% bleaching along 9 

transects, 5 of which were located near Speyside in the northeast of Tobago. This may indicate 

either localized tolerance to bleaching or better water quality with either less polluted water or 

cooler water entering the area. 

The incidence of bleaching was highly variable within and between species. Agaricia agaricites 

and Siderastrea radians were most affected, with 93% of colonies being bleached. Madracis 

mirabilis and Acropora palmata were the least affected species (3% and 0% respectively). 

The once prominent A. palmata is becoming particularly rare throughout the Caribbean, 

however there was no bleaching seen on the few colonies on or adjacent to the transects. The 

average incidence of bleaching among species of the Montastraea annularis complex was 73%, 

although there was great variability between these species. For example, at one site at Buccoo 

Reef, one stand of M. annularis exhibited 97% bleaching while bleaching affected only 6% of 

the surface area of an adjacent stand. This probably demonstrates the presence of bleaching 

resistant clades (genetic varieties) of the coral and/or the algal symbionts.
103

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching Event

By March 2006, only 7% of 180 colonies that had been tagged in November had died. The 

majority of these corals regained their pigmentation, although partial mortality was evident 

in 32.5% of the colonies, including some with clear symptoms of coral disease. Mortality was 

greatest in brain corals (Colpophyllia natans, Diploria strigosa and Diploria labyrinthiformis), 

with 73% of colonies dying. Most of the reefs had still not recovered from the bleaching event 

of 2005, with many colonies showing signs of diseases and an apparent rise in colony mortality 

among the massive corals.

Socioeconomic Impacts and Management Responses

After the 2005 event, the Buccoo Reef Trust introduced a monitoring program under the 

regional GEF-IWCAM project and Coral Cay Conservation started coral reef mapping around 

Tobago. These studies, conducted in partnership with the Tobago House of Assembly, will 

provide detailed information about the long-term damage to the island’s coral reefs from the 

2005 bleaching event.

Author Contacts

Claude Bouchon, Pedro Portillo, Yolande Bouchon-Navaro, Max Louis, Université des antilles 

et de la Guyane, Laboratoire de Biologie Marine, Pointe-à-Pitre, Guadeloupe. claude.bouchon@

univ-ag.fr; Paul Hoetjes, Department of Environment & Nature, Ministry of Public Health & 

Social Development, Curaçao, Netherlands Antilles. paul@mina.vomil.an; Hazel Oxenford, 

Centre for Resource Management and Environmental Studies (CERMES), University of the West 

Indies, Cave Hill, Barbados; Angelique Brathwaite, Ramon Roach, Coastal Zone Management 

Unit (CZMU), Ministry of Housing, Lands and the Environment, Government of Barbados, 

Barbados. abrathwaite@coastal.gov.bb. Shay O’Farrell, Coral Cay Conservation, London, United 

Kingdom. science@coralcay.org, Owen Day, Buccoo Reef Trust, Carnbee, Tobago, Trinidad and 

Tobago. o.day@buccooreef.org

References

Environmental Assessment Programme, Office of Research, University of the West Indies (2007). 

The Barbados Coral Reef Monitoring Programme; Changes in coral reef communities 

on the West and South Coasts 1987-2002. Coastal Zone Management Unit, Government 

of Barbados.

Government of Barbados (GOB) (2004). The national biodiversity strategy and action plan 

for Barbados. Ministry of Physical Development and Environment, Government of 

Barbados

O’Farrell S, Day O (2006). Report on the 2005 mass coral bleaching event in Tobago, Part 1: 

Results from Phase 1 Survey. Coral Cay Conservation and the Buccoo Reef Trust. 41 pp. 

(http://www.coralcay.org/science/publications/trinidad.pdf).

Oxenford HA, Roach R, Brathwaite A, Nurse L, Goodridge R, Hinds F, Baldwin K, Finney C (2007). 

Quantitative observations of a major coral bleaching event in Barbados, southeastern 

Caribbean. Climatic Change, published online 6 September, 2007.
105

Summary

zx Massive coral bleaching occurred in Southern Tropical America during unusually 

high sea surface temperatures in 2005. The timing of bleaching varied throughout the 

region. 

zx Surveys at 156 sites in Brazil, Colombia and Venezuela show that 2005 was the region’s 

most severe bleaching year, with most bleaching in shallow zones, but the severity 

varied considerably. 

zx In Brazil, bleaching started at Itacolomis Reefs in April 2005, after the southern 

summer. 

zx In Colombia, reefs at Santa Marta started bleaching 6 months later in October, after the 

northern summer. 

zx In Venezuela, the peak bleaching intensity was in November-December 2005, two months 

later than in the west and north Caribbean. It affected up to 25% of coral colonies but 

varied greatly among surveyed sites, from 0 to 100%. 

zx Bleaching was observed in several coral species but only a few, such as Acropora 

cervicornis, A. palmata, and Diploria labyrinthiformis, suffered mortality. 

zx Coral reefs less affected by bleaching seem to be related to upwelling zones in the 

Caribbean.

9. The Effects of Coral Bleaching in Southern

Tropical America: Brazil, Colombia, and Venezuela

Alberto Rodríguez-Ramírez, Carolina Bastidas, Sebastián Rodríguez, 

Zelinda Leão, Ruy Kikuchi, Marília Oliveira, Diego Gil, Jaime

Garzón-Ferreira, María Catalina Reyes-Nivia, Raúl Navas-Camacho, 

Nadiezhda Santodomingo, Guillermo Díaz-Pulido, Dagoberto

Venera-Ponton, Lenin Florez-Leiva, Alejandro Rangel-Campo, Carlos

Orozco, Juan Carlos Márquez, Sven Zea, Mateo López-Victoria, Juan

Armando Sánchez and Maria Clara Hurtado.
106

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Map of the Southern Tropical America region.

Introduction

The Southern Tropical America (STA) Node of the GCRMN includes Costa Rica, Panama, 

Colombia, Venezuela, and Brazil, with reefs in Pacific, Caribbean and Atlantic waters. The 

Node is coordinated by the ‘Instituto de Investigaciones Marinas y Costeras’ (INVEMAR) in 

Colombia, with support from UNEP-CAR/RCU in Jamaica; the Node has been developing coral 

reef monitoring in this region since 1999. 

Most coral reefs in the region have undergone major changes in the last 30 years, particularly 

during the 1980s, with considerable loss of live coral cover on many reefs and increasing 

dominance of algae. Nevertheless, high coral cover can still be found on many reefs on both 

the Caribbean coast (means between 20-40%) and the Pacific coast (means above 40%). 

Some changes were caused by ‘natural’ agents (ENSO events, bleaching, disease outbreaks, 

phytoplankton blooms), but others are clearly related directly to human activities (deforestation, 

increased sedimentation, coastal development, sewage pollution, over-fishing). The 1997-98 

El Niño events had little effect on reefs in the region. Monitoring data from the 5 countries 

indicate that reefs of the STA region did not change significantly between 2000 and 2004. Mass 

coral bleaching was recorded in the region during 2005 although some reefs were not affected 

(e.g. Costa Rica). Thus, this report focuses on the effects of coral bleaching events in Brazil, 

Colombia, and Venezuela.

##

80° W 

80° W 

70° W 

70° W 

60° W 

60° W 

50° W 

50° W 

40° W 

40° W 

17° S 17° S 

7°S 7°S 

3°N 3°N 

13° N 13° N 

0 5 25 0 00 1,00 0 

Kilometers

BRAZIL

BOLIVI A

PARAGUAY

CHILE

PERU 

ECUADOR 

COLOMBIA

VENEZUEL A

GUYANA

SURINAME

FRENCHGUYAN A 

PANAMA

P a cifi c 

Ocea n 

Atla n t i c

Ocea n 

LEGEND

Coral Reefs 

Bonaire 

Tobago

Atoll de

Rocas 

Curacao 

San Blas 

Gulf of

Chiriqui 

Gorgona 

Santa Marta 

Abrolhos 

Arch

Maceio

Los 

Roques 

Isla Margarita

Itacolomis

Natal
107

The Effects of Coral Bleaching in Southern Tropical America: Brazil, Colombia, and Venezuela

Brazil

Introduction

The coral reefs of Brazil have low coral diversity (18 species with 6 endemic) and are 

discontinuously distributed in 5 major areas along the 2500 km western Atlantic coastline: 

Touros-Natal has extensive coastal knoll and patch reefs; Pirangi-Maceió has linear coastal 

reefs and higher species diversity; Todos os Santos Bay-Camamu; Porto Seguro-Cabrália; and 

the Abrolhos Region to the east and south. The National Marine Park of Abrolhos covers 900 

km2 and contains the richest coral reefs in Brazil, including the Timbebas Reefs (isolated 

coastal bank reefs), fringing reefs on offshore volcanic islands of the Abrolhos Archipelago, and 

the ‘chapeirões’, which are giant mushroom-shaped coral pinnacles 70 km offshore.

Status of Coral Reefs Prior to 2005 

The first record of coral bleaching was in the Abrolhos area of Eastern Brazil in 1994. In 1998, 

bleaching was observed in Bahia, north of Salvador City and in the Abrolhos, when sea surface 

temperatures (SSTs) increased in mid January and peaked between mid March and April, before 

declining in late May. The SSTs ranged between 29.5°C and 30.5°C; or 1-2°C higher than the 

long-term average summer maximum of 28.5°C. In 2003, two ‘hot spots’ occurred in Eastern 

Brazil (Tinharé and Abrolhos) when SSTs rose in mid February and were 1°C above the long 

term average in mid March; the hot spots dissipated in late April with up to 20% of coral 

colonies bleached in Tinharé, and 17% in Abrolhos (SST anomalies are based on ‘HotSpot’ 

charts in www.osdpd.noaa.gov/PSB/EPS/SST/climahot.html).

Effects of the 2005 Bleaching Event

Two reefs in Southern Bahia, Itacolomis and Abrolhos, were affected by increased SSTs in 

mid-March 2005 with a maximum rise of 0.75°C above the long-term average. The ‘HotSpots’ 

dissipated by the end of April, however, coral bleaching was observed on the Itacolomis Reefs 

during April, with up to 17% of colonies affected. About 28% of coral colonies were bleached 

on the Abrolhos reefs in early May. The coincidence of mass coral bleaching events in Eastern 

Brazil and high SSTs during the last 8 years strongly indicates that these temperature increases 

are the primary cause of bleaching in the region. Bleaching was mild in Bahia in 2006 with 

only 6.2±7.1% of colonies bleached on the Abrolhos fringing reefs, compared with 28.3±4.9% 

in 2005. Live coral cover increased from 11.4 ±5.0% (2005) to 13.5 ±3.5% (2006), with no rise 

in recent mortality. The amount of dead coral declined from 20.5% (2005) to 17.5% (2006).

Percentage of bleached coral colonies observed on Brazilian reefs in 2005 and 2006 from 

assessments performed using the AGRRA protocol.

Reefs Time of 

observation Number reef sites No. colonies observed 

Percentage 

bleached colonies

Itacolomis April 2005 3 280 4.7 – 17.0

Abrolhos May 2005 3 399 23.5 – 33.3

Abrolhos March 2006 6 553 2.0 – 17.0
108

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Colombia

Introduction

The Caribbean coast of Colombia has reefs on a 40 km wide continental shelf, which are strongly 

influenced by freshwater and sediment runoff, particularly from the Magdalena River, which is 

the largest river flowing into the Caribbean. The coral reefs cover more than 2800 km2 and are 

scattered among 26 areas in 3 major groups. The mainland coast has fringing reefs on rocky 

shores, such as the Santa Marta and Urabá areas. There are many well-developed reefs around 

offshore islands, including the Islas de San Bernardo and Islas del Rosario, on the continental 

shelf, and oceanic reef complexes of the San Andrés Archipelago in the Western Caribbean. 

These are the best developed coral formations, including atolls, banks, barrier reefs, fringing 

reefs and patch reefs, and comprise more than 75% of Colombia’s coral reefs. Pacific reefs are 

poorly developed, with only Gorgona Island having large coral formations.

Status of Coral Reefs Prior to 2005

The Caribbean reefs were degraded by pollution, sedimentation, over-fishing, dynamite fishing, 

and coral mining during the 1980s, with mass mortality of gorgonians, coral bleaching, 

and declines in sea urchin (Diadema antillarum) populations. Bleaching was reported on 

Colombian Caribbean reefs in 1987, 1990, 1995 and 1998. The 1987 Caribbean-wide event 

affected the Santa Marta region, Rosario Islands and Bahía Portete (Guajira area), but was poorly 

documented. During 1990 and 1995, minor bleaching events were observed at Islas del Rosario 

and Chengue respectively. The 1997-98 El Niño event had little effect on Colombian Caribbean 

reefs. Coral bleaching affected less than 5% of coral colonies at sites monitored between 1998 

and 2001, except in Chengue where it was 10%; but coral mortality was negligible. However, 

coral communities in Chengue were damaged in late 1999 by Hurricane Lenny, reducing coral 

cover from 35% to 31%. Colombian Caribbean reefs have changed little since the mid-1990s; 

coral cover has ranged between 31% and 35% in Chengue Bay, 28% and 32% at Rosario Islands, 

and 22% and 28% at San Andrés Island. Coral diseases affect less than 5% of coral colonies at 

all sites, except San Andrés, where 9.1% and 6.3% of colonies were affected in 1999 and 2001 

respectively. Dark spot and white plague are the most common coral diseases on Colombia’s 

Caribbean reefs.

IDENTIFICATION OF BLEACHING-SUSCEPTIBLE 

ZOOXANTHELLAE IN COLOMBIAN CORALS.

Bleached colonies of Colpophyllia natans, Montastraea faveolata, M. annularis, Agaricia 

tenuifolia, and Porites astreoides from the coral reefs near Cartagena, Colombia were 

examined with molecular techniques to identify bleaching resistance or susceptibility 

in the zooxanthellae; 41.7% of bleached corals contained zooxanthellae clades A, C and 

D. There were however, many different sub-types of zooxanthellae in clades A and C, 

with most of these types susceptible to bleaching in 2005. When colonies of Montastraea 

faveolata and Diploria labyrinthiformis were re-sampled after the bleaching event, the 

zooxanthellae were predominantly of thermally tolerant clade D, corresponding with 

predictions of thermal acclimation (from Maria Clara Hurtado, mar-hurt@uniandes.edu.

co and Juan Armando Sánchez, juansanc@uniandes.edu.co) 
109

The Effects of Coral Bleaching in Southern Tropical America: Brazil, Colombia, and Venezuela

Effects of the 2005 Bleaching Event

Surface waters in Colombia were unusually warm in 2005. The first increases in sea temperature 

along the Caribbean coast were observed in mid-May and peaked at 1.5-2.5°C higher than the 

monthly mean in the 3rd and 4th weeks of June. This coincided with the first observations of 

mass coral bleaching at Islas del Rosario. 

The 2005 bleaching event was the most severe for the Colombian Caribbean in the last 25 

years. The severity of bleaching varied between the 137 study sites: Rosario and San Bernardo 

suffered severe bleaching; San Andrés and Providencia were moderately affected; and Santa 

Marta experienced minimal bleaching. However, corals in the Santa Marta area bleached in 

October, 4 months after corals on reefs such as Islas del Rosario, which is 200 km to the 

southwest. This might have been a result of seasonal upwelling peaks that occurred early in 

the year and in July-August. 

There was great variation between sites, with the cover of bleached coral and the proportion 

of bleached colonies ranging between 0.5-80% and 0.6-100% respectively. However, coral 

mortality was generally low with less than 5% variation between areas and stations. Most 

coral species showed some bleaching, especially those in water shallower than 10 m. The 

greatest bleaching mortality occurred at Islas del Rosario and Islas San Bernardo, mainly 

among colonies of Acropora palmata, A. cervicornis, Diploria labyrinthiformis and Millepora 

alcicornis. Extensive patches (> 100 m2

) of recently dead A. palmata and A. cervicornis were 

observed. Subsequent mortality was also observed in tagged colonies that were re-examined 

two months after the peak of bleaching; some of these colonies were greater than 50 cm in 

diameter. However, most reefs that suffered bleaching had recovered within 6 months of the 

onset of the event.

IS COMPETITION FOR SPACE BETWEEN THE ENCRUSTING 

EXCAVATING SPONGE CLIONA TENUIS AND CORALS 

INFLUENCED BY HIGHER TEMPERATURES?

