Tanzania’s Indian Ocean Coral Reefs in deep trouble
Some of Tanzania’s most important coral reef ecosystems are already suffering devastating impacts from climate change with severe consequences for nature, fish, tourism, and people’s livelihoods.
Black News 
Some of Tanzania’s most important coral reef ecosystems are already suffering devastating impacts from climate change with severe consequences for nature, fish, tourism, and people’s livelihoods.
Conservationists have issued this warning in Kenya, as global leaders, scientists, and environmentalists gather in the coastal city of Mombasa for the global Our Ocean Conference, being held in Africa for the first time.
The alert comes from conservation organization Wild Impact, whose Oceans Without Borders programme works to protect and restore coral reefs in Tanzania with long-term support from Tusk, a conservation charity based in the UK, increasing the impact of African-driven conservation initiatives.
The deeper you go the warmer it becomes
Recent monitoring around Mnemba Island in Zanzibar revealed the growing scale of climate-driven coral bleaching across the Western Indian Ocean.
Sea temperatures around the island reached as high as 31°C at depths of 30 meters in early 2024, triggering one of the most severe coral bleaching events ever recorded in the region.
Wild Impact documented coral mortality rates of between 60 percent and 70 percent, with some branching coral species suffering losses of up to 80 percent.
The event was part of the fourth-largest global coral bleaching event, which affected reefs in 52 countries.
“The reefs are telling us something important. We are seeing ecosystems under immense stress from temperatures that would have been considered extraordinary just a few years ago. Communities across East Africa are already feeling the impacts through declining fisheries and threats to tourism livelihoods. The decisions taken by governments, investors, and conservation leaders at this conference will help determine whether these ecosystems have a realistic chance of recovery.”
Dr Camilla Floros – Scientific and Programme Lead at Wild Impact.
Rising sea temperatures force corals to expel the algae that provide them with food and color, leaving them weakened, bleached, and often unable to survive.
As reefs decline, fish populations fall, coastal protection weakens, and communities that depend on fishing and tourism face increasing economic hardship.
The consequences extend far beyond the reef itself. As coral dies, fish that depend directly on live coral, particularly butterflyfish, are often the first to disappear.
The loss of coral also removes vital shelter and nursery habitat for young reef fish such as damselfish, wrasses, and parrotfish, leading to declines in their populations.
As these smaller fish become less abundant, larger predators, including groupers, snappers, and trevallies, also decline, triggering a ripple effect throughout the marine food web.
Over time, the entire ecosystem becomes less diverse and less productive, threatening fisheries, tourism, and the livelihoods of coastal communities that depend on healthy oceans.
The Western Indian Ocean coral reef ecosystems alone generate an estimated annual economic value of over US$20 billion and heavily support the livelihoods of the 220 million people who live along its coastlines.
“Across our African conservation network, many of our partners are observing the ever-growing impacts of climate change on both terrestrial and marine ecosystems. This makes support for locally led conservation efforts more important than ever. Coral reefs are essential ecosystems that support an abundance of marine life, and the scale of recent bleaching events is concerning. Wild Impact is adapting to these challenges by working with local people to help restore and protect these vital marine habitats, and there is hope. By building partnerships and developing community-led solutions, they are helping to create a more resilient future for people and wildlife alike.”
Chantal Migongo-Bake – Chief Conservation Officer at Tusk
The timing of this call for urgent action is particularly significant as the Our Ocean Conference (ouroceankenya.com) is being hosted in Africa for the first time.
The Western Indian Ocean contains some of the world’s most important marine biodiversity hotspots, yet many of these ecosystems are increasingly exposed to rising ocean temperatures, marine heatwaves, and extreme weather events linked to climate change.
Wild Impact’s Oceans Without Borders programme is responding through a combination of science-led restoration and community conservation efforts.
The programme is growing corals in underwater nurseries, deploying reef restoration structures to accelerate recovery, and developing innovative land-based coral “seed banks” to safeguard vulnerable coral species from future bleaching events.
The programme is also working with 14 coastal communities in Zanzibar to train local marine rangers who monitor reef health, support restoration efforts, and help protect marine ecosystems.
These community-led approaches are creating new conservation employment opportunities while strengthening long-term stewardship of marine resources.
Despite the devastating losses, there are signs of hope
Monitoring around Mnemba Island has recorded the emergence of new juvenile corals and the gradual return of fish populations in areas where restoration and protection efforts are underway.
Scientists believe reef recovery could accelerate significantly within the next two years if restoration efforts continue and local pressures such as overfishing are reduced.
However, conservationists caution that restoration alone cannot solve the problem.
As delegates meet in Mombasa to discuss the future of the world’s oceans, conservationists say the experience of Zanzibar provides a powerful reminder that climate change is no longer a future threat but a present reality for marine ecosystems across Africa’s coastline.
About Tusk
Tusk’s mission is to accelerate the impact of African-driven conservation. Since the charity was founded in 1990, it has generated £150 million to support the growth of over 250 local partner organizations and wildlife ranger teams in more than 25 African countries, enabling and empowering the conservation movement across the continent.
About Wild Impact’s Oceans Without Borders Programme
Wild Impact is an independent non-profit conservation organisation dedicated to empowering communities living alongside some of Africa’s most important wildlife and wilderness areas. Founded in 1992 as Africa Foundation, the organisation began its work with communities neighbouring the Munywana Conservancy in South Africa. Its mission is to ensure that local people benefit directly from conservation.
