Global Reef Expedition Final Report

Citation: Global Reef Expedition Final Report. Carlton, R., Dempsey, A., Thompson, L., Heemsoth, A., Lubarsky, K., Faisal, M., and Purkis, S. Khaled bin Sultan Living Oceans Foundation, Annapolis, MD. Vol 15. (2021)

The Global Reef Expedition Final Report summarizes the findings from our 10-year research mission to survey and map coral reefs across the Atlantic, Pacific, and Indian Oceans as well as the Red Sea. The Expedition involved hundreds of research scientists from around the world, and became one of the largest coral reef research missions in history.

Coral reefs offer a variety of ecosystem services, including sustenance, economic opportunities, and protection from natural disturbances, as well as playing an essential cultural role for thousands of communities. However, globally, the extent of the world’s reefs is being degraded at an astounding rate. The coral reef crisis has led to substantial coral declines ranging from 40% in the Indo-Pacific to more than 80% coral loss in the Caribbean. To better understand the coral reef crisis, the Khaled bin Sultan Living Oceans Foundation (KSLOF) embarked on the Global Reef Expedition (GRE), the world’s largest coral reef survey and high-resolution habitat mapping initiative, to assess the status of Earth’s reefs during a period of time. Data collected on the expedition will help scientists and marine managers better understand the extent of the coral reef crisis and provide valuable baseline data that can be used in both local and large-scale conservation efforts. 

The expedition was conducted by KSLOF, a US-based nonprofit environmental organization dedicated to providing science-based solutions to protect and restore ocean health. Starting as early as 2001, the foundation conducted field research to survey and map coral reefs to aid in coral conservation efforts. These research missions culminated in the Global Reef Expedition, which brought together an international team of over 200 scientists, educators, photographers, and filmmakers who circumnavigated the globe surveying some of the most remote coral reefs in the world. This report presents findings from the intensive GRE field research, education, and outreach that took place from 2006-2015, and from this point forward, references to the GRE in this document reflect the findings from the work completed during this period. 

From 2006-2015, the GRE visited 16 countries and territories around the globe, starting along the Saudi Arabian Red Sea coastline, traveling throughout the Caribbean and tropical Pacific Ocean, and ending in the Chagos Archipelago in the Indian Ocean. Local representatives from the communities provided invaluable knowledge and helped us share our findings with the residents. Our team of scientists used standardized methods to map and assess the benthic and fish communities, allowing us to evaluate the reefs across large geographic areas. To better understand large-scale trends, we grouped data into three datasets: the Saudi Arabian Red Sea, the Caribbean, and combined data from the Pacific and Indian Oceans. 

The primary scientific goals of the expedition were to:

  1. Map and characterize coral reef ecosystems
  2. Identify the current status of and threats to the world’s reefs
  3. Examine factors that enhance a reef’s ability to resist, survive, and recover from major disturbance events such as bleaching, cyclone damage, and crown-of-thorns starfish outbreaks.

As the science team was conducting research, our team of educators worked in real time with communities to share discoveries. In turn, knowledge of how the local communities managed their marine resources was shared with the scientists at sea. Our photographers and filmmakers produced award-winning films to showcase the work and transport audiences to places they may have never otherwise seen. 

Mapping the World’s Reefs

Using high-resolution satellite imagery, KSLOF was able to map over 65,000 km2 of coastal marine habitats in 11 countries and territories across the globe. This mapping endeavor produced the most comprehensive atlas of ground-truthed high-resolution coral reef habitat maps. Two publications, the Atlas of the Saudi Arabian Red Sea Habitat and the Atlas of Shallow Marine Habitats of Cay Sal Bank, Great Inagua, Little Inagua, and Hogsty Reef, Bahamas, were released by the foundation and are freely available on our website. One of the most useful tools developed because of the mapping component of the GRE is the web-based World Reef Map. This is a global, online, interactive map that allows users to explore all the surveyed coral reefs. These maps continue to be used by scientists and managers to aid in management and conservation efforts globally.