The rate of lateral overgrowth by excavating sponges was measured to see whether 

heat stress in corals may make them more susceptible to encroachment. There was 

no change in rate of lateral spread of the sponge Cliona tenuis growing over colonies of 

the corals Diploria strigosa and Siderastrea siderea at 5-6 m depths between June 2001 

and July 2002, when there was no unusual warming, and in August 2004 and September 

2005, which coincided with significant warming. Sponge spreading on S. siderea remained 

constant, but was more variable on D. strigosa, irrespective of whether there was partial 

or total bleaching of the corals. These experiments indicate that there may be differential 

susceptibility to excessive warming within and between coral species and perhaps 

between individual sponges (from Juan Carlos Márquez, juancmarquezh@gmail.com; 

Sven Zea, szea@invemar.org.co; and Mateo López-Victoria, Mateo.Lopez-Victoria@bio.

uni-giessen). 
110

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Seagrass and mangrove communities monitored at Chengue Bay during 2005 did not show 

significant changes from the 2005 bleaching event. There was no bleaching in the Colombian 

Pacific at Malpelo Island in June and Gorgona Island in October.

The impacts of coral bleaching on the reefs of Colombia in 2005 are summarized in this table 

showing the effect on coral cover and the number of bleached colonies. The effects on the reefs varied 

considerably within sites with low resultant mortality.

Colombian 

Caribbean Reefs

Sites 

Examined

Coral 

Cover Bleached

Coral Colonies 

Bleached

Coral 

Mortality

Islas del 

Rosario-Cartagena 48 0.5-80% 29-100% 0-2%

Islas San Bernardo 18 0.5-70% 50-100% 0-5%

San Andres 30 1-15% 7-60% ?

Providencia 29 1-10% 0.6-54% ?

Santa Marta-Parque 

Tayrona 12 1-5% 0-15% 0-1%

Impacts of Hurricanes in 2005

Hurricane Beta was a moderate category 1 hurricane that passed very close to Providencia 

and Santa Catalina Islands on 29 October 2005. When 20 sites were examined 15 days later, 

there was negligible damage to coral reefs, seagrass beds, beaches and mangroves; however, 

terrestrial vegetation and island infrastructure were severely damaged.

Venezuela

Introduction

The coast of Venezuela is 2875 km long and with most of this (67%) in the Caribbean where 

the reefs are found. There are no reefs along the Atlantic coast because of freshwater and 

sediment runoff, and upwellings. Nearshore coral reefs occur only in Moroccoy National Park 

and adjacent areas (San Esteban, Turiamo and Ocumare de la Costa), with more than 30 coral 

species and reef growth to 20 m depth; and Mochima National Park and adjacent reefs (Coche 

and Cubagua islands), with more than 20 coral species to depths of 14 m. The best developed 

reefs are around the oceanic islands, especially at Archipelago de Aves, Archipelago Los Roques, 

La Orchila and La Blanquilla, which have 57 coral species growing to great depths e.g. 57 m.

Status of Coral Reefs Prior to 2005

The oceanic reefs of Venezuela were once among the few virtually pristine reefs in the Caribbean, 

but surveys since 2003 showed sites varied between 18% and 51% mean coral cover. The 

exception was the coastal coral reefs at Parque Nacional Morrocoy (PNM), which were severely 

degraded in 1996, probably by chemical pollution or a severe phytoplankton bloom, followed 

by sudden oxygen depletion caused by a climate and oceanic anomaly. Coral cover dropped 

from 43% to less than 5% at the former CARICOMP reef site of Bajo Caiman. Subsequent 

CARICOMP surveys at Bajo Cayo Sombrero, one of the few reefs in the park with live corals, 

indicated that the coral community was in a relatively stable condition, with more than 35% 
111

The Effects of Coral Bleaching in Southern Tropical America: Brazil, Colombia, and Venezuela

coral cover. Several coral diseases including yellow band, black band, white diseases, dark spots 

and ciliate infections had affected the corals.

The table shows the percentage of bleached colonies of zoanthids, octocorals and hard 

corals in Venezuela, between August 2005 and February 2006. The intensity is recorded as 

the surface area of the colony affected at oceanic reefs: Isla La Blanquilla (LB) and Parque 

Nacional Archipiélago Los Roques (Pnalr); and coastal reefs: Parque Nacional Morrocoy 

(PNM-RFSC) on the western coast and Parque Nacional Mochima (PNM) on the eastern 

coast that is influenced by upwelling. BCS is the CARICOMP site of Venezuela at PNMRFSC, which was examined during each sampling period (n = number of colonies surveyed; 

N = number of sites surveyed at each location). 

Time of 

observation

Location 

(N)

Coastal/ 

Oceanic

<10 10-

25

25-

50

50-75 75-

100

Bleached 

Colonies 

%

n

Aug-Sep 2005

LB (1) Oceanic 0.0 1.7 0.4 0.9 0.7 3.7 461

Pnalr (2) Oceanic 0.4 0.0 0.0 0.0 0.0 0.4 275

BCS (1) Coastal 0.0 0.0 0.0 0.0 0.0 0.0 160

PNMRFSC (3)Coastal 0.0 0.0 0.0 0.0 0.0 0.0 352

Nov-Dec 2005

BCS (2) Coastal 5.6 4.1 4.6 0.5 11.7 26.5 196

PNMRFSC (4)Coastal 2.2 2.1 1.7 0.8 3.4 10.2 715

Jan-Feb 2006

Pnalr (1) Oceanic 0.0 0.0 0.0 0.0 0.0 0.0 643

PNM (1) Coastal 0.0 0.0 0.0 0.0 0.0 0.0 181

BCS (1) Coastal 4.1 2.1 6.7 2.1 2.1 17.1 193

Effects of the 2005 Bleaching Event

There was no bleaching among 352 coral colonies at 3 coastal reef sites in August-September. 

However, there was minor bleaching at 3 oceanic sites, with 1% of 275 colonies affected at 

Parque Nacional Archipiélago de Los Roques and 4% of 461 colonies at Isla La Blanquilla, but 

bleaching usually affected less than 10% of the colony surface.

By November-December 2005, up to 25% of 715 coral colonies had bleached at 5 coastal sites in 

Parque Nacional Morrocoy, with hard corals, soft corals and zoanthids showing bleaching over 

more than 50% of their surface. Bleaching varied between species: there was 50% bleaching in 

Montastraea franksi; 48% in M. faveolata; 14% in Colpopohyllia natans; 50% in Meandrina 

meandrites; 16% in Agaricia agaricites; 7% in the hydrocoral Millepora; 65% in the encrusting 

octocoral Erythropodium caribaeorum; and 85% in the zoanthid Palythoa mammillosa.

Bleaching was still evident in January-February 2006 at one coastal reef site in Parque Nacional 

Morrocoy and 4 oceanic sites at Parque Nacional Archipiélago de Los Roques. Bleaching was 

not observed at Parque Nacional Archipiélago de Los Roques in the Acropora palmata zone (n = 

Surface area of the colony bleached %
112

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

643); however, about 10% of colonies of Montastraea faveolata were bleached at other depths. 

The bleached colonies showed recovery at the coastal site of Cayo Sombrero (BCS), going from 

26% bleached (n = 196) in November-December to 17% (n = 193). Severely bleached corals 

(those with more than 75% of the surface bleached) dropped from 11% in August-September 

to less than 2% in January-February 2006. There was no bleaching seen at the other 3 coastal 

reef sites in Parque Nacional Mochima, probably because these sites are in the characteristic 

upwelling area of the eastern coast. 

The 2005 bleaching event also affected other reefs in Venezuela; however, the peak bleaching 

intensity was 2 months later than other Caribbean sites to the west and north. Bleaching 

appeared to start on the oceanic reefs, although coastal reefs were eventually more severely 

affected. The Parque Nacional Mochima was least affected, probably because of the influence of 

upwelling and lower sea surface temperatures (23oC during surveys) compared with the other 

reefs (>27oC). Peak bleaching occurred in November-December 2005. There was no increase 

in the prevalence of coral diseases or loss of coral cover after the 2005 bleaching at any of the 

5 monitoring sites.

Conclusions and Recommendations

During the Southern and Northern Summers of 2005, the Southern Tropical America region 

experienced the most severe coral bleaching event for decades. Bleaching was widespread, 

occurring throughout the region from the oceanic reefs of Colombia in the Southwestern 

Caribbean to Brazilian reefs in the Western Atlantic. However, the severity of bleaching varied 

greatly and bleaching mortality was generally low. Nevertheless, extensive areas of Acropora 

palmata and A. cervicornis were killed in a few localities, highlighting that these are particularly 

vulnerable species. Some reefs had minor bleaching (e.g. Santa Marta, Colombia and Parque 

Nacional Mochima, Venezuela), which could be attributable to the seasonal upwelling in these 

areas. It is important to understand the differential response to widespread bleaching events 

so that more resistant coral reefs can be conserved to serve as future sources of larvae for 

recovery.

Acknowledgements

The Southern Tropical America Node has been supported through the ‘Instituto de Investigaciones 

Marinas y Costeras’ (INVEMAR) and the Regional Coordinating Unit for the Caribbean of UNEP 

(UNEP-RCU/CAR). Additional support has come from: INTECMAR-Universidad Simon Bolívar, 

Universidade Federal da Bahia, Laboratório de Estudos Costeiros, STRI-Panamá; CIMARUniversity of Costa Rica; and agencies from each country (CORALINA, UAESPNN, CEINER, 

Marine Park of Abrolhos and the International Conservation of Brazil), and CARICOMP and 

AGGRA. The Colombian Science Fund-COLCIENCIAS, Fondo para la Promoción de la Ciencia 

y la Tecnología del Banco de la República, Universidad Nacional de Colombia, Universidad de los 

Andes-BIOMMAR, Universidad del Magdalena-FONCIENCIAS, Brazilian National Foundation 

for the Development of Science, and the Foundation for Development of Science of the State of 

Bahia (FAPESB) supported activities. Many people provided information or helped in the field: 

J.C. Vega, J. Olaya, S. Posada, A. Chaves, V. Testa, L. Dutra, S. Spano, C. Sampaio, B. Feitosa, M. 

Telles, R. Silva, I. Cruz, A.B Neto, S. Marques Pauls, A. Soto, and D. Ancieta.
113

The Effects of Coral Bleaching in Southern Tropical America: Brazil, Colombia, and Venezuela

Author Contacts

Brazil: Zelinda Leão (zelinda@ufba.br), Ruy Kikuchi (kikuchi@ufba.br), Marília Oliveira 

(mariliad@ufba.br), Universidade Federal da Bahia, Laboratório de Estudos Costeiros, CPGG/

IGEO. Colombia: Alberto Rodríguez-Ramírez (betorod@invemar.org.co), Diego Gil (diego.

gil@invemar.org.co), Jaime Garzón-Ferreira (anisotremus@gmail.com), María Catalina 

Reyes-Nivia (macatareyes@gmail.com), Raúl Navas-Camacho (rnavas@invemar.org.co), 

Nadiezhda Santodomingo (nadiaks@invemar.org.co), Instituto de Investigaciones Marinas 

y Costeras-INVEMAR. Guillermo Díaz-Pulido (g.diazpulido@uq.edu.au), Centre for Marine 

Studies, University of Queensland and Universidad del Magdalena. Dagoberto Venera-Ponton 

(dagovenera@gmail.com), Lenin Florez-Leiva (lenin.florez@gmail.com), Alejandro RangelCampo (ajrangelc@gmail.com), Universidad del Magdalena. Carlos Orozco (calotoro@yahoo.

com), Corporación para el Desarrollo Sostenible del Archipiélago de San Andrés, Providencia 

y Santa Catalina-CORALINA. Juan Carlos Márquez (juancmarquezh@gmail.com), Sven Zea 

(szea@invemar.org.co), Universidad Nacional de Colombia, Departamento de Biología y Centro 

de Estudios en Ciencias del Mar-CECIMAR. Mateo López-Victoria (Mateo.Lopez-Victoria@bio. 

uni-giessen.de), Institut für Allgemeine und Spezielle Zoologie, Justus-Liebig Universität. 

Juan Armando Sánchez (juansanc@uniandes.edu.co), Maria Clara Hurtado (mar-hurt@

uniandes.edu.co), Universidad de los Andes, Departamento de Ciencias Biológicas, Laboratorio 

de Biología Molecular Marina - BIOMMAR. Venezuela: Carolina Bastidas (cbastidas@usb.ve), 

Sebastián Rodríguez (sebastianr@usb.ve), Universidad Simon Bolivar, Depto. de Biología de 

Organismos, Instituto de Tecnología y Ciencias Marinas-INTECMAR.

References

Castellano P, Varela R, Muller-Karger F (2000). Descripción de las áreas de surgencia al sur del 

Mar Caribe examinadas con el censor infrarrojo AVHRR. Memorias de la Fundación La 

Salle de Ciencias Naturales 154:155-75.

Cróquer A, Debrot D, Klein E, Kurten M, Rodríguez S, Bastidas C, (in press). What can two 

years of monitoring tell us about Venezuelan coral reefs? The South Tropical America 

Coral Reef Monitoring Network (STA-GCRMN). Rev. Biol. Trop. 

Cróquer A, Bone D (2003). Las enfermedades en corales escleractínidos: ¿Un nuevo problema 

en el arrecife de Cayo Sombrero, Parque Nacional Morrocoy, Venezuela? Revista de 

Biología Tropical 51(6):167-172.

Garzón-Ferreira J, Díaz JM (2003). The Caribbean coral reefs of Colombia. Pp 275-301. In: 

J. Cortés (Ed.) Latin America Coral Reefs, Elsevier Science.

Gil DL, Garzón-Ferreira J, Rodríguez-Ramírez A, Reyes-Nivia MC, Navas-Camacho R, VeneraPontón DE, Díaz-Pulido G, Sánchez JA, Hurtado MC, Orozco C (2006). Blanqueamiento 

coralino en Colombia durante el año 2005. Pp 83-87. In: Informe del Estado de los 

Ambientes Marinos y Costeros en Colombia: Año 2005. INVEMAR. Serie de Publicaciones 

Periódicas No. 8. Santa Marta.

Kikuchi RKP, Leão ZMAN, Testa V, Dutra LXC, Spanó S (2003). Rapid assessment of the Abrolhos 

Reefs, Eastern Brazil (Part 1: stony corals and algae). Atoll Research Bull. 496:172-187

Laboy-Nieves EN, Klein E, Conde JE, Losada F, Cruz JJ, Bone D (2001). Mass mortality of tropical 

marine communities in Morrocoy, Venezuela. Bulletin of Marine Science 68:163- 179

Leão ZMAN, Kikuchi RKP, Testa V (2003). Corals and Coral Reefs of Brazil. Pp 9-52. In: J. Cortés 

(Ed.) Latin America Coral Reefs, Elsevier Science.

Rodríguez-Ramírez A, Reyes-Nivia MC (2006). Evaluación rápida del impacto del huracán Beta 

sobre los ecosistemas marinos y costeros de la Isla de Providencia. Pp 87-92. In: Informe 
114

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

del Estado de los Ambientes Marinos y Costeros en Colombia: Año 2005. INVEMAR. 

Serie de Publicaciones Periódicas No. 8. Santa Marta.

Rodríguez-Ramírez A, Reyes-Nivia MC, Navas-Camacho R, Vega-Sequeda J, Olaya J, Duque 

G, Garzón-Ferreira J, Zapata, Orozco C (2006). Estado de los arrecifes coralinos en 

Colombia. Pp 71-82. In: Informe del Estado de los Ambientes Marinos y Costeros en 

Colombia: Año 2005. INVEMAR. Serie de Publicaciones Periódicas No. 8. Santa Marta.
115

Introduction

This volume documents the severe consequences that climate change is predicted to have 

for coral reefs worldwide. While there are expected to be many impacts on coral reefs from 

climate change, the most immediate and dramatic are associated with rising sea temperatures 

and resultant mass coral bleaching events. These events have already been responsible for 

long-term damage to more than 16% of the world’s reefs and with causing serious, although 

largely unmeasured, hardship for the people who depend on the reefs. As evidence of these 

socio-ecological impacts grows, so does attention on the associated management question: 

are there any actions that coral reef managers can implement to help reefs in the face of 

climate change?

