Coral Reef Diversity

Coral reefs are among the world’s most biologically diverse ecosystems

Making up less than one percent of the ocean’s surface area, coral reefs host more than 25% of all marine life. They also provide critically important ecosystem services on which people depend. Worldwide, tens of millions of people are directly dependent on reefs for food and livelihoods. Reefs also provide protection to coastal areas from storms, are a source of medicines and other useful goods, and generate significant revenue from fishing and tourism.

Coral species diversity & monitoring

Our sites in East Africa host a variety of coral reef types and a great diversity of species. With over 180 documented species, the reefs around Vamizi Island and the northern Quirimbas Archipelago, for example, host the highest coral species diversity outside of the Coral Triangle.

Both local and coral reefs worldwide, are increasingly impacted by factors including unregulated tourism, overfishing, pollution and climate change.. Understanding and monitoring the effects of such impacts is vital in order to mitigate their effects, and are a major focus of our efforts at each of our sites.

In partnership with scientists and students from local and international universities we conduct regular surveys of coral cover and condition, including studies documenting coral species diversity. Our surveys of coral bleaching, particularly at times of high risk when sea temperatures are higher than average, contribute to regional and international efforts to map the occurrence and extent of coral bleaching episodes. Such information helps scientists learn more about how these impacts affect coral reefs worldwide, and how we might best be able to address their negative consequences.

Reef fish monitoring

Regular surveys of reef fish abundance and community composition at each of our three island sites, add to our understanding of the diversity and health of our reef systems and how they change naturally and due to human stressors. At Vamizi Island, for example, several years of surveys conducted by our partners at Universidad Lurio, have demonstrated notable differences inside and outside the Vamizi Community Marine Sanctuary where fishing is prohibited. Similar surveys at Mnemba Island are shedding light on the impact of managing tourism at degraded reefs around the island, with a notable decline in reef health at several sites over time as unregulated tourism has increased.

Reef fish monitoring also includes identifying and monitoring fish spawning aggregation sites, which have been identified for several species at some of our sites for giant trevally, Napoleon wrasse, bumphead parrotfish, giant grouper and grey reef sharks.

Such knowledge is the foundation for planning and informing effective management of marine protected areas, and for conservation and awareness raising initiatives targeting particular species such as the threatened Napolean wrasse and bumphead parrotfish – both of which occur in good numbers around Vamizi Island.

Coral Reef Soundscapes

Passive Acoustic Monitoring, whereby high powered underwater microphones (hydrophones) are deployed beneath the sea surface, is a technique to remotely survey and monitor underwater sound allowing for the detection and monitoring of marine animals such as dolphins, whales, certain types of fish, coral reef health, and noise pollution.

Scientists have recently started using the technology to assess the health of coral reefs. Healthy, diverse reefs are noisy, with complex reef soundscapes reflecting the diversity found on a reef. In 2019, we commenced a pilot project to assess reef health around Vamizi Island with several hydrophones deployed at a number of sites. Every 6-8 weeks the units are collected and the data uploaded, before the hydrophones have their batteries replaced and are re-deployed. Read more about our Ocean Soundscapes projects here.


Learn more about our other projects…

Explore our activities at each of our different sites

Apex Predators

Using the latest tracking technology we study the movements, habitat use and behaviours of apex predators, including sharks and giant trevally, to inform conservation and the establishment & management of marine protected areas.

Community Development

Working in close partnership with coastal communities to build capacity, develop sustainable livelihoods, promote marine conservation education and train & employ Marine Community & Conservation Rangers.

Fisheries & Food Security

Many millions of people depend directly on marine resources in East Africa. Our work contributes to fisheries monitoring, promoting sustainable fishing practices & assessing the nutritional value of fish to people as reef ecosystems change.

Ocean Soundscapes

Listening in on ocean soundscapes using underwater microphones enables us to monitor the health of coral reef ecosystems, study the behaviour of iconic marine animals and assess the impacts of noise pollution.

Sea Turtles

Five species of sea turtles occur in the Western Indian Ocean, with our sites supporting important nesting areas for four of these. Our sea turtle nest monitoring projects on Mnemba and Vamizi Islands are amongst the longest continuously running programs in East Africa.

Seascape Mapping & Monitoring

Mapping habitats & multiple use zones & deploying environmental sensors at our sites provides vital information for marine scientists, & informs marine spatial planning and the establishment & management of marine protected areas.

Terrestrial Biodiversity

Islands have high conservation value for threatened & endemic plants & animals. Our work focuses on plants, birds, reptiles & mammals, including a unique sub-species of the Samango monkey and the Endangered Ader’s duiker.

Whales and Dolphins

Numerous whale & dolphin species occur at out sites in East Africa with our focus on regular surveys and monitoring & research of resident and migrating populations, including Humpback Whales, using passive acoustic monitoring (underwater microphones).