Benthic Assessment of the World’s Reefs

KSLOF conducted nearly 8,600 benthic surveys at over 1,200 survey stations around the world. Globally, coral reef benthic communities varied by location. In the Red Sea, the highest mean (±S.E.) coral cover was in the Farasan Banks (29.4±13.4%) and the lowest was found in Ras Al-Qasabah (20.4±10.4%). Macroalgal cover was high in shallow locations in the Farasan Islands and nearshore reef flat communities in the Farasan Banks and parts of Ras Al-Qasabah, but in Al Wajh and Yanbu, crustose coralline algae and turf algae were the dominant algae groups observed. 

In all locations surveyed in the Caribbean, algae dominated the substrate, with a mean (±S.D.) of 65±14% across all locations. Macroalgae was the most abundant algae observed in all locations. Mean live coral cover for each country in the Caribbean ranged from <8% to 14%, with The Bahamas having the lowest live coral cover and St. Kitts and Nevis having the highest. 

In the Pacific and Indian Oceans, the benthic communities had high coral cover, and the algal communities were dominated by crustose coralline and turf algae. The reefs of the Gambier Archipelago in French Polynesia had the highest mean live coral cover (52±13%), followed by the Republic of Palau (49±16%) in the Pacific Ocean. The Chagos Archipelago in the Indian Ocean had a mean live coral cover of 40±16%. New Caledonia and the Cook Islands had the highest percentage of algae recorded but were both dominated by crustose coralline algae. 

Fish Assessment of the World’s Reefs 

Our fish experts conducted over 8,300 fish surveys across all locations to better understand the status of the world’s reef fish populations. Overfishing was evident in nearly every location we surveyed on the GRE. Some studies estimate that a baseline biomass threshold for reef fish should fall between 11 and 19 kg per 100 m2, and most locations fell at or below that threshold. Almost every location had few large commercially important fish, with most of the fish biomass instead composed of small fish in the lowest trophic levels. 

The fish of the Red Sea were diverse, but some species appeared to be depleted, including many top predators like sharks and groupers. The fish communities of the Red Sea had varying reef fish communities that were highly dependent on the benthic communities. Generally, the sharks and large groupers were rarely seen, and instead some of the largest fish seen on the reefs were parrotfish. 

The fish communities on Caribbean reefs had very low fish biomass, and most fish were herbivores. The Bahamas had the highest mean fish biomass (11±9.5 kg per 100 m2) and second-highest mean fish density (61±25 fish per 100 m2) in the Caribbean. Colombia had a higher mean fish density than The Bahamas but the second-lowest mean fish biomass (5.6±2.8 kg per 100 m2), showing the fish there were abundant but small. 

The fish communities of the Pacific and Indian Oceans varied greatly by location. The Tuamotu Archipelago in French Polynesia had the highest fish density (279±165 fish per 100 m2) and second-highest fish biomass (39±48 kg per 100 m2) of all locations surveyed in the Pacific and Indian Oceans. The Kingdom of Tonga had alarmingly low fish density (92±46 fish per 100 m2) and biomass (4.5±4.1 kg per 100 m2), the lowest of all locations surveyed in the Pacific and Indian Oceans. The highest fish biomass (42±20 kg per 100 m2) was found in the Galapagos Islands, which was due to the high number of sharks and other large top predators found at this location. 

Education on the GRE

The education and outreach teams launched several in-country programs to share the foundation’s knowledge about coral reefs with community members, traditional leaders, local teachers, and schoolchildren. In total, over 7,000 people attended coral reef seminars, community events, and ship tours in Jamaica, French Polynesia, Tonga, Fiji, and the Solomon Islands. The government and community seminars proved to be especially important. Not only was the foundation providing education about coral reefs, but also, we received valuable local environmental information from the participants.