Traditional management approaches that focus on minimizing or eliminating sources of stress 

can not address the threat of mass coral bleaching. Coral reef managers are unable to directly 

mitigate the main cause of mass bleaching; above average water temperatures. This makes 

mass bleaching a uniquely challenging environmental management problem.

In working with colleagues from around the globe to compile the publication, A Reef 

Manager’s Guide to Coral Bleaching (see ref. 5), we determined that there is much that 

managers can do to help reefs cope with climate change. While reef managers cannot directly 

limit climate change, there is a rapidly growing body of scientific knowledge that provides the 

basis for a meaningful response to climate-related threats, such as coral bleaching. Central 

to this response are strategies for supporting the resilience of coral reef ecosystems and the 

people that depend on them. This chapter presents the key elements of a resilience-based 

approach to managing coral reefs in the face of climate change, focusing on:

zx Defining socio-ecological resilience;

zx Describing the process through which unusually high sea temperatures can lead to 

loss of the ecological services that reefs provide to people;

zx Identifying management opportunities that exist at each stage of this process to 

minimize negative impacts; and,

zx Recommending 5 strategies for supporting socio-ecological resilience to mass coral

bleaching. 

10. Managing for Mass Coral Bleaching:

Strategies for Supporting Socio-ecological

Resilience

Heidi Schuttenberg and Paul Marshall
116

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

What Does it Mean to Manage for Socio-Ecological Resilience?

Resilience comes from the Latin, ‘resilere’, which means ‘to spring back’. Managing for 

socio-ecological resilience recognizes that a process of uncertain change is underway, and it 

aims to support the ability of the environment and dependent human communities to absorb 

shocks, regenerate, and reorganize to maintain vital functions and processes. Importantly, 

socio-ecological resilience explicitly considers that social and ecological systems are intrinsically 

linked and that the resilience of each component of the system is related to its linkages to other 

components. 

For ecosystems, resilience can be characterized as the capacity to maintain the provision of 

ecosystem goods and services. For coral reefs, this may mean the capacity of the ecosystem to 

maintain a dominance of hard corals, adequate structural (habitat) complexity, and positive 

rates of reef growth. A reef system with low resilience would readily lose coral cover, potentially 

become dominated by algae, provide reduced habitat, and have a net erosion of reef material. 

The factors that support coral reef ecosystems’ resilience to mass bleaching events can be 

broadly grouped into 4 categories: ecosystem condition; biological diversity; connectivity 

between areas; and local environmental conditions. 

For social systems associated with coral reefs, resilience is determined by the ability to cope with 

changes in the availability or quality of the goods and services provided by coral reefs. Resilient 

social systems have the capacity to anticipate, prepare, and adapt to change to minimize 

the effects on social and economic well-being. The factors that determine the resilience of 

dependent human communities when coral reefs degrade include people’s skills, resources, 

attitudes, resource dependency, and attributes of their broader socio-ecological context (4).

Managing for resilience differs from traditional coral reef management in 2 ways. Rather than 

having a goal to maintain circumstances as they are today, managing for resilience emphasizes 

protecting the factors that allow the socio-ecological system to respond successfully to 

disturbance events. Managing for resilience also recognizes that the future may well be 

determined by unexpected changes, and emphasizes the ability to respond to surprises. We 

explore how resilience principles can be integrated into coral reef management.

Opportunities to Support Socio-Ecological Resilience to Mass Bleaching

Four successive conditions determine the ultimate impacts of mass coral bleaching following 

a regional heat stress event, and each can be a potential focus for management action; as 

illustrated in the figure below: 1) ‘bleaching resistance’ determines how corals within the area 

of a regional heat stress event are bleached; 2) if corals do bleach, ‘coral tolerance’ determines 

how corals either die or regain their zooxanthellae and survive; 3) if there is widespread coral 

mortality, ‘reef recovery’ determines how the coral reef ecosystem can recover and maintain 

the characteristics of a coral-dominated ecosystem; and 4) if the coral reef ecosystem remains 

degraded, ‘human adaptive capacity’ determines how human communities will experience 

negative socioeconomic consequences.

Each condition is influenced by a suite of factors that combine to determine the resilience 

or vulnerability of the system. Factors vary in how much they can be changed through 

management interventions, their relative influence, and the scale (coral colony, ecosystem, 

or human community) at which they are expressed. The following sections discuss these 

opportunities for management.
117

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

This diagram illustrates the possible opportunities for management intervention in coral reefs that 

are stressed by a coral bleaching event. Four conditions determine the final outcome: bleaching 

resistance; coral tolerance; reef recovery; and human adaptive capacity. Each is influenced by factors 

that can determine the resilience or vulnerability of the system. Factors that can be influenced by 

local management actions are colored blue. Factors that cannot be influenced are colored black, 

although these should be considered in the design and placement of management actions to enhance 

ecosystem resilience (adapted from 6).

Strong reef-based economy and society

Healthy coral

No bleaching

Protect resistence

determined by

Environmental factors

Intrinsic factors Bleaching Survival

Build tolerance

determined by

Coral health

Exposure 

Intrinsic factors

Promote recovery

determined by

Herbivory

Water quality

Biological diversity

Connectivity

Recovering 

ecosystem

Unhealthy

ecosystem

Support human adaptive capacity

determined by

Economic diversity

Supportive policy

Capital and technology

Human resource skills

Socioecomomic 

adaptation

Socioecomomic

decline

Time/effort/resources for recovery

Heat

Opportunities for 

management

Mortality
118

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Take advantage of resistant coral areas

When regional sea temperatures become unusually high, the effects on coral reefs are variable. 

Although many corals will bleach, some will not. What determines the ability of some corals 

or reef areas to resist bleaching? How can areas that are resistant be used to increase 

overall resilience of coral reef ecosystems to global climate change?

A combination of environmental and intrinsic factors determines whether corals eject their 

zooxanthellae or whether they resist bleaching during a regional heat stress event. Local 

environmental conditions can support resistance to bleaching by buffering how corals are 

exposed to unusually high sea temperatures or to sunlight. Three mechanisms can offer 

protection: shading; cooling; and screening. For example, mountains or cliffs on adjacent land 

offer shade to some patches of reef, as seen in the high islands of Palau. Some sites may have 

consistently cooler water as a result of upwelling or proximity to deep water. Sediment and 

organic matter in turbid waters seems to support coral resistance to bleaching by screening 

out sunlight; however, unnaturally turbid conditions can also seriously stress corals, thereby 

undoing any benefits. An additional environmental mechanism providing bleaching resistance 

is flushing. Strong currents may remove toxins that are the physiological trigger for bleaching, 

thereby helping corals cope with warmer conditions (7). 

Intrinsic factors that influence resistance to bleaching at the colony level include the individual 

history and genetic composition of the coral and its symbiotic zooxanthellae. This translates 

to important differences in the bleaching susceptibility of different coral communities. For 

example, massive, boulder-shaped corals (such as Porites and Favia) tend to be more resistant 

to bleaching than branching and plate forming corals (such as Acropora and Pocillopora). 

Corals also have some ability to acclimatize to heat and light stress if they are able to survive 

stressful conditions. Past exposure of coral colonies or communities to stressful conditions 

can lead to an increased resistance to future bleaching events. The ecological significance of 

this mechanism is still being examined, because acclimatization of colonies is often short-lived 

and acclimatization at the community level is often a result of the less resistant corals being 

lost (3). 

Coral reef areas that are naturally resistant to mass bleaching can be incorporated into the design 

and placement of management initiatives to enhance the overall resilience of the ecosystem. 

Some consideration has been given to the feasibility of methods for increasing the resistance 

of other reef areas to bleaching. Such strategies are unlikely to be practicable or cost effective 

at sufficiently large spatial scales to provide meaningful protection to ecosystems. However, 

it may be possible to shade, screen, or cool high-value (small) tourism sites to increase their 

bleaching resistance. These strategies are currently experimental and have the potential for 

unwanted side effects. They are probably best accomplished through partnerships between 

industry, scientists, and managers.

Build coral tolerance to mass bleaching

When corals lose their zooxanthellae and bleach, they are not dead. Some bleached corals will 

survive the heat stress event and regain their zooxanthellae populations; however, corals that 

bleach but survive the event are in a weakened state. They will probably have lower reproductive 

capacity, slower growth rates, and greater susceptibility to disease. The ability to survive 

bleaching events is significant in terms of recovery time. While it may take months or years for 
119

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

corals to recover from the sub-lethal effects of bleaching, it takes years to decades for reefs to 

recover after high coral mortality. Therefore, promoting coral survival during bleaching events 

is a particularly efficient focus for management. What allows some corals to be tolerant to 

mass bleaching? Can management actions be taken to build tolerance and minimize the 

impacts of mass bleaching events?

Coral health prior to exposure to heat stress may be the most important factor influencing 

colony survivorship during bleaching events. Most corals rely heavily on the energy provided 

by their zooxanthellae, and bleaching effectively robs them of their main energy source. As 

a result, corals in a bleached state are beginning to starve, and their ability to endure this 

hardship is likely to be important in determining whether they survive. Like many animals, 

corals store surplus energy as lipids (fats); corals in good condition have relatively high lipid 

levels, providing a buffer against periods of low energy supply. For this reason, it is thought that 

the condition of a coral at the time it bleaches may play a crucial role in determining whether 

it will survive the period of starvation that follows. Conversely, chronic or acute stresses (such 

as water pollution or anchor damage) that negatively affect coral condition could increase the 

risk of corals dying of the additional stress from bleaching (1). Therefore, reducing localized 

stressors is an important strategy to help corals survive bleaching events.

Some corals, especially species adapted to turbid environments, rely heavily on food particles 

captured from the water column (heterotrophy) to supplement their energy requirements. 

These corals may be less dependent on the energy provided by their zooxanthellae and thus less 

prone to starvation during a bleaching event. A better understanding of coral nutrition could 

help managers identify tolerant coral communities, allowing them to be incorporated into 

networks of refugia to enhance overall ecosystem resilience. 

Coral health and heterotrophy help increase coral tolerance to bleaching when the heat stress 

causing a bleaching event is moderate. Heat stress above a critical temperature threshold, 

however, causes direct physiological damage to corals, exceeding any nutritional factors and 

leading to death. Both environmental and intrinsic factors are important in determining the 

extent to which this happens. Thus, local environmental factors have an important influence 

on the amount of heat stress to which a coral is exposed. Similarly, intrinsic factors, such as 

genetics, influence the threshold temperature at which a coral dies; some species are able 

to tolerate higher temperatures than others. These factors contribute to patterns of natural 

tolerance that can be built into management planning. 

Promote coral reef recovery 

The rates at which corals can adjust to increases in heat stress are widely considered to be too 

slow to keep pace with even conservative climate change projections (Chap. 2). As a result, 

it is unlikely that coral reefs will continue to exist in their current condition. Instead, they 

will increasingly be in a state of recovery. What factors encourage successful ecosystem 

recovery after mass bleaching events or when other stresses associated with climate change 

cause high levels of coral mortality? What management actions can be taken to restore or 

maintain these factors?

Coral reefs will not necessarily recover to become the same types of reefs they were prior to 

being severely damaged. The goal in managing for resilience is to have a recovery process 
120

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

that maintains vital functions and processes, even if the coral reef itself looks quite different 

from its pre-disturbance state. Ecosystem condition, biological diversity, and connectivity all 

contribute to ability of the ecosystem to recover to a coral-dominated system, rather than 

shifting to an algal-dominated state.

Reefs suffering high coral mortality require a long recovery process of recolonisation by 

coral larvae and asexual reproduction (such as fragmentation) by surviving corals. Successful 

recruitment depends on many conditions. These include the presence of ‘source’ reefs to 

generate new larvae, good water quality that allows spawning and recruitment to succeed, and 

both strong herbivore (plant/algae eaters) populations and good water quality to ensure there 

is suitable clear coral rock available for new coral recruits. 

High biological diversity supports ecosystem recovery by increasing the chance that vital 

functions will still be performed despite some degradation of the system. When a diversity of 

species fulfill a function (for example, branching corals providing habitat for small fish), the 

loss of a single species will not lead to loss of the function. This ‘functional redundancy’ is a 

major quality of resilient systems. A system is less prone to collapse when crucial functions are 

performed by multiple species that respond differently to stress or disturbance events (called 

response diversity). 

Connectivity plays a central role in determining the capacity of a system to recover or reorganize 

following a disturbance, by influencing the likelihood that damaged reefs will be replenished 

from ‘seed’ reefs or refugia. Much of the connectivity in reef ecosystems depends on intact 

and healthy non-reef habitats, such as inter-reef hard bottom communities, mangroves, or 

seagrass beds. These non-reef habitats are particularly important to maintain and regenerate 

populations, and they will become increasingly critical as reef systems spend more time in 

recovery mode. 

There is ample evidence that coral ecosystems in good condition will recover from coral 

mortality more successfully than degraded reefs. Healthy reefs are better able to provide the 

conditions required for the recruitment, survival, and growth of new corals after established 

corals have been killed by bleaching. Good water quality, an abundant and diverse community 

of herbivorous fish, and high coral cover are vital aspects of ecosystem quality that facilitate 

recovery. Therefore, management of local fisheries, water quality, and tourism strongly 

influence the rate and success of recovery and future coral reef resilience. 

Support human adaptive capacity

In addition to supporting ecosystem resilience, actions can be taken to support the human 

communities that depend on coral reefs, such as fishers and tourism operators. There may be a 

question as to whether it is appropriate for coral reef or marine protected area (MPA) managers 

to engage in supporting human adaptive capacity to the affects of climate change. Yet, it is 

important to recognize that changes in resource condition are likely to result in changes in 

the patterns of resource use. Engaging with stakeholders during this reorganization will allow 

managers to build alliances, and gain knowledge and influence to help in effectively adapting 

management regimes to the new circumstances. As climate change makes life less predictable 

for resource users and managers, such cooperative, adaptive approaches will be essential to 

maintain socioeconomic well-being and achieve responsive, effective natural resource planning 

and management.
121

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

People’s ability to adapt to degraded coral reefs will depend on their own skills, resources, 

attitudes, and how their livelihoods are dependent on good coral reef condition, as well as the 

broader socioeconomic context in which they live. Resource users who have good skills for 

planning, learning and reorganizing, good financial and social resources, and confidence in 

their abilities and prospects are likely to be more resilient. Further, meaningful involvement 

in decision-making on natural resource management can increase user confidence and, 

concurrently, social resilience to changes in resource access resulting from the impacts of 

coral bleaching or through changes in management arrangements (4).

Resource dependency and broader socioeconomic issues will also influence how reef users can 

successfully diversify their activities when coral reefs become degraded. For example, recent 

studies suggest that dive businesses in population centers are likely to be more capable of 

responding to changes in reef quality caused by mass bleaching. These operators can shift from 

a marketing strategy of providing high quality dive sites for experienced divers to a business 

that provides instruction for new divers or even to boating experiences for non-divers. In 

comparison, mass bleaching may significantly affect businesses that take divers to remote 

locations, renowned for exceptional coral reef quality. Tourists may be unwilling to travel so 

far when high quality reefs are no longer on offer, and businesses in these remote locations may 

have limited options for business diversification (2).

As coral reef condition degrades, reef users will probably change their resource-use patterns; 

these changes will have important implications for coastal environmental quality. For example, 

dive operators may seek ways of establishing artificial reefs. As coral reef fisheries decline, 

interest and investment in aquaculture may increase. By engaging with stakeholders during 

this process, coastal managers will have the best chance of developing and implementing 

strategies that can meet goals for ecological as well as socioeconomic sustainability.

An Agenda for Action

Global climate change and mass coral bleaching are now considered among the greatest 

threats to the future condition of coral reefs and the services they provide. Although, it may be 

difficult to see how coral reef managers can respond to such global threats, a closer look at the 

discussion above reveals that opportunities for management action are present at each stage 

of the coral bleaching process. The strategies described below suggest ways to take advantage 

of these opportunities to support the socio-ecological resilience of coral reefs to global climate 

change. They also illustrate how managers can influence efforts to limit the rate and severity of 

global climate change. Mitigating climate change will require action by senior decision-makers 

working in climate change policy forums; however, coral reef managers have an important role 

to play in informing decision-makers and the general public about the affects of global climate 

policy on reefs. By taking action on these 5 strategies, coral reef managers will give reefs the 

best chance of responding to changes in global climate.

