Listening in on an Underwater Wonderland
Our oceans are naturally noisy places. Wind, waves, animals and humans all contribute to ocean soundscapes. Because visibility is limited and sound travels great distances underwater, many marine animals rely on sound to communicate. However, our increasing use of oceans, including for shipping, mining, recreational boating and construction, adds another layer of noise that may adversely affect marine ecosystems. Listening in on ocean soundscapes using a network of underwater microphones (hydrophones), in a process called Passive Acoustic Monitoring, enables us to monitor the health of coral reefs, study the behaviour of marine animals such as whales and dolphins, and assess the impacts of noise pollution.
Coral reefs are naturally noisy because of the great variety of life that abounds on them. In contrast, degraded reefs generally have less complex soundscapes. Although all reefs will vary in the sounds they produce depending on time of day, tidal cycle, season, and from place to place, understanding the unique acoustic signatures of reefs enables us to use reef soundscapes as a way to monitor the condition or health of reefs, and to investigate the potential impact of sounds on them made by human activities.
Passive Acoustic Monitoring can also be used to detect specific fishes and other reef animals. For example, on Vamizi Island we are trialling it to document the presence of bumphead parrotfish, an Endangered species whose numbers are declining at several of our sites. These fish are noisy eaters as they eat and crunch through corals using powerful teeth. These crunches can be picked up by hydrophones suggesting that they may be present in an area.
Whales and dolphins communicate, often over large distances, through singing or by making loud clicking sounds. Each species, and even different populations within a species, has a unique repertoire of sounds it makes. This makes it possible to use Passive Acoustic Monitoring as a way of detecting and surveying different species in a region.
Listen to a humpback whale singing as it swims past one of our underwater hydrophone stations off Vamizi Island, Mozambique.
Shipping, recreational and commercial boating, coastal development, mining and exploration and other industries, all generate artificial noise that are increasingly part of ocean soundscapes, particularly in coastal regions.
The impacts of such activities and changing soundscapes on the marine environment are still poorly understood. Our efforts aim to help better understand the extent of artificial noise and assess their potential impacts on seascapes and marine life at our sites.
Learn more about our other projects…
See what we're doing in all our different fields
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.
Working in close partnership with coastal communities to build capacity, develop sustainable livelihoods, promote marine conservation education and train & employ Marine Community & Conservation Rangers.
Coral Reef Diversity
With some of our sites hosting among the highest coral diversity outside the Coral Triangle, coral reef studies are a major focus of our work including documenting & monitoring coral, fish & invertebrate health, diversity & abundance.
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.
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.
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).