Using Photography and Film to Bring the GRE to the Rest of the World

The M/Y Golden Shadow served as an incredible platform from which to photograph and record high-resolution footage in parts of the world that had never been recorded before. Using this footage, we were able to develop and broadcast our award-winning films, such as our 2015 Suncoast Emmy® winning film, Sharks of the Coral Canyon, to communities around the world. These films and photographs brought to life the research that we were conducting. We were able to bring the coral reefs that we were studying into living rooms and classrooms worldwide. 

Five Main Takeaways from the GRE

There were many things learned from our research on the Global Reef Expedition. Whether we were visiting some of the most remote untouched reefs or reefs being used by local communities, each one had a story to tell and added to our knowledge about the extent of the coral reef crisis. 

The five main takeaways from the GRE are: 

1) Swift action is needed to address climate change. Climate change is currently the biggest threat that the world’s reefs are facing. Coral bleaching and ocean acidification are a direct result of climate change, and regardless of the status of a reef, these two disturbances will have substantial impacts globally if climate change is not addressed.

2) Reef fish populations are being overexploited globally. One of the most significant findings from the GRE was that nearly every country we visited showed signs of overfishing. Almost all countries had predominantly small fish remaining, particularly in families fished for subsistence and commercial fishing. Most reef fish populations are unable to withstand the fishing pressure they are currently experiencing, and expansion and enforcement of fishing regulations is critical.

3) We need better management of acute reef disturbances. Both natural and human-induced disturbances are having a negative impact on coral reefs. Widespread coral mortality from crown-of-thorns starfish outbreaks was seen in Saudi Arabia, French Polynesia, Tonga, and the Solomon Islands, and we witnessed an active outbreak occurring in the Cook Islands. Most of the natural acute disturbances, such as tsunamis, storms, and crown-of-thorns starfish outbreaks, are hard to manage. Managing and relieving other reef stressors such as nutrient runoff and overfishing can help reefs recover from these acute disturbances. 

4) Marine Protected Areas (MPAs) work in conserving coral reefs. We were able to work in some of the world’s oldest and largest MPAs. Some countries we visited, such as Australia (Northern Great Barrier Reef), Palau, and New Caledonia, have large human populations utilizing the reefs and have prioritized establishing large protected and managed areas to conserve their nearshore reef systems. In nearly every instance, these reefs had the best coral and reef fish communities. Protecting remote reefs and using marine spatial planning to strategically place no-take, no-entry MPAs can help engender coral reef resilience. 

5) Collaboration with local communities has the biggest impact on reef conservation. In order to protect and conserve the world’s reefs, aggressive measures will need to be taken. One of the biggest takeaways from the GRE was that nearly every community we worked with around the world expressed, and continues to express, the want and need for conservation of its reef systems. Working directly with the communities, continuing education programs, sharing our findings, and expanding on their current management efforts has proven to be the most successful in conserving the reefs visited on the GRE. 

The GRE took place at a critical time, providing a baseline dataset that is being used by scientists and managers around the world to help battle the ongoing coral reef crisis. Over 100 peer-reviewed scientific papers, reports, and management plans have been published using data collected on the GRE. Our work has helped establish internationally recognized Marine Protected Areas and locally managed areas around the globe. Currently, our maps are being used in partnership with NASA to help map the remainder of the world’s reefs. These maps can be used to aid in conservation efforts at an even larger scope than the already expansive GRE. 

Drastic measures are needed to address the coral reef crisis. KSLOF hopes the findings in this report, as well as our many resources that resulted from the GRE, will be used by scientists, managers, and communities around the world to support their conservation efforts. This expedition would not have been feasible without the tireless work of our partners and everyone who participated on the GRE. The gracious financing and support from His Royal Highness Prince Khaled bin Sultan Abdulaziz Al-Saud made this work possible, and for that, we will be forever indebted. 


Global Reef Expedition Final Report

The Global Reef Expedition Final Report presents the Foundation’s findings from the Khaled bin Sultan Living Ocean Foundation’s entire Global Reef Expedition. 


Global Reef Expedition Final Report (15 MB PDF)

Global Reef Expedition Final Report – Single Pages (15 MB PDF)