Strategy 1. Support efforts to limit sea temperature increases to 2oC and maintain ocean 

carbonate ion concentrations above 200 μmol kg-1. 

The rate and extent of warming will determine the window of opportunity for reefs to adjust 

through acclimatization, adaptation, and other ecological shifts. For example, fewer and less 

intense sea temperature anomalies will reduce the frequency and severity of bleaching events. 

Subsequently, this will allow more time for reefs to recover between events that do occur. 
122

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

These relationships mean that the effectiveness of broader efforts to reduce the rate and 

extent of global climate change will have significant implications for the effectiveness of local 

management initiatives. Implementing local management actions, such as those below, will 

enhance the resilience of coral reefs and ‘buy time’ to implement actions that will reduce 

the impacts of global climate change. However, if moderate or pessimistic projections for 

climate change eventuate, the resulting effects on reefs may overwhelm local management 

efforts aimed at maintaining coral-dominated systems.

The targets for action at a global level were articulated by coral reef managers and scientists 

at the 3rd International Tropical Marine Environment Management Symposium (ITMEMS) 

in October 2006. Conference participants adopted the ‘Coral Reefs and Climate Change’ 

statement, which called on senior decision-makers to “limit climate change to ensure that 

further increases in sea temperature are limited to 2oC above pre-industrial levels and ocean 

carbonate ion concentrations do not fall below 200 μmol.kg-1” (http://www.icriforum.org/

secretariat/japangm/docs/Coral_Reefs_Climate_Change_Brief.pdf). These recommendations 

were based on published projections of the temperatures at which severe bleaching events 

become an annual phenomenon and reef calcification rates become negative (Chap. 2). 

Coral reef managers can provide a powerful impetus for policy responses to climate change by 

generating their own compelling stories about the plight of reefs under their jurisdiction. Reef 

managers can document and communicate about the ecological and socioeconomic effects of 

mass coral bleaching, like those in the Caribbean during 2005. Two publications listed in the 

references that offer technical guidance on evaluating the impacts of mass bleaching are A 

Global Protocol for Assessment and Monitoring of Coral Bleaching (7) and A Reef Manager’s 

Guide to Coral Bleaching (5). The latter offers suggestions for communicating about mass 

coral bleaching with key audiences (e.g. decision-makers, stakeholders, colleagues, and the 

general public) before, during, and after bleaching events.

Strategy 2. Integrate resilience into Marine Protected Area networks. 

MPAs are important tools in coral reef management and can help achieve many of the 

management goals identified above. Traditionally, the principles of MPA selection, design, and 

management have not specifically addressed the threat of mass bleaching. Integrating the 

following considerations into existing or developing MPA networks will optimize the role MPAs 

can play in supporting coral reef ecosystem resilience to mass bleaching:

zx Refugia - Sites with natural resistance or tolerance to mass coral bleaching should 

be considered as sites warranting high protection in MPA networks. These ‘lucky’ 

areas can serve as source reefs that provide new coral larvae to more 

zx Representation and replication – To maximize biological diversity, MPA networks 

should aim to provide high levels of protection to sufficient areas of all habitat types. 

Rather than only protecting certain kinds of reefs, networks should aim to include 

representatives of all reef types and associated habitats at replicate sites. This is a 

risk-spreading approach that helps to account for the uncertainty associated with 

global climate change.

zx Connectivity – Incorporating knowledge about connectivity into the selection 

and arrangement of sites that will receive higher levels of protection can promote 

recovery after mass bleaching and other disturbances. Linking highly-protected 
123

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

areas along prevailing, larvae-carrying currents can replenish downstream reefs, 

increasing the probability of recovery at multiple coral reef sites. Non-reef areas 

adjacent to highly-protected reefs may also warrant increased protection because 

they can become staging areas for coral recruits as they move between reefs.

zx Good ecosystem condition – High coral cover, abundant fish populations, and good 

water quality are all elements of coral reef health that support recovery. Maintaining, 

enhancing, or restoring these valuable characteristics through management 

interventions are easier to achieve in some areas than others, because of various 

attributes of site location and use. In developing MPA networks, it is useful to 

consider whether additional management protection can be effective in maintaining 

these resilience-supporting qualities of ecosystem condition.

These principles are already being implemented into MPA networks around the world, 

including: Palau; the British Virgin Islands; Belize; the Seychelles; Yemen; and the Maldives. 

The Nature Conservancy’s Reef Resilience (R2) Toolkit (8) or website (www.reefresilience.org) 

has a more detailed discussion of how to identify resilient areas and incorporate these areas 

into MPA design. 

Strategy 3. Reduce local stressors to build coral tolerance to bleaching. 

Global climate change will add stress to coral reefs; therefore the removal of local stressors can 

help corals respond to these new, difficult conditions. Removing chronic local stressors caused 

by intensive tourism use, water pollution, or over-fishing can increase coral reef health and 

lipid levels. Corals with higher energy reserves are more likely to survive a bleaching event. 

Removal of acute stressors to corals during bleaching events is also likely to increase their 

ability to survive. Bleached corals are extremely stressed and have a reduced capacity for 

maintenance of essential functions, such as injury repair, resistance to pathogens, and defence 

against competitors. A stressed coral is less capable of recovering from physical injuries caused 

by careless snorkeling, diving, and boat anchoring. Repair of even minor tissue damage may 

be hindered for a stressed coral, thereby increasing the risk of infection or overgrowth by 

competing organisms. Acute increases in sediments and pollutants from coastal development or 

dredging will deliver additional stress to corals that must clear sediment from colony surfaces, 

wasting precious physiological resources. Bleached corals are also less effective at defending 

against invasion by microalgae or competing with macroalgae. These coral competitors benefit 

from increases in nutrients or reductions in the herbivorous fish populations that consume 

them. Therefore, management can promote coral survival during mass bleaching events by 

limiting damage from recreation, degraded water quality, and fishing pressures.

Strategy 4. Protect, maintain or enhance the conditions that promote ecosystem recovery. 

Coral cover, water quality, and herbivorous fish abundance are critical in determining reef 

recovery through their influence on processes, including: larval supply; availability of 

substrate for settlement; coral recruitment rates; and survival of juvenile corals. Traditional 

management strategies may be based on the assumption that reefs are likely to continue in 

relatively stable condition. As reefs spend more time in recovery mode, management targets 

may need to become more conservative to achieve satisfactory water quality, fish abundances, 

and coral cover. For example, water quality standards and fishery management regimes should 
124

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

be re-evaluated to determine if they are sufficient to maintain the conditions required for coral 

recruitment, which is the most vulnerable stage in the coral life cycle. Similarly, reef managers 

may need to re-direct or limit excessive diving pressure at sites where intense recreational use 

is reducing coral cover. 

Although the natural resilience of reef ecosystems will facilitate recolonisation and subsequent 

recovery of sites that suffer significant coral mortality, full recovery to pre-disturbance coral 

cover and diversity can take decades. Recovery can be further delayed, and even inhibited, if the 

natural resilience of the ecosystem has been reduced by other pressures, such as excess nutrients 

or sediments, habitat damage, or over-harvesting of crucial functional groups. Therefore, reef 

managers may wish to consider proposals to assist or accelerate natural recovery processes 

through active restoration. The diversity and scale of experimental restoration approaches 

used to date vary widely. They cover habitat modification, coral transplantation, species reintroduction, and enhancement of recruitment. The logistics, costs, and effectiveness of 

restoration activities, as well as any legal considerations, should be carefully examined before 

deciding on a course of action. 

Strategy 5. Engage stakeholders that rely on coral reefs. 

Managers can engage with stakeholders to support their ability to cope with the effects of 

global climate change by identifying potential socioeconomic and ecological vulnerabilities, 

communicating about potential impacts, and collaborating on response strategies. 

Assessments can be implemented to identify potential impacts and vulnerabilities to the coral 

reef, the people that depend on the reef, or both. A Reef Manager’s Guide to Coral Bleaching 

provides further technical guidance on implementing socioeconomic assessments, which can 

provide information, such as:

zx What are the types of social and economic effects likely to be experienced as a result 

of global climate change?

zx Who is likely to be affected?

zx What opportunities exist to minimize the direct effects of a bleaching event?

zx How can management responses be designed to minimize the impacts on reef 

users?

Managers can also increase socio-ecological resilience by predicting the start and severity 

of mass bleaching. These predictions not only allow managers to be the source of timely 

information about bleaching-risk, but also they increase trust and credibility with stakeholders. 

Social science research has found that resource users are more resilient and better able to cope 

with changes in resource management when they trust the decision-making process. NOAA’s 

Coral Reef Watch Program has developed three tools that analyze the likelihood of mass coral 

bleaching events (http://coralreefwatch.noaa.gov/). The book, A Manager’s Guide... provides 

guidance for interpreting the NOAA maps and describes other strategies for predicting mass 

bleaching.

Effectively communicating with target audiences about the past and future effects of mass 

bleaching and global climate change will promote awareness among stakeholders and 

provide information about potential effects to their livelihood. It will also increase support 
125

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

for management responses. This communication can occur passively, through industry 

newsletters, web sites, or media articles; or it can occur actively, through engagement in 

volunteer monitoring programs that provide early warnings about mass bleaching.

At the highest level of engagement, managers and resource users can collaboratively develop 

a climate change action plan. Such a plan could include strategies for: supporting ecological 

resilience; diversifying economic activities; enhancing human resource skills; making 

investments in capital and technology; or reworking related government policies. The Box 

below draws on recent discussions on the Great Barrier Reef, Australia, and is an example 

of strategies that could be included in an action plan to help a reef-based tourism industry 

respond to climate change. 

A collaborative action strategy to address the impacts of 

climate change on reef-based tourism

In November 2005, the Great Barrier Reef Marine Park Authority (GBRMPA) hosted 

a workshop about climate change for leaders of the Great Barrier Reef (GBR) marine 

tourism industry. Participants heard presentations from leaders in science, industry, and 

academia about the potential and expected impacts of climate change on the marine 

ecosystem, insurance costs, and tourist destination choices. Members of the marine 

tourism industry then assessed their vulnerability to climate change and devised possible 

responses and adaptation strategies through participatory breakout groups. 

Through workshop discussions, the participants concluded that:

zx There is now an overwhelming consensus that climate change is occurring as 

a result of human activity, and that it is one of the biggest threats to coral reefs 

worldwide.

zx The effects and changes to tourism operations as a result of climate change 

will be significant and are likely to be directly proportional to overall effects 

on the Great Barrier Reef.

zx There are a number of specific actions that the tourism industry can undertake 

to help it adapt to climate change. 

zx The challenges presented will be best addressed by working in partnerships, 

within the tourism industry, with other industries and with government 

agencies.

zx The key areas where actions can be taken are in marketing and communications; 

product development and business planning; and environmental and site 

adaptation.
126

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Conclusions

Although coral reef managers cannot directly mitigate climate change, they can take 

meaningful actions to support the socio-ecological resilience of coral reef ecosystems to 

climate change. This chapter offers guidance to reef managers on strategies for implementing 

resilience-based management as a response to coral bleaching and other threats associated 

with climate change:

zx Identify areas that are naturally resistant or tolerant to bleaching and protect them 

to act as refugia and as seed-banks to replenish more susceptible sites; 

zx Reduce local stressors to provide bleached reefs with the best chance to survive mass 

bleaching; 

zx Protect, maintain, or restore ecosystem condition, biological diversity, and 

connectivity to promote recovery at sites that experience high mortality; 

zx Engage with stakeholders about coming changes to build alliances, knowledge, and 

influence that can help in maintaining socioeconomic well-being and effectively 

adapt management regimes to the new circumstances; and finally, 

zx Inform climate change policy decisions by assessing the socioeconomic and 

ecological impacts of mass coral bleaching and conveying this information to senior 

decision-makers, colleagues, stakeholders, and the media.

A review of the actions identified by tourism operators at the forum, suggests six 

strategies that could be implemented through collaborative industry-governmentscience partnerships as a way of preparing for the impacts of climate change on reefbased tourism:

1. Better understand climate change implications for reef-based tourism:

A. Develop regional predictions of future trends

B. Assess business risks

C. Evaluate potential business adaptation strategies

D. Develop environmental management and engineering strategies

2. Integrate climate change into business planning and operations:

A. Implement strategies to maintain industry viability

B. Plan for extreme weather events

3. Reduce industry contributions to climate change:

A. Reduce greenhouse gas emissions

B. Offset air travel emissions

4. Support coral reef resilience to climate change:

A. Minimize physical impacts to the reef

B. Minimize negative impacts to water quality
127

Managing for Mass Coral Bleaching: Strategies for Supporting Socio–ecological Resilience

Acknowledgements

We wish to thank David Obura, Ove Hoegh-Guldberg, Jordan West, Rod Salm, Joanna Johnson, 

Nadine Marshall, Billy Causey, Roger Griffis, Naneng Setiasih, Lizzy McLeod, Colleen Corrigan, 

and Mark Drew for their continued encouragement and thoughtful conversations about how 

coral reef managers might meaningfully respond to the threat of climate change. 

Author Contacts

Heidi Schuttenberg, Sustainable Ecosystems, CSIRO and School of Earth & Environmental 

Sciences, James Cook University, Australia, Heidi.Schuttenberg@jcu.edu.au; Paul Marshall, 

Climate Change Response Program, Great Barrier Reef Marine Park Authority, Australia, 

P.Marshall@gbrmpa.gov.au

References:

This chapter draws on papers and reports listed below and in Suggested Reading; 

1. Buddemeier R, Kleypas J, Aronson R (2004). Coral Reefs and Global Climate Change: 

Potential Contributions of Climate Change to Stresses on Coral Reef Ecosystems. 

Pew Center on Global Climate Change. http://www.pewclimate.org/global-warmingin-depth/all_reports/coral_reefs/index.cfm 

2. Cesar H, Pet-Soede L, Westmacott S, Mangi S, Aish A (2002). Economic analysis of coral 

bleaching in the Indian Ocean-Phase II. In Linden O, Souter D, Wilhelmsson D, 

 Obura D (Eds) Coral Degradation in the Indian Ocean: Status Report 2002 (pp. 251-

262). CORDIO & University of Kalmar, Sweden

3. Coles SL, Brown BE (2003). Coral bleaching - Capacity for acclimatization and adaptation. 

In Advances in Marine Biology, 46, 183-223

4. Marshall NA, Marshall PA (2007). Conceptualising and operationalising social resilience 

within commercial fisheries in northern Australia. Ecology and Society, 12(1), www.

ecologyandsociety.org/vol12/iss11/art11 

5. Marshall P, Schuttenberg H (2006). A Reef Manager’s Guide to Coral Bleaching. Townsville: 

Great Barrier Reef Marine Park Authority, Townsville, Australia 163 pp. & 

 on www.coris.noaa.gov/activities/reef_managers_guide/welcome.html 

6. Obura DO (2005). Resilience and climate change: lessons from coral reefs and bleaching in 

the Western Indian Ocean. Estuarine Coastal and Shelf Science, 63(3), 353-372.

7. Oliver J, Marshall P, Setiasih N, Hansen L (2004). A Global Protocol for Assessment and 

Monitoring of Coral Bleaching. Bali: World Wildlife Fund.

8. The Nature Conservancy and Partners. (2004). R2 - Reef resilience CD ROM Toolkit: 

Volume 2.0. www.reefresilience.org 
129

Introduction

The 2005 coral bleaching event focused attention on the threat that continued ocean warming 

poses to Caribbean coral reefs. The most recent assessment by the Intergovernmental Panel on 

Climate Change (IPCC) concluded that human-induced climate change will cause a 1.8–4.0oC 

rise in global surface temperature by the end of the 21st century, with slightly less warming 

over most of the Caribbean. The challenge for climate scientists and coral reef ecologists has 

been to translate these more coarse projected changes in climate into impacts on coral reefs 

throughout the diverse Caribbean region. This chapter presents the most recent findings and 

assesses the overall threat of coral bleaching in the Caribbean over the coming century. 

