A recent study has uncovered a small area off the coast of Kenya and Tanzania harboring a vast array of ocean life. Labeled a jewel of biodiversity by researchers, the reef complex is located in a rare ocean cool spot that is helping to protect large populations of corals and marine mammals from the devastating impacts of climate change.

The region is a hotspot for conservation but has historically suffered from destructive fishing practices that were destroying reefs. Future plans for coastal development, including a port in northern Tanzania serving a new oil pipeline, and continued unsustainable fishing by national and international fleets, mean the hotspot may still be in peril.

“Coral sanctuaries are regions where reefs have the best chance to survive climate change.  Scientists are scouring the world’s oceans to find and protect them,” said the study’s author and lead WCS coral scientist, Dr. Tim McClanahan. “This area off the coast of Tanzania and Kenya is a small but vibrant basin of marine biodiversity. Our study shows that while warming waters may devastate surrounding reefs, this area could become an incredibly important sanctuary where marine species big and small will flock to find refuge from climate change. If well protected, this key transboundary marine ecosystem will remain a jewel of biodiversity for the entire East African coast.”

The newly-discovered ocean sanctuary is intimately connected to the shape of Eastern Africa.  Its deep coastal basin was formed thousands of years ago during deglaciation by runoff from Mt. Kilimanjaro and the Usambara mountains. Those deep water channels now help provide thermal stability to marine ecosystems, shielding them from the worst of global warming in a pocket of cool and unstressful waters. As waters in the Indian Ocean continue to experience more frequent and intense heat spells, this refuge could prove increasingly important as a habitat for East Africa’s unique marine fauna, including threatened sharks and rays. Pods of spinner dolphins congregate in these waters and produce spectacles for those lucky enough to encounter them. The elusive and very rare dugong is also known to inhabit the area but they are seldom seen, especially by marine scientists, and need to be evaluated for their status and conservation needs.

If protected, this region has the capacity to continue to provide immense value as a global tourism destination, a hotspot for biodiversity, and a critical source of sustainably derived food and cultural heritage for generations to come.

This study and related long-term efforts were completed by the Wildlife Conservation Society with generous support from Bloomberg Philanthropies, the Western Indian Ocean Marine Science Association’s (WIOMSA) Marine Science for Management Program (MASMA), the Pew Fellows Program in Marine Conservation at The Pew Charitable Trusts, The Tiffany & Co. Foundation, and the John D. and Catherine T. MacArthur Foundation.


For more than 70 years WCS has been underwater studying coral reefs. Today there is a global crisis for coral reefs facing pressures from climate change, pollution, unsustainable tourism, and destructive fishing. From Kenya to Belize, Mozambique to Cuba, WCS is conserving reef biodiversity hotspots and supporting communities who depend on reefs to survive. We currently work across 16 countries to protect coral reefs and ensure that they can continue to provide for the people and species that rely on them.