Challenges in Predicting the Future

Global climate models provide the means to predict how Caribbean coral reefs will respond to 

future climate change. The models use basic physical and chemical principles to simulate the 

movement of heat, moisture and energy, through a three-dimensional grid representing the 

atmosphere, oceans and the land surface in response to natural (solar output, volcanic activity) 

and human (greenhouse gases, aerosols) heating forces. The simulation of future climates 

depends in large part on assumptions about demographic, economic and technological 

change over the 21st century. For example, a ‘business-as-usual’ emissions scenario envisions 

a continuation of current activities, like fossil fuel burning and consequent increases in 

greenhouse gases in the atmosphere, throughout this century. 

It is important when examining climate models to understand the difference between 

greenhouse gas emissions and atmospheric greenhouse gas concentrations. The concentration 

of greenhouse gases in the atmosphere depends on the rate of emissions and the rate at which the 

world’s ecosystems and the oceans take up or remove greenhouse gases from the atmosphere. 

Since the rate of carbon dioxide (CO2

) emissions currently exceeds the rate of uptake, stopping 

the rise in emissions each year is not enough to stop the build-up of atmospheric CO2. Stabilizing 

atmospheric CO2 concentrations and eventually global temperature will require reducing CO2

emissions well below today’s rate.

11. Predictions for the Future of the Caribbean

Simon Donner
130

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Scientists use sea surface temperatures (SSTs) from these models to estimate the frequency 

and severity of coral bleaching events under past, present and future climate scenarios. The 

NOAA Coral Reef Watch program uses the accumulation of ‘Degree Heating Weeks’ (equal to 

one week of temperatures that are 1°C warmer than the maximum monthly temperature the 

coral reef experiences in the average year) to predict the likelihood of coral bleaching in realtime. Observations indicate coral bleaching begins to occur when the degree heating week or 

DHW value exceeds 4°C-week and becomes severe when the DHW value exceeds 8°C-week. The 

preferred method for predicting coral bleaching from the more coarse data provided by global 

climate models is the accumulation of ‘degree heating months’. Similar to a degree heating 

week, a degree heating month or DHM is equal to one month of temperatures that are 1°C 

warmer than the maximum monthly temperature (e.g. the average temperature for September 

in much of the Caribbean). Historical data analysis has shown that DHM values of more than 

1°C-month and more than 2°C-month are strong proxies for the lower and upper bleaching 

thresholds used by the NOAA Coral Reef Watch Program. 

The resolution of these climate model forecasts (the size of the grid cells in the computer’s 

picture of the world) is limited by the speed of computers and the complexity of the model. 

Although the resolution of climate models has improved in recent years, the size of model grid 

cells is still much larger than features of a coral reef. For example, most of the global climate 

models used in the most recent IPCC report have a horizontal resolution of only 1 degree of 

latitude by 1 degree of longitude (~100 km x 100 km). Therefore, the models cannot provide a 

direct representation of the complex bathymetry and hydrodynamics of many coral reefs.

Scientists studying climate change and coral bleaching have resolved the problem either by 

downscaling (using secondary models or statistical relationships to translate the climate model 

data to a specific location) or by studying large-scale events, like the 2005 coral bleaching 

event, that can be described directly by the global climate model itself. This work has provided 

a general picture of the expected effect of future climate change on the frequency and severity 

of coral bleaching in the Caribbean.

Coral Bleaching in the Future

The various studies on climate change and coral bleaching conclude that the majority of the 

Caribbean is expected to experience conditions that currently lead to coral bleaching (DHM > 

1 or 2°C-month) every 2 years, or more, within the next 20 to 50 years. 

Whether coral bleaching occurs at these thresholds will depend on the ability of different 

corals and their symbionts to adapt or acclimate to warmer water temperatures. The warming 

scenarios indicate that on the majority (>75%) of Caribbean reefs, corals and their symbionts 

will need to increase their thermal tolerance by 0.2-0.3°C per decade over the next 30-50 years 

to avoid coral bleaching occurring more than once every 5 years. On about 25% of the reefs, 

mostly in the north-eastern Caribbean and Lesser Antilles, corals and their symbionts may 

need to raise their thermal tolerance by twice that amount over the same time-frame.

This forecast for the next 50 years is not very sensitive to the particular future emissions 

scenario, for two reasons. First, greenhouse gases like CO2

 remain in the atmosphere for 

decades and even centuries. This causes a lag between the emissions of greenhouse gases and 

their mean effect on climate. Second, even if the world was determined to dramatically reduce 
131

Predictions for the Future of the Caribbean

These two model figures show the estimated frequency of low intensity coral bleaching events across 

the Caribbean, based on downscaling of results from the Hadley Centre’s HadCM3 climate model 

with more than 90% of Caribbean coral reefs expected to experience DHM > 1°C-month at least 

every 2 years or more in the 2030s and DHM > 2°C-month at least every 2 years by the 2050s. 

Greater warming is expected in the north-eastern Caribbean, including parts of Cuba, Florida and the 

Bahamas. In the most optimistic forecast, based on a climate model less sensitive to greenhouse gas 

emissions (PCM of the US National Center for Atmospheric Research), low intensity coral bleaching 

does not become a biannual event on Caribbean reefs until the 2050s.
132

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

greenhouse gas emissions, it cannot happen overnight. It will take time, for example, to build 

a new low-carbon energy generating infrastructure. Therefore, climate models show that the 

planet is ‘committed’ to much of the warming predicted in the ‘business-as-usual’ scenario for 

the coming decades. 

A recent examination of the role of past human activity in the 2005 coral bleaching event helps 

disentangle the effect of such ‘committed’ warming, of possible adaptation by corals and of 

possible efforts to control greenhouse gas emission, on the future of Caribbean coral reefs. By 

focusing on the average warming over the entire region of the 2005 ‘HotSpot’, it was possible 

to use climate models to assess the probability of the 2005 bleaching event occurring, with and 

without the effect of greenhouse gas emissions on the climate. 

This analysis shows that the 2005 event would be extremely rare, possibly as low as a 1 in a 

1000 year event, without the observed warming since the Industrial Revolution. The build-up 

of greenhouse gases in the atmosphere has increased the probability of an event like 2005 

by at least an order of magnitude, to a less than 1 in a 100 year event. Furthermore, the 

warming projected to occur over the next 20-30 years should make this once rare occurrence 

a biannual event. The result is similar in a ‘business-as-usual’ scenario (SRES A1b) and a lower 

emissions scenario (SRES B1), in which efforts to reduce emissions cause the concentration 

of greenhouse gases in the atmosphere to stabilize in the year 2100 at twice the pre-industrial 

level (about 560 part per million of CO2 in the atmosphere).

The picture, however, could change with some form of long-term adaptation by most corals 

and their symbionts. In the ‘business-as-usual scenario’, if most corals and their symbionts 

increase their thermal tolerance by 1.5°C, mass coral bleaching will not happen once every 

5 years until the latter half of this century. Therefore, if such adaptation is possible, it could 

postpone the occurrence of frequent damaging bleaching events by 30-50 years or longer. In 

the lower emissions scenario, mass coral bleaching will not happen more than once every 5 

years until the end of the 22nd century if corals are able to adapt by 1.5°C. 

Together, these findings indicate that an increase in thermal stress on Caribbean coral reefs in 

the next 20-30 years is inevitable because of ‘committed’ warming. However, the findings also 

show that some temperature adaptation by Caribbean corals and their symbionts could allow 

time to alter the path of future greenhouse gas emissions and avoid coral bleaching events like 

2005 from becoming dangerously common this century.

A small fraction of the warming projected by climate models is actually a result of efforts to 

decrease another type of atmospheric pollution. The loading of aerosols, from African dust, 

pollution and volcanic eruptions, can lower Caribbean temperatures by as much as 1-2°C in 

some years. For example, evidence indicates the eruption of the El Chicon volcano in 1982 

(Mexico) and the Mount Pinatubo volcano in 1991 (Philippines), may have protected the 

Caribbean from high SSTs and extensive coral bleaching. In both cases, the warming in the 

Caribbean caused by subsequent El Niño events was lower than expected because of high aerosol 

levels in the atmosphere. Today, the development of cleaner fuel and energy technologies (e.g. 

low sulphur content) and changes in African land cover in the future is expected to reduce 

aerosol levels and hence further increase regional temperatures. 
133

Predictions for the Future of the Caribbean

Implications for Coral Reef Health

 “... the Caribbean fits the profile of a vulnerable region: biodiversity is far lower than 

in the Indo-Pacific; it has been more vulnerable than the Indo-Pacific during past 

climate fluctuations; it is a relatively enclosed basin with a growing human population 

in its drainage area and abundant evidence of anthropogenic effects and terrigenous 

(e.g. runoff-related) influences; there are no other large-scale reef communities in the 

tropical Atlantic that can serve as refugia or sources of recolonization; and evidence of 

widely distributed reef stress has already been noted.” (Smith and Buddemeier 1992)

Climate change poses an existential threat to the already heavily disturbed coral reefs of the 

wider Caribbean. The conditions that currently cause coral bleaching events are expected 

to occur more frequently (every 2 years) within 20-30 years across much of the Caribbean, 

especially the northern Caribbean. Thermal adaptation by corals and their symbionts could 

spare many Caribbean reefs from catastrophic future bleaching events, by allowing time for the 

world to reduce greenhouse gas emissions and change the long-term climate forecast. 

The final effect of the projected increases in the frequency and severity of thermal stress events 

on individual coral reefs across the Caribbean will depend on the hydrodynamics of the reefs, 

the health of individual ecosystems, the degree of other direct human pressures, the structure 

of the coral community, and the adaptability of the individual corals. It will also depend on 

the response of corals to associated changes in ocean chemistry, hurricane activity and disease 

transmission. 

0%

20%

40%

60%

80%

100%

2000 2050 2100 2150 2200

SRES A1b (to 2100) SRES B1 (to 2200)

with 1.5°C adaptation

Years

This model of the frequency that maximum annual degree heating month (DHM), averaged 

over the 2005 Caribbean bleaching region, exceeds the upper bleaching threshold of 

2°C-month. The results are from the GFDL climate models under a ‘business-as-usual’ 

scenario (SRES A1b; 2001-2100) and lower emissions scenario (SRES B1; 2001-2200) 

in which atmospheric CO2 is stabilized at 560 ppm in the year 2100 scenario. The black 

line assumes no adaptation by corals and their symbionts; the blue line assumes 1.5°C 

thermal adaptation.
134

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Caribbean coral reefs subjected to the more frequent bleaching events projected for the future 

are likely to undergo shifts in community structure. This may already be occurring, with major 

losses of the Acropora coral species since the 1970s. Frequent coral bleaching events, especially 

when combined with direct human pressures like over-fishing, pollution and sedimentation 

are expected to keep both coral and fish species richness low and lead to more algal-dominated 

ecosystems. Aggressive reductions in greenhouse gas emissions and local marine conservation 

efforts are necessary to avoid the long-term degradation of Caribbean coral reef ecosystems.

Author Contacts

Simon Donner, Department of Geography, University of British Columbia, Vancouver, Canada. 

simon.donner@gmail.com 

References

Donner SD, Knutson TR, Oppenheimer M (2007). Model-based assessment of the role of humaninduced climate change in the 2005 Caribbean coral bleaching event. Proceedings of the 

National Academy of Sciences, 10.1073/pnas.0610122104

Donner SD, Skirving WJ, Little CM, Oppenheimer M, Hoegh-Guldberg O (2005). Global 

assessment of coral bleaching and required rates of adaptation under climate change. 

Global Change Biology, 11:2251-2265.

Gill JA, Watkinson AR, McWilliams JP, Cote IM (2006). Opposing forces of aerosol cooling and 

El Niño drive coral bleaching on Caribbean reefs, Proceedings of the National Academy 

of Sciences, 103:18870-18873.

Intergovernmental Panel on Climate Change (IPCC) (2007). Climate change 2007: The 

Physical Science Basis. Summary for Policymakers. Contribution of Working Group I 

to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. 

Available at http://www.ipcc.ch.

Smith SV, Buddemeier RW (1992). Global change and coral reef ecosystems. Ann Rev Ecol Syst 

23:89-118
135

12. Sponsoring Organisations, Coral Reef

Programs and Monitoring Networks

AFD - AGENCE FRANÇAISE DE DÉVELOPPEMENT

This French government agency contributes to the economic and social development of more than 80 developing 

countries and the French overseas departments and territories. Total commitments in 2005 were Euro 1601 

million. It is both a public establishment and a specialized financial institution, and is responsible for project 

funding operations as part of France’s official development assistance. AFD provides financial assistance for 

public and private projects in many sectors, including: water resources; finance; urban and rural development; 

infrastructure, energy and environment; and access to social services (health, education). AFD cooperates with 

other funding agencies e.g. the World Bank, European Investment Bank, the Asian Development Bank, the 

European Commission, and administers the French GEF Secretariat (French Global Environment Facility), 

which integrates environmental considerations within development programs. After the initial focus on 

renewable resources management (fisheries, forestry, rangelands) and terrestrial environmental programs 

(protected area management), AFD now includes marine ecosystems in its portfolio and launched the French 

Coral Reefs Initiative for the South Pacific (CRISP) in 2004. Contact: Dominique Rojat, AFD Paris; rojatd@afd.

fr; www.afd.fr.

AGRRA – ATLANTIC AND GULF RAPID REEF ASSESSMENT

International scientists and managers collaborate via AGRRA to determine the regional condition of reefs in the 

Caribbean and Gulf of Mexico using a rapid assessment protocol. AGRRA has provided baseline data on coral 

reef health by visual assessments of stony coral cover, mortality and recruitment, macroalgal index, Diadema

density, abundance and size of key fish families. Consistency among observers is obtained with training 

workshops. Between 1997 and 2004, AGRRA-sponsored surveys were made at 819 reef sites throughout the 

Western Atlantic: Bahamas, Belize, Bonaire, Brazil, British Virgin Islands, Curaçao, Cayman Islands, Costa Rica, 

Cuba, Dominican Republic, Jamaica, Mexico, Panama, Puerto Rico, St. Vincent, Turks and Caicos, US Virgin 

Islands, US Florida and Flower Garden Banks, Windward Netherlands Antilles, and Venezuela. Survey data (as 

Access files) and summary products (as Excel and ArcView files) are posted online at www.agrra.org. Special 

issue #496 of the Atoll Research Bulletin contains the results of the first 20 areas assessed and a synthesis of the 

early findings. Contact: info@agrra.org. 

ARC CENTRE OF EXCELLENCE FOR CORAL REEF STUDIES

The Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies was established in 2005 to 

build the scientific knowledge that underpins sustainable management of coral reef resources. Headquartered 

at James Cook University, the ARC Centre of Excellence fosters strong collaborative research links between its 

partners in 31 countries. A primary goal of the Centre is to develop and undertake reef research programs of 

international significance that transcend traditional disciplinary, institutional and geographic boundaries. The 

Centre’s researchers undertake fieldwork throughout the Indo-Pacific and Caribbean. The Centre’s goal is to 

build human capacity and expertise internationally. The ARC Centre is the worlds’ largest provider of graduate 

training in coral reef science, with over 100 graduate students from more than 20 countries. Research activities 

inform reef industries, governments, development agencies, and NGOs worldwide. The Centre’s website provides 

links to over 400 recent publications and a variety of educational material and research services. Contact: 

Terry Hughes, info@coralcoe.org.au; ARC Centre of Excellence for Coral Reef Studies, James Cook University, 

Townsville, Queensland 4811, Australia. www.coralcoe.org.au
136

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

CARICOMP - CARIBBEAN COASTAL MARINE PRODUCTIVITY PROGRAM

This network of Caribbean marine laboratories, parks and reserves has been operating since 1986 with the 

support of IOC-UNESCO, the Macarthur Foundation, and the U.S. Coral Reef Task Force. CARICOMP monitors 

long-term variation in ecosystem structure and functioning in coral reefs, seagrasses, and mangroves according 

to standardised protocols in relatively undisturbed sites. The network also responds to regional events such as 

coral bleaching events and hurricanes. The Caribbean Coastal Data Centre at the University of the West Indies 

in Kingston, Jamaica archives the data and makes them available. CARICOMP contributes data to ReefBase 

and initiated the GCRMN in the Caribbean. In 2000, CARICOMP designed and initiated several sub-regional 

research projects, including studies of larval linkages and coral diseases, related to long-term management and 

restoration of Caribbean coastal ecosystems. The CARICOMP program networks institutions in 16 countries: 

Bahamas, Barbados, Belize, Bermuda, Cayman Islands, Colombia, Costa Rica, Cuba, Dominican Republic, 

Jamaica, Mexico, Netherlands Antilles, Panama, Puerto Rico, Trinidad and Tobago, and Venezuela. Contacts: 

John Ogden, jogden@marine.usf.edu; Dale Webber, Centre for Marine Sciences, UWI, Jamaica, dale.webber@

uwimona.edu.jm; Marcia Creary, Caribbean Coastal Data Centre, Jamaica, Marcia.Creary@uwimona.edu.jm; 

www.uwimona.edu.jm/centres/cms/caricomp/.

CBD - CONVENTION ON BIOLOGICAL DIVERSITY

Biological diversity, the variability among living things and the ecosystems that support them, is the 

foundation upon which human civilizations have been built. Sustaining biodiversity, in the face of considerable 

threats from human activities, constitutes one of the greatest challenges of the modern era. The Convention 

on Biological Diversity (CBD), an international legally binding treaty, arose from the Earth Summit in Rio 

de Janeiro in 1992 and has 190 Parties—virtually universal participation. The objectives of the CBD are: the 

conservation of biological diversity; the sustainable use of its components; and the fair and equitable sharing 

of the benefits arising out of the use of genetic resources. The Convention sets out broad commitments by 

Parties to take action at the national level for the conservation and sustainable use of biological diversity. 

Since entering into force, the Parties have translated the Convention into programmes of work, including the 

Jakarta Mandate on marine and coastal biological diversity. The elaborated programme of work on marine and 

coastal biological diversity addresses coral-reef issues through specific work plans on coral bleaching as well as 

the physical degradation and destruction of coral reefs, including cold-water corals. Contact: Jihyun Lee, CBD 

Secretariat, Montreal, Canada, jihyun.lee@cbd.int or www.cbd.int

CI - CONSERVATION INTERNATIONAL

CI is a global, field-based environmental organisation that promotes the protection of biological diversity. 

Working in more than 30 countries over 4 continents, CI applies innovations in science, economics, policy 

and community participation to protect the Earth’s richest regions of plant and animal diversity. The Marine 

Rapid Assessment Program (RAP) of the Center for Applied Biodiversity Science at CI organizes scientific 

expeditions to document marine biodiversity as well as freshwater and terrestrial biodiversity hotspots, and 

tropical wilderness areas. Their conservation status and diversity are recorded using indicator groups (molluscs, 

corals and fish), and the results are combined with social, environmental and other ecosystem information to 

produce recommendations for protective measures to local communities and decision-makers. The main focus 

of Marine RAP surveys has been the ‘coral triangle’ in Southeast Asia, which contains the richest coastal and 

marine biodiversity in the world. Contact: Leah Bunce, Conservation International, 1919 M St. NW, Washington, 

DC 20036 USA; www.biodiversityscience.org and www.conservation.org, l.bunce@conservation.org

CORAL - THE CORAL REEF ALLIANCE

CORAL is a member-supported, nonprofit organization based in California that is dedicated to protecting the 

health of coral reefs by integrating ecosystem management, sustainable tourism, and community partnerships. 

By targeting marine recreation providers, coral park managers, and other community stakeholders, CORAL’s 

programs build cooperative solutions to the challenges facing coral reef destinations around the world. 

Training, technical assistance, and financial resources provide the basis for building cooperative management 

strategies, sustainable tourism, and community led conservation projects that improve the health of reefs and 

the sustainability of reef tourism. In addition, CORAL builds public awareness about coral reefs through various 

outreach programs, such as the highly acclaimed Dive In To Earth Day. Together, CORAL and its partners are 

working hard to keep coral reefs alive. Contact: Brian Huse, bhuse@coral.org; www.coral.org
137

CRTR - CORAL REEF TARGETED RESEARCH & CAPACITY BUILDING FOR

MANAGEMENT PROGRAM

This is a leading international coral reef research initiative that provides a coordinated approach to credible, 

factual and scientifically-proven knowledge to support coral reef management. The CRTR Program is a 

partnership between the Global Environmental Facility, the World Bank, the University of Queensland 

(Australia), the United States National Oceanic and Atmospheric Administration (NOAA), and approximately 

40 international research institutes and other third parties around the world. The CRTR Program is a proactive 

research and capacity building partnership that aims to lay the foundation in filling crucial knowledge gaps 

in the core research areas of coral bleaching, coral reef connectivity, coral diseases, coral restoration and 

remediation, remote sensing and modelling and decision support. Each of these research areas are facilitated 

by Working Groups underpinned by the skills of many of the world’s leading coral reef researchers. The CRTR 

also supports four Centres of Excellence in priority regions, serving as important regional centres for building 

confidence and skills in research, training and capacity building. For contact: The Project Executing Agency, 

C/- Centre for Marine Studies, The University of Queensland, St Lucia, QLD 4072 Australia, info@gefcoral.org: 

www.gefcoral.org. 

GCRMN - GLOBAL CORAL REEF MONITORING NETWORK

The GCRMN was formed in 1995 as an operational unit of ICRI. The GCRMN is in partnership with ReefBase, 

Reef Check and NOAA, which constitute the central direction. The GCRMN is sponsored by IOC-UNESCO, 

UNEP, IUCN, CBD, the World Bank, Reef and Rainforest Research Centre, WorldFish Center and the ICRI 

Secretariat and central coordination is supported by the US Government and UNEP. IUCN currently Chairs the 

Management Group of the GCRMN, and the Global Coordinator is hosted at RRRC and interacts closely with 

The WorldFish Center. The GCRMN seeks to encourage and coordinate three overlapping levels of monitoring: 

zx Community - monitoring by communities, fishers, schools, colleges, tourist operators and tourists 

over broad areas with less detail, to provide information on the reef status and causes of damage 

using Reef Check methodology and approaches;

zx Management - monitoring by predominantly tertiary trained personnel in Government environment 

or fisheries departments, and universities for moderate coverage of reefs at higher resolution and 

detail using methods developed in Southeast Asia or comparable methods; 

zx Research - high resolution monitoring over small scales by scientists and institutes currently 

monitoring reefs for research. 

Equal emphasis is placed on monitoring to gather ecological and socio-economic data, with manuals available 

for both. A major objective is to produce 2 yearly national, regional and global Status of Coral Reefs Reports, 

such as those that form the basis for this report. The GCRMN functions as a network of independent Regional 

Nodes that coordinate training, monitoring and databases within participating countries and institutes in 

regions based on the UNEP Regional Seas Programme: 

zx Red Sea and Gulf of Aden - Middle East assisted by the Regional Organisation for the Conservation 

of the Environment of the Red Sea and Gulf of Aden (PERSGA) Contact: Abdelelah Banajah, 

Abdelelah.Banajah@persga.org; or Mohammed Kotb mohammed.kotb@persga.org 

zx The Gulfs – the Persian/Arabian Gulf, Gulf of Oman and the Arabian Sea - assisted by Regional 

Organisation for the Protection of the Marine Environment (ROPME). Contact:Hassan Mohammadi, 

ropme@qualitynet.net; or Peyman Eghtesadi, eghtesadi@inco.ac.ir

zx Eastern Africa – assisting Kenya, Mozambique, South Africa and Tanzania operating through the 

CORDIO network in Mombasa. Contact: David Obura in Mombasa, dobura@africaonline.co.ke and 

Nyawira Muthiga, nmuthiga@wcs.org; 

zx South Western Indian Ocean Island States - coordinating Comoros, Madagascar, Mauritius, 

Reunion and Seychelles with assistance from the Global Environment Facility and Indian Ocean 

Commission. Contact: Jude Bijoux, j.bijoux@scmrt-mpa.sc or Rolph Payet, rolph@seychelles.sc 

Sponsoring Organisations, Coral Reef Programs and Monitoring Networks
138

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

zx South Asia - for India, Maldives and Sri Lanka with support from the CORDIO program of SIDA and 

IUCN. Contact: the Regional Coordinator in Colombo, Jerker Tamelander, jet@iucnsl.org or Arjan 

Rajasuriya, Arjan@Nara.Ac.Lk

zx South East Asia - for the ASEAN countries with assistance from the ICRAN project and the WorldFish 

Center, Penang Malaysia. Contact: Karenne Tun, Regional Coordinator, k.tun@cgiar.org or Chou 

Loke Ming, National University of Singapore, dbsclm@nus.edu.sg

zx East and North Asia - Japan is assisting these countries via the Ishigaki International Coral Reef 

Research and Monitoring Center, and the Nature Conservation Bureau in Japan. Contact: Tadashi 

Kimura, tkimura@jwrc.or.jp 

zx Southwest Pacific and Melanesia, for Fiji, Nauru, New Caledonia, Samoa, Solomon Islands, Tuvalu 

and Vanuatu coordinated through the Institute of Marine Resources, University of the South Pacific 

and support from Canada. Contacts: Ken MacKay mackay_k@usp.ac.fj or Ed Lovell for Reef Check 

(lovell@suva.is.com.fj);

zx Southeast and Central Pacific, the ‘Polynesia Mana Node’ for the Cook Islands, French Polynesia, 

Kiribati, Niue, Tokelau, Tonga and Wallis and Futuna coordinated in French Polynesia from the 

CRIOBE-EPHE Research Station on Moorea. Contact: Caroline Vieux, carolinev@sprep.org

zx Northwest Pacific and Micronesia, the ‘MAREPAC Node’ for American Samoa, the Marshall Islands, 

the Federated States of Micronesia (FSM), the Northern Mariana Islands (CNMI), Guam and Palau. 

Contact: the Palau International Coral Reef Center, Sebastian Marino, smarino@picrc.org; 

zx Hawaiian Islands – for US islands in the Pacific. Contact: Ruth Kelty, Ruth.Kelty@noaa.gov, or Mark 

Monaco, mark.monaco@noaa.gov, or Athline Clark, Athline.M.Clark@hawaii.gov

zx U.S. Caribbean – for U.S. territories and states of Florida, Flower Garden Banks, Navassa, Puerto 

Rico, and U.S. Virgin Islands. Contact Mark Monaco, mark.monaco@noaa.gov or www.coralreef.

gov; or John.Christensen, John.Christensen@noaa.gov.

zx Northern Caribbean and Atlantic region coordinated through the Caribbean Coastal Data Centre, 

Centre for Marine Sciences, Jamaica for the Greater Antilles to Bermuda. Contact: Loureene Jones, 

loureene@gmail.com or Marcia Creary Marcia.Creary@uwimona.edu.jm;

zx Mesoamerican Barrier Reef System for Mexico, Belize, Guatemala, Honduras. Contact: Noel Jacobs 

MBRS Project office, Belize, Jacobs_nd@yahoo.com; or Melanie McField WWF Mesoamerican Reef 

Program, mcfield@bt.,net

zx Eastern Caribbean, for the Organisation of Eastern Caribbean States (OECS), Trinidad and Tobago, 

Barbados, and French and Netherlands Caribbean Islands, coordinated by CANARI, with support 

from UNEP-CAR/RCU from St Lucia. Contact: Claude Bouchon, claude.bouchon@univ-ag.fr; Paul 

Hoetjes, paul@mina.vomil.an; Angie Brathwaite, abrathwaite@coastal.gov.bb

zx Southern Tropical America Node for Costa Rica, Panama, Colombia, Venezuela and Brazil via the 

‘Instituto de Investigaciones Marinas y Costeras’ (INVEMAR) with support from UNEP-CAR/RCU. 

Contact: Alberto Rodríguez-Ramírez betorod@invemar.org.co.

Central Coordination contact: Clive Wilkinson Global Coordinator clive.wilkinson@rrrc.org.au or David 

Souter, david.souter@rrrc.org.au at the Reef and Rainforest Research Centre Science, PO Box 772, 

Townsville, Australia; or Christy Loper, NOAA Silver Springs Maryland USA, Christy.Loper@noaa.gov; 

Jamie Oliver at WorldFish Center in Penang Malaysia (j.oliver@cgiar.org); or Gregor Hodgson, Reef 

Check Foundation Los Angeles, gregorh@reefcheck.org. 

ICRAN - INTERNATIONAL CORAL REEF ACTION NETWORK 

ICRAN was established in 2000 with funding from the United Nations Foundation (UNF). It is a global network 

of science and conservation organisations working to halt and reverse the decline in health of the world’s 

coral reefs. ICRAN was formed in response to a Call to Action by the ICRI, and supports the implementation, 
139

and regular review of ICRI’s Framework for Action. ICRAN has been working at the global, regional and local 

level in over 30 countries with a range of activities that focus on the prevention and mitigation of coral reef 

degradation through management, monitoring and public awareness actions. Recognising that reefs and 

people are inextricably linked, ICRAN works to build resource stewardship within communities by providing 

opportunities to develop the skills and tools needed to ensure the sustainable use, and the long-term vitality of 

coral reefs. Actions include alternative livelihoods, training, capacity-building, and the exchange and application 

of traditional knowledge, and current scientific, economic and social information. E-mail: info@icran.org; 

www.icran.org 

ICRI - INTERNATIONAL CORAL REEF INITIATIVE

The International Coral Reef Initiative (ICRI) is a unique public-private partnership that brings together 

governments, international organizations, scientific entities, and non-governmental organizations committed 

to reversing the global degradation of coral reefs and related ecosystems, such as mangrove forests and seagrass 

meadows, by promoting the conservation and sustainable use of these resources for future generations. Since 

its establishment in 1995, ICRI has been a driving force behind scientific, governmental and civil society efforts 

to protect coral reefs and related ecosystems. The ICRI approach is to provide a platform for information 

sharing, as well as mobilize governments and a wide range of other stakeholders in an effort to improve 

management practices, increase capacity and political support, and share information on the health of these 

fragile ecosystems. In particular, ICRI aims to catalyse action that will: improve management practices; 

increase capacity and political support; and share information on the health of these ecosystems. ICRI has 

also designated 2008 as the International Year of the Reef (information: www.iyor.org). The ICRI Secretariat 

is currently hosted by the Governments of Mexico and USA, with an office based at UNEP in the UK; for more 

information, see www.icriforum.org and to contact the ICRI Secretariat, icri@unep-wcmc.org.

IFRECOR - FRENCH CORAL REEFS INITIATIVE

IFRECOR is the national programme for coral reefs in French tropical overseas territories. IFRECOR, launched 

in 1999 by the Ministries of Environment and Overseas Territories, developed a National Coral Reef Action Plan 

to be coordinated by a secretariat in the two Ministries. A national steering committee contains members of 

parliament, other ministries, social and natural scientists, and NGOs to recommend tasks under the plan. The 

IFRECOR budget was Euro 2 million over the last 4 years for activities within the 7 French overseas territories 

with coral reefs. Each territory has a local committee of stakeholders to implement coral reef management. 

IFRECOR has been successful in raising public awareness of the importance of coral reefs, establishing a French 

coral reef monitoring network, exchanging coral reef experiences between overseas territories, promoting 

sustainable uses, involving local communities, and conserving coral reefs. IFRECOR promotes French scientific 

and technical knowledge at international levels, encourages the participation of French coral reefs specialists 

in research, assists in developing and managing coral reefs in other countries, and participates in international 

coral reef monitoring. Since its establishment, IFRECOR, has catalysed an increasing the commitment by 

government and overseas territories to protect coral reefs and designate MPAs. The next IFRECOR steering 

committee meeting will be in Guadeloupe, FWI in April 2008. Contact: Bernard Salvat, Ecole Pratique des 

Hautes Etudes, Université de Perpignan, France, bsalvat@univ-perp.fr

IOC/UNESCO - INTERGOVERNMENTAL OCEANOGRAPHIC COMMISSION

The IOC was established under the auspices of UNESCO in 1960 to provide Member States of the United Nations 

with an essential mechanism for global cooperation in the study of the ocean. For more than 15 years, the 

IOC has sponsored international research and observation programmes aimed at management of coral reef 

ecosystems and, more recently, the impacts from climate change and ocean acidification on reef systems. IOC, 

with UNEP, IUCN and the World Meteorological Organization formed the Global Task Team on Coral Reefs 

in 1991 to develop global coral reef monitoring, which was the precursor to the GCRMN, with IOC, UNEP, 

IUCN, World Bank and the CBD now as co-sponsors. The IOC also collaborates with other programmes within 

UNESCO dealing with coral reefs, including the World Heritage programme, the World Network of Biosphere 

Reserves, and the Coasts and Small Island Developing States programme. The GCRMN contributes data on 

coral reef health and resources to the Global Ocean Observing System. Contact: Henrik Enevoldsen, IOC 

Science and Communication Centre on Harmful Algae, University of Copenhagen, Oster Farimagsgade 2D, 

1353 Copenhagen K, Denmark. h.enevoldsen@unesco.org; www.ioc.unesco.org

Sponsoring Organisations, Coral Reef Programs and Monitoring Networks
140

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

IUCN- THE WORLD CONSERVATION UNION

Founded in 1948, IUCN brings 1035 States, government agencies and NGOs from 181 countries together in a 

unique global partnership to influence, encourage and assist societies to conserve the integrity and diversity of 

nature and to ensure that any use of natural resources is equitable and ecologically sustainable. Its contributions 

include generating conservation knowledge, setting standards, developing and applying conservation tools, 

building capacity, and improving policies and global governance. The secretariat is located in Gland, Switzerland, 

and there are 42 regional and country offices and 10,000 volunteer experts within 6 Commissions, including the 

World Commission on Protected Areas (WCPA) and the Species Survival Commission (SSC), which focus on 

particular species, biodiversity conservation and the management of habitats and natural resources. The IUCN 

Global Marine Program links the members to all IUCN marine activities, including projects and initiatives of the 

regional offices and Commissions. The program is anchored in IUCN Headquarters, with most of the technical 

staff in regions with significant marine constituencies and issues. IUCN is a founding member of the GCRMN 

and the Head of the Marine Programme is the current Chair of the Management Group. Contact: Carl Gustaf 

Lundin, Global Marine Program IUCN - The World Conservation Union, Rue Mauverney 28, CH-1196 Gland, 

Switzerland, Marine@iucn.org

ISRS - INTERNATIONAL SOCIETY FOR REEF STUDIES

ISRS, founded in 1980, is the leading organisation for professional scientists, managers, and students of coral 

reef studies, with a projected membership in 2008 of more than 1000 from 60 countries. The Society promotes 

the production and dissemination of scientific knowledge and understanding of coral reefs, both living and 

fossil. It prints and distributes the journal Coral Reefs and the newsletter Reef Encounter, and offers major 

research awards and travel support for students. ISRS also assists institutions in developing countries to 

enhance their library resources. The Society awards the prestigious Darwin Medal for major contributions to 

coral reef studies, and coordinates and assists host countries with the quadrennial International Coral Reef 

Symposium, which it co-sponsors. Contact: Richard Aronson, President: raronson@disl.org; www.fit.edu/isrs/

NCAR - National Center for Atmospheric Research.

NCAR is a federally funded research and development center sponsored by the National Science Foundation. 

NCAR scientists collaborate with university colleagues to study climate, air chemistry, storms and basic 

weather processes, the Sun and its effects on the Earth, and how human activities affect and are affected by 

the atmospheric environment. NCAR also provides computing and observing services to researchers working 

in areas related to the atmosphere. The NCAR Institute for the Study of Society and Environment conducts 

research on the ecological and societal impacts of climate and weather, including studies of coral reef ecosystem 

vulnerability to global warming, ocean acidification, and other aspects of climate change. Scientists study these 

interactions to improve projections of the impacts of climate on ecosystems and natural resources, and to assist 

in forward-looking management strategies. NCAR is managed by the University Corporation for Atmospheric 

Research, a not-for-profit consortium of universities. Contact: Lucy Warner, UCAR Communications, 3300 

Mitchell Lane, Boulder, CO 80301 USA, lwarner@ucar.edu; www.ncar.edu.

NOAA - NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION USA

NOAA is an agency of the Department of Commerce dedicated to enhancing public health and safety and 

promoting sound economic interests by researching and predicting weather and climate-related events and 

protecting the coastal and marine resources of the USA. NOAA is a steward of U.S. marine resources and cochairs the U.S. Coral Reef Task Force, which is responsible for coordinating U.S. government efforts to conserve 

coral reefs. The NOAA Coral Reef Conservation Program (CRCP) addresses priorities in the National Action Plan 

to Conserve Coral Reefs and the National Coral Reef Action Strategy such as mapping, monitoring, research, 

education and managing reef resources. The CRCP facilitates and supports partnerships with scientific, private, 

government and NGO groups at local, state, federal and international levels. The goal is to support effective 

management and sound science to preserve, sustain and restore valuable coral reef ecosystems. Contact: 

NOAA Coral Reef Conservation Program, 1305 East-West Highway, N/OCRM, Silver Spring, MD, 20910 USA; 

coralreef@noaa.gov; www.coralreef.noaa.gov.
Sponsoring Organisations, Coral Reef Programs and Monitoring Networks

141

RAMSAR - CONVENTION ON WETLANDS

The Ramsar Convention on Wetlands, was signed in Ramsar, Iran in 1971 and broadly defines ‘wetlands’ to 

include all ‘areas of marine water the depth of which at low tide does not exceed six metres’ (Article 1.1). In 

the designation of Wetlands of International Importance (Ramsar sites) it also explicitly allows the inclusion 

of ‘coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low 

tide lying within the wetlands’ (Article 2.1). Coral reefs are recognised as a category of marine and coastal 

wetlands in the Ramsar Wetlands classification. Specific guidance on the identification and designation of 

coral reefs is provided in Ramsar Wise Use Handbook 14, 3rd edition 2007 (available on: www.ramsar.org/lib/

lib_handbooks2006_e.htm). There are 63 designated Ramsar sites that include coral reefs, including important 

sites in Australia, Brazil, Costa Rica, Cuba, Djibouti, Ecuador, France (overseas territories), Guinea, Honduras, 

Islamic Republic of Iran, Mexico, Nicaragua, Philippines, South Africa, Thailand, The Netherlands (overseas 

territories), United Kingdom (overseas territories) and Venezuela, but many important coral reefs have yet to be 

designated as Ramsar sites, and a priority for further designation of coral reef Ramsar sites has been recognised 

by the Convention’s Contracting Parties. Contact: Nick Davidson, Deputy Secretary General, Ramsar Secretariat, 

Rue Mauverney 28, CH-1196 Gland, Switzerland; davidson@ramsar.org; www.ramsar.org/types_coral.htm; 

information on coral reef Ramsar sites at Ramsar Sites Information Service; www.wetlands.org/rsis/.

REEF CHECK FOUNDATION

The Reef Check Foundation is dedicated to research, education and conservation with respect to two ecosystems: 

tropical coral reefs; and California rocky reefs. With headquarters in Los Angeles and volunteer teams in more 

than 90 countries and territories, Reef Check works to create partnerships among community volunteers, 

government agencies, businesses, universities and other non-profits. Reef Check maintains 4 major initiatives: 

to educate the public about the value of reef ecosystems and the current crisis affecting marine life; to create 

a global network of volunteer teams trained in Reef Check’s scientific methods who regularly monitor and 

report on reef health; to facilitate collaborations that produce ecologically sound and economically sustainable 

solutions; and to stimulate local community action to protect remaining pristine reefs and rehabilitate damaged 

reefs worldwide. Contact: Gregor Hodgson or Cori Kane, PO Box 8533, Calabasas, CA 91372; rcinfo@reefcheck.

org; www.ReefCheck.org

RRRC - REEF AND RAINFOREST RESEARCH CENTRE.

The Reef and Rainforest Research Centre Limited (RRRC) was established in 2006 to implement the Australian 

Government’s Marine and Tropical Sciences Research Facility (MTSRF) in North Queensland. As the successor 

entity to the CRC Reef (Cooperative Research Centre) and the CRC Rainforest, the RRRC builds upon the 

knowledge base developed through the CRC to ensure that targeted, focused research is delivered to appropriate 

end-users and management agencies. The RRRC manages scientific projects that comprehensively address 

issues of concern for the sustainable use, management and protection of the Great Barrier Reef (GBR) and its 

catchments as well as the issued for the rainforests of the Wet Tropics, through the generation and transfer of 

world-class research and the sharing of knowledge. Great Barrier Reef research conducted through the RRRC 

includes studies into the impacts of climate change and destructive pest outbreaks on the coral reef systems, the 

ecological and socio-economic effects of the marine protected areas in the GBR, coastal zone risk and threats 

and advances in sustainable use of the GBR. Contact: Sheriden Morris, Sheriden.morris@rrrc.org.au; www.rrrc.

org.au

UNEP - UNITED NATIONS ENVIRONMENT PROGRAMME

The mission of UNEP is to provide leadership and encourage partnerships in caring for the environment by 

inspiring, informing, and enabling nations and peoples to improve their quality of life without compromising 

that of future generations. UNEP makes a particular effort to nurture frameworks and initiatives at the local, 

national, regional and global level which enhance the participation of governments and civil society - the private 

sector, scientific community, NGOs and youth - in working together towards sustainable utilisation of natural 

resources. The challenge before UNEP is to implement an environmental agenda that is integrated strategically 

with the goals of economic development and social well-being; an agenda for sustainable development. Contact: 

UNEP, PO Box 30552, Nairobi, Kenya; info@unep.org; www.unep.org
142

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

UNEP - CORAL REEF UNIT (CRU) 

The CRU is the focal point within UNEP and the UN system to guide and mobilize policies and actions to 

support the conservation and sustainable use of coral reefs to safeguard their biological and biodiversity 

functions, which provide goods and services for the benefit of people and the sustainable development of 

dependant communities. Co-located with other coral reef resources at UNEP-WCMC, the CRU works closely 

with UNEP divisions/programs and international partners such as the International Coral Reef Initiative (ICRI) 

and Operational Networks. CRU activities include: supporting international collaboration to reverse coral reef 

degradation; cooperating to promote the political understanding of the importance of coral reefs; reviewing and 

integrating information on international policies related to coral reefs; and promoting innovative partnerships 

to address new and emerging coral reef issues, such as cold-water coral reefs. Contact: Stefan Hain, UNEP Coral 

Reef Unit, 219 Huntingdon Road, Cambridge, CB3 0DL, UK; stefan.hain@unep-wcmc.org. 

UNEP – REGIONAL COORDINATING UNIT FOR THE CARIBBEAN ENVIRONMENT

PROGRAMME (UNEP-CEP)

The Caribbean Environment Programme (CEP) of UNEP helps nations protect the marine environment and 

promotes sustainable development in the Wider Caribbean Region (WCR). CEP is managed by and for the 

countries of the region under a legal framework they created in 1983, known as the Convention for the Protection 

and Development of the Marine Environment of the Wider Caribbean Region (Cartagena Convention) which 

is supported by three Protocols, on: biodiversity (SPAW); land-based sources of pollution (LBS); and oil spills 

response. The CEP works as a facilitator, educator, and catalyst to co-ordinate activities and build the capacity 

of all member governments to manage their coastal environments and build sustainable and coastal economies. 

The 28 member States and 8 Territories that created the CEP, encircle the Caribbean Sea and Gulf of Mexico. 

Contact: Nelson Andrade Colmenares, Coordinator, 14 – 20 Port Royal Street, Kingston, Jamaica, West Indies; 

rcu@cep.unep.org; www.cep.unep.org.

UNEP - WORLD CONSERVATION MONITORING CENTRE

UNEP-WCMC is the biodiversity assessment centre of UNEP with a major coral reef focus. This includes critical 

marine and coastal ecosystem mapping, a global database on marine protected areas, and the global distribution 

of threats, including coral disease. Reef associated ecosystems have been a major focus since the first Status 

of Coral Reefs of the World: 1998 report. UNEP-WCMC has published the World Atlases of Coral Reefs and 

Seagrasses, and work is underway to revise mangrove data into a new global atlas for publication in 2008. 

Future work at UNEP-WCMC will focus on a better understanding the value of ecosystem good and services, 

especially coral reefs and associated ecosystems, in marine protected areas; and the importance of ecosystem 

biodiversity to people. Contact: Kristian Teleki, One Ocean Programme, UNEP-World Conservation Monitoring 

Centre, 219 Huntingdon Road, Cambridge, CB3 0DL, UK; oneocean@unep-wcmc.org or www.unep-wcmc.org.

UNESCO WORLD HERITAGE CENTRE 

The UNESCO World Heritage Centre (WHC), based in Paris, was established to assure the Secretariat of the 

1972 Convention concerning the protection of the World Cultural and Natural Heritage (World Heritage 

Convention). The activities include assisting member states prepare World Heritage nominations, following 

the state of conservation of inscribed properties as well as providing financial or technical support from the 

World Heritage Fund or from extra-budgetary sources for the conservation of the sites. The WHC is working 

towards a more integrated approach towards marine World Heritage sites, and the recently established Marine 

Programme aims: to increase awareness of the Convention as a legal tool for achieving conservation of marine 

and coastal ecosystems; to contribute to improving the state of conservation of existing marine World Heritage 

sites; to promote nominations of marine properties including serial and transboundary sites; and to establish 

partnerships to build a network of support for marine World Heritage. Contact: Marc Patry, UNESCO World 

Heritage Centre, 7 place de Fontenoy, 75352 Paris 07 Sp, France; m. patry @unesco.org

USCRTF - UNITED STATES CORAL REEF TASK FORCE

The USCRTF was established by Presidential Executive Order in 1998 to lead U.S. efforts to preserve and 

protect coral reef ecosystems. The USCRTF, co-chaired by the Departments of Commerce and the Interior, 
Sponsoring Organisations, Coral Reef Programs and Monitoring Networks

143

includes 12 federal agencies responsible for coral reef conservation, 7 state and territory partners, and 3 freely 

associated states. The USCRTF adopted the U.S. National Action Plan to Conserve Coral Reefs in 2000, the first 

U.S. plan to comprehensively address the most pressing threats to coral reefs. The Action Plan identifies two 

fundamental themes for immediate and sustained action: understand coral reef ecosystems and the natural and 

anthropogenic processes that determine their health and viability; and reduce the adverse impacts of human 

activities on coral reefs and associated ecosystems. The USCRTF launched initiatives to help implement the 

Action Plan, including developing 3-year Local Action Strategies in each jurisdiction to address key threats to 

reefs. Contact: U.S. Coral Reef Task Force Secretariat, National Oceanic and Atmospheric Administration, Office 

of Response and Restoration, 1305 East-West Highway, N/ORR, Silver Spring, MD, 20910; www.coralreef.gov.

U.S. DEPARTMENT OF STATE

The State Department leads the United States in its relationships with foreign governments, international 

organizations, and the people of other countries. Through its diplomatic efforts, the Department is dedicated 

to creating a more secure, democratic and prosperous world for the benefit of the American people and the 

international community. Within the Department, the Bureau of Oceans and International Environmental 

and Scientific Affairs is responsible for advancing sustainable development and natural resource conservation, 

including actions related to coral reefs and coral reef ecosystems, through a wide variety of international treaties, 

organizations, initiatives and public-private partnerships. Contact: The U.S. Department of State, Bureau 

of Oceans and International Environmental and Scientific Affairs, Office of Ecology and Natural Resource 

Conservation, Room 4333, 2201 C Street N.W., Washington D.C., 20520; www.sdp.gov/sdp/initiative/icri. 

WORLD BANK – ENVIRONMENT DEPARTMENT

The World Bank is an international financial institution dedicated to the alleviation of poverty. The Environment 

plays a crucial role in determining the physical and social well being of people. While poverty is exacerbated 

by deteriorating conditions in land, water and air quality, economic growth and the well being of communities 

in much of the developing world, continues to depend on natural wealth and the production of environmental 

goods and services. As a result, the Bank is committed to integrating environmental sustainability into its 

programs, across sectors and regions and through its various financial instruments. Reducing vulnerability to 

climate change, improving people’s health, and enhancing livelihoods through protecting ecosystem services 

and the environment are the hallmarks of the Bank’s Environment Strategy. Support for coral reef conservation 

and sustainable use is consistent with this theme, as it potentially affects hundreds of millions of people around 

the world. The challenge for the Bank and its many partners in coral reef conservation, such as ICRI and 

GCRMN, will be to help communities capture the benefits from the sound management of coral reefs to meet 

immediate needs, while at the same time ensuring the sustainability of these vital systems for generations to 

come. For information on the Environment Department, contact: Marea Hatziolos, Environment Department, 

The World Bank, 1818 H St. NW, Washington, DC 20433 USA, Mhatziolos@worldbank.org; www.worldbank.org/

icm; www.gefcoral.org

WORLDFISH CENTER

Formerly known as ICLARM, it is committed to contributing to food security and poverty eradication in developing 

countries. The efforts focus on benefiting poor people, and conserving aquatic resources and the environment. 

The organisation aims for poverty eradication; a healthier, better nourished human family; reduced pressure 

on fragile natural resources; and people-centered policies for sustainable development. WorldFish Center is 

an autonomous, non-governmental, non-profit organisation, established as an international center in 1977, 

with new headquarters in Penang, Malaysia and the focus for international efforts to tackle the major aquatic 

challenges affecting the developing world and to demonstrate solutions to resources managers worldwide. 

Contact: PO Box 500 GPO, 10670 Penang, Malaysia. Jamie Oliver, l.oliver@cgiar.org; www.cgiar.org/iclarm/

WRI - WORLD RESOURCES INSTITUTE

WRI is assisting coastal resource management and coral reef protection by providing comprehensive 

information on threats to coral reefs, economic value of the goods and services and losses that will result from 

reef degradation. The regional projects are implemented in close collaboration with partners, following the 

more-detailed global Reefs at Risk analysis from 1998. Reefs at Risk in Southeast Asia was released in 2002 and 
144

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

Reefs at Risk in the Caribbean in 2004, with the specific goals to: 1. improve the information base on threats 

to, status of, and protection of coral reefs in a region, by collecting, improving, and integrating information; 2. 

model threats to coral reefs based on population and development patterns, land use change, and the location 

and intensity of specific activities that degrade coral reefs; 3. develop a geographic information system (GIS)-

based tool for local-level evaluation of development scenarios and related implications for coral reef health and 

economic value; 4. evaluate economic losses likely to result from coral reef degradation; and 5. raise awareness 

of human threats to coral reefs through wide dissemination of project results. All data (including GIS data 

sets) are on www.reefsatrisk.wri.org. WRI is currently working on economic valuation of coral reefs in the 

Eastern Caribbean and Belize. Contact: Lauretta Burke, World Resources Institute, Washington, DC 20002, 

USA: lauretta@wri.org or Emily Cooper, ecooper@wri.org.

WWF – ‘the global conservation organization’

WWF is one of the world’s largest and most experienced independent conservation organizations, with almost 

5 million supporters and a global network active in more than 100 countries. WWF’s mission is to stop the 

degradation of the planet’s natural environment and build a future in which humans live in harmony with 

nature, by: conserving the world’s biological diversity; ensuring that the use of renewable natural resources 

is sustainable and promoting the reduction of pollution and wasteful consumption. Using our global scope, 

credibility, and expertise, WWF’s Global Marine Programme develops and advocates solutions for sustainable 

fishing and the creation and management of Marine Protected Areas (MPAs). As part of our efforts to support 

well-managed fisheries and stop destructive fishing practices, WWF promotes economic incentives, consumer 

initiatives, and trade management measures that encourage sustainable fisheries. WWF has also been active in 

coral reef conservation since the early 1970s, carrying out over 100 related projects in more than 30 countries. 

Our work to redress the inadequate protection of our oceans, reefs and coasts involves; establishing and 

implementing a network of ecologically representative, well-managed MPAs; improving the management and 

reducing external threats, such as climate change, to MPAs. Contact: Helen Fox, helen.fox@wwfus.org or Lara 

Hansen, lara.hansen@wwfus.org, WWF, 1250 Twenty-Fourth Street, NW, Washington, DC 20037; www.panda.

org
145

13. Suggested Reading

Adger WN, Hughes TP, Folke C, Carpenter SR, Rockström J (2005). Social-ecological resilience 

to coastal disasters. Science, 309: 1036-1039.

Aronson RB, Precht WF, Macintyre IG, Murdoch TJT (2000). Coral bleach-out in Belize, Nature 

405, p. 36.

Aronson RB, Precht WF, Macintyre IG (1998). Extrinsic control of species replacement on 

Holocene reef in Belize: the role of coral disease. Coral Reefs 17:223-230. 

Brown BE (1997). Coral bleaching: causes and consequences. Coral Reefs 16: 129-138.

Buddemeier R, Kleypas J. Aronson R (2004). Coral Reefs and Global Climate Change: Potential 

Contributions of Climate Change to Stresses on Coral Reef Ecosystems. Pew Center 

on Global Climate Change. http://www.pewclimate.org/global-warming-in-depth/all_

reports/coral_reefs/index.cfm (Accessed 17 June 2007).

Burke L, Maidens J. (2004) Reefs at risk in the Caribbean. World Resources Institute, 

Washington, DC, USA, 80pp. 

CARICOMP (1997). Studies on Caribbean Coral Bleaching, 1995-96. In Lessios HA, Macintyre 

IE (eds.) in Proceedings 8th Coral Reef Symposium, Smithsonian Tropical Research 

Institute, Balboa, Panama, pp. 673-678.

Coles SL, Brown BE (2003). Coral bleaching - Capacity for acclimatization and adaptation. 

Advances in Marine Biology, 46, 183-223.

Edmunds PJ. (2002). Long-term dynamics of coral reefs in St. John, US Virgin Islands. Coral 

Reefs 21: 357-367.

Garzón-Ferreira J, Díaz JM (2003). The Caribbean coral reefs of Colombia. Pages 275-301. In: 

J. Cortés (Ed.) Latin America Coral Reefs, Elsevier Science.

Gattuso JP, Frankignouille M, Bourge I (1999). Effects of calcium carbonate saturation of 

seawater on coral calcification. Global Planetary Change 18, 37-47.

Goreau TJ, Hayes RM, Strong AE (1997). Tracking South Pacific coral reef bleaching by satellite 

and field observations. In Lessios HA, Macintyre IE (eds.), Proceedings 8th Coral Reef 

Symposium, Smithsonian Tropical Research Institute, Balboa, Panama, pp. 1491-1494. 

Hendee JC, Stabenau E, Florit L, Manzello D, Jeffris C (2006). Infrastructure and capabilities 

of a near real-time meteorological and oceanographic in situ instrumented array, and 

its role in marine environmental decision support. In: Richardson LL, and LeDrew 

EF, Editors, Remote sensing of aquatic coastal ecosystem processes. Kluwer Academic 

Press, pp 135-156.

Hoegh-Guldberg O. (1999). Climate change, coral bleaching and the future of the world’s coral 

reefs. Marine and Freshwater Research, 50(8), 839-866.

Hughes TP, Baird AH, Bellwood DR, Card M, Connolly SR, Folke C, et al. (2003). Climate 

change, human impacts, and the resilience of coral reefs. Science, 301(5635), 929.
146

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

IPCC (2007). Climate Change 2007: The Physical Science Basis. Summary for Policymakers. 

Contribution of Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change. 18 pp.

Kleypas JA, Buddemeier RW, Archer D, Gattuso JP, Langdon C, Opdyke BN (1999). Geochemical 

Consequences of Increased Atmospheric Carbon Dioxide in Coral Reefs. Science 284, 

118-120. 

Kikuchi RKP, Leão ZMAN, Testa V, Dutra LXC, Spanó S (2003). Rapid assessment of the 

Abrolhos Reefs, Eastern Brazil (Part 1: stony corals and algae). Atoll Research Bull., 

496:172-187.

Laboy-Nieves EN, Klein E, Conde JE, Losada F, Cruz JJ, Bone D (2001). Mass mortality of 

tropical marine communities in Morrocoy, Venezuela. Bulletin of Marine Science 68: 

163- 179.

Leão ZMAN, Kikuchi RKP, Testa V (2003). Corals and Coral Reefs of Brazil. Pages 9-52. In: J. 

Cortés (Ed.) Latin America Coral Reefs, Elsevier Science.

Manzello D, Hendee J, Stabenau E, Lesser M, Warner M. (submitted). Remote, hourly 

physicological monitoring of two reef corals during the 2005 Caribbean-wide bleaching 

event at Lee Stocking Island, Bahamas. Coral Reefs. 

Manzello D, Berkelmans R, Hendee JC (2007) Coral bleaching indices and thresholds for 

the Florida Reef Tract, Bahamas, and St. Croix, U.S. Virgin Islands. Marine Pollution 

Bulletin 54: 1923-1931

Manzello D, Brandt M, Smith T, Lirman D, Hendee J, Nemeth R (2007). Hurricanes benefit 

bleached corals. Proceedings of the National Academy of Sciences, U.S.A. 104: 12035- 

12039.

Manzello D, Hendee JC, Ward D, Hillis-Starr Z (2006). An evaluation of environmental 

parameters coincident with the partial bleaching event in St. Croix, U.S. Virgin Islands 

2003. Proceedings of the10th International Coral Reef Symposium, Okinawa, Japan, 

709-717.

Marshall PA, Baird AH (1999). Bleaching of corals in the central Great Barrier Reef: variation in 

assemblage response and taxa susceptibilities. Coral Reefs 19, 155-163.

Marshall NA, Marshall PA (2007). Conceptualising and operationalising social resilience within 

commercial fisheries in northern Australia. Ecology and Society, 12(1), [online] URL: 

http://www.ecologyandsociety.org/vol12/iss11/art11.

Marshall P, Schuttenberg H (2006). A Reef Manager’s Guide to Coral Bleaching. Townsville: 

Great Barrier Reef Marine Park Authority. Pp. 163 or on: www.coris.noaa.gov/activities/

reef_managers_guide/welcome.html 

Mayor PA, Rogers CS, Hillis-Starr, ZM. (2006). Distribution and abundance of elkhorn coral, 

Acropora palmata, and prevalence of white-band disease at Buck Island Reef National 

Monument, St. Croix, US Virgin Islands. Coral Reefs 25: 239-242. 

McClanahan T, Polunin N, Done T (2002). Ecological states and the resilience of coral reefs. 

Conservation Ecology, 6(2), 18. on www.consecol.org/vol16/iss12/art18.

McGrath TA, Smith GW (1998). The effects of the 1995/1996 Western Atlantic coral bleaching 

event on the patch reefs around San Salvador Island, Bahamas’, Rev. Biol. Trop., Supl. 

5, pp. 91-99.

Mumby PJ (2006). The impact of exploiting grazers (scaridae) on the dynamics of Caribbean 

coral reefs. Ecological Applications, 16: 747-769.

Nurse L, Moore R (2005). Adaptation to global climate change: an urgent requirement for small 

island developing states. RECIEL 14; 100-107. 

Obura DO (2005). Resilience and climate change: lessons from coral reefs and bleaching in the 

Western Indian Ocean. Estuarine Coastal and Shelf Science, 63, 353-372.
147

Suggested Reading

Reaser JK, Pomerance R, Thomas PO (2002). Coral bleaching and global climate change: 

scientific findings and policy recommendations. Conservation Biology 14; 1500-1511. 

Rogers CS and Miller J. 2006. Permanent ‘phase shifts’ or reversible declines in coral cover? 

Lack of recovery of two coral reefs in St. John, US Virgin Islands. Marine Ecology 

Progress Series 306:103-114.

Shein KA, Waple AM, Levy JM, Bourassa MA, et al. (2006) State of the Climate In 2005, Bulletin 

of the American Meteorological Society, 87(6): S1, 95 pp.

Sheppard C, Rioja-Nieto R (2005). Sea surface temperature 1871-2099 in 38 cells in the 

Caribbean region. Marine Environmental Research, 60: 389-396.

Souter D, Linden O (eds.) (2005) Coral Reef Degradation in the Indian Ocean Status Report 

2005. University of Kalmar, Sweden.

Spalding MD (2004). A Guide to the Coral Reefs of the Caribbean, University of California 

Press, Berkeley, USA, p. 256 

Spalding M, Ravilious C, Green EP (2001) World atlas of coral reefs. University of California 

Press, California, USA.

The Nature Conservancy and Partners (2004). R2—Reef resilience CD ROM Toolkit: Volume 

2.0. www.reefresilience.org.

Trenberth KE and Shea DJ (2006) Atlantic hurricanes and natural variability in 2005, 

Geophysical Research Letters, 33, L12704.

Webster PJ, Holland GJ, Curry JA, Chang H-R (2005) Changes in tropical cyclone number, 

duration, and intensity in a warming environment. Science, 309: 1844-1846.

West JM, Salm RV (2003). Resistance and resilience to coral bleaching: Implications for coral 

reef conservation and management. Conservation Biology, 17(4), 956-967.

Wilkinson CR (1999). Global and local threats to coral reef functioning and existence: review 

and predictions. Marine Freshwater Research 50: 867-878

Wilkinson CR (2000). World-wide coral reef bleaching and mortality during 1998: a global 

change warning for the new millennium? In: Seas of the Millennium: An Environmental 

Evaluation, Volume III, Global Issues and Processes, Sheppard C Ed. Elsevier, Amsterdam, 

p. 43- 57.

Wilkinson C (2004). Status of Coral Reefs of the World: 2004. Global Coral Reef Monitoring 

Network & Australian Institute of Marine Science, Townsville, 2 volumes, p. 553

Wilkinson C (2006). Status of coral reefs of the world: summary of threats and remedial action. 

In: Coral Reef Conservation, Eds. Côté IM, Reynolds JD. Cambridge University Press, 

p. 3-39.

Wilkinson CR, Buddemeier RW (1994). Global climate change and coral reefs: implications 

for people and reefs. Report of the UNEP-IOC-ASPEI-IUCN Global Task Team on Coral 

Reefs. IUCN (the World Conservation Union) Gland Switzerland: 123 pp.

Wilkinson C, Linden O, Cesar H, Hodgson G, Rubens J, Strong AE (1999). Ecological and socioeconomic impacts of 1998 coral mortality in the Indian Ocean: An ENSO impact and a 

warning of future change? AMBIO, 28: 188-196.

Wilkinson C, Souter D, Goldberg J (2006). Status of Coral Reefs in Tsunami Affected Countries: 

2005. Australian Institute of Marine Science and Global Coral Reef Monitoring Network, 

Townsville 154 pp.

Wilson SK, Graham NAJ, Pratchett MS, Jones GP, Polunin NVC (2006). Multiple disturbances 

and the global degradation of coral reefs: are reef fishes at risk or resilient? Global 

Change Biology, 12: 2220-2234.
148

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005

14. List of Acronyms

AGRRA Atlantic and Gulf Rapid Reef Assessment

AIMS Australian Institute of Marine Science

CARICOMP Caribbean Coastal Marine Productivity Program 

CATIE Centro Agronomico Tropical de Investigacion y Ensenanza

CBD Convention on Biological Diversity 

CI Conservation International

CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora

CORAL The Coral Reef Alliance

CSD Convention for Sustainable Development

EIA Environmental Impact Assessment

ENSO El Niño Southern Oscillation

GBR Great Barrier Reef

GBRMPA Great Barrier Reef Marine Park Authority

GCRMN Global Coral Reef Monitoring Network

GEF Global Environment Facility

GIS Global Information System 

ICAM Integrated Coastal Area Management

ICM Integrated Coastal Management

ICZM Integrated Coastal Zone Management

ICRAN International Coral Reef Action Network

ICRI International Coral Reef Initiative

IFRECOR ‘French Coral Reef Initiative’

IOC Intergovernmental Oceanographic Commission of UNESCO

ISRS International Society for Reef Studies 

IPCC Intergovernmental Panel on Climate Change

IUCN The World Conservation Union

MAB Man and the Biosphere site of UNESCO

MARPOL International Convention of the Prevention of Pollution from Ships

MPA Marine Protected Area

NCAR National Center for Atmospheric Research

NGO Non-Governmental Organisation

NOAA National Oceanic and Atmospheric Administration (of USA)

Ramsar International Convention on Wetlands

RRRC Reef and Rainforest Research Centre. 

SCUBA Self-contained underwater breathing apparatus

UNEP United Nations Environment Programme

UNEP-CEP Regional Coordinating Unit for the Caribbean Environment Programme 

UNESCO United Nations Educational Scientific and Cultural Organisation

UNF United Nations Foundation

USAID US Agency for International Development

USCRTF United States Coral Reef Task Force 

UV Ultraviolet radiation

WCMC World Conservation Monitoring Centre

WHS World Heritage Site

WRI World Resources Institute

WWF the global conservation organization
The World Bank