Coral Reef Restoration

Coral Reef Ecosystem Expansion, Zanzibar

Coral reefs are the rainforests of the sea. These critically important ecosystems host more than 25% of all marine life.

In addition to this life-sustaining role, a decline in live coral cover also poses a significant threat to local livelihoods, food security, commercial and subsistence fisheries, tourism, and associated industries within the Blue Economy.

The pressures on Zanzibar’s reefs mirror those threats facing coral reefs around the world: increasing water temperatures resulting from climate change, tropical cyclones, destructive fishing practices, plastic waste, unregulated tourism and coastal development. In the face of these factors, what is the role of reef restoration? The Coral Reef Consortium explains it like this:

Coral reef restoration can help span the predicted gap between the present when existing coral populations are threatened with extinction, and a future ocean that is hospitable again to corals.

Beacon of hope

In September 2021, the Oceans Without Borders’ Mnemba Island Community & Conservation team started their intensive and comprehensive training course with Marine Cultures, an NGO supporting small-scale ecological aquaculture conservation projects in Zanzibar.

This partnership with Marine Cultures will have a broad reach: we will build on our shared experiences, integrating lessons learned from the OWB Coral Reef Restoration Project, and actively engaging local communities around reef restoration.

Through these close collaborations, we are working to restore the ecological integrity of our local Mnemba Island reefs, inform the management and protection of this marine conservation area, and ultimately support the sustainability of local reef fisheries.

An accessible and suitable area of a local reef, often referred to as the Mnemba House Reef, was selected as a living laboratory for the project. From an initial five coral tables used to cultivate the coral fragments, there are now 15, and it will soon be time to transplant successfully cultivated coral colonies onto degraded reef sections of the house reef.

At this crucial point, the funding to create a second reef site is exactly what is needed to reduce pressure on the Mnemba House Reef and encourage the new coral growth.

Coral for the Climate!

Coral Reef Ecosystem Expansion, Zanzibar

This additional reef restoration project, shaped around a community-owned artificial reef structure, is currently in the launch phase.

Not only will it reduce pressure on the Mnemba House Reef and support the newly transplanted corals, but it will also include the active participation of two communities, and have far-reaching benefits across research, education and the Blue Economy of Zanzibar.

The more variety of corals we cultivate, the better. This both preserves and promotes essential biodiversity in the reforestation of the reefs.

Marine Cultures
#Fact Snapshot
  • The Community & Conservation team dedicates three days a week to working underwater to tend the coral nursery
  • Coral fragments are collected from a variety sites around Mnemba Island
  • These coral fragments are known as Corals Of Opportunity (COO)
  • The GPS location of every fragment collected is recorded
  • Each fragment is glued using specialised Pratley Putty to a small cement disc, which is then added to the coral table
  • To ensure healthy growth, algae is carefully brushed off each coral piece
  • Each coral table has 8 sections; each section has 20 – 25 coral fragments
  • These fragments are a mix of different species and genotypes, ensuring both species and genetic biodiversity
  • Depending on the species, the fragments take 25 – 40 weeks to grow into a transplantable coral colony
  • All findings and important indicators such as growth rate and coral genus diversity are recorded
  • To ensure biodiversity and genetic integrity, clusters of 4 – 5 pieces will be transplanted together onto different reef sections
Meet the team

The daily land-and-sea activities of Oceans Without Borders’ team of Community & Conservation (C & C) marine rangers, headed up by Project Manager, Nancy Iraba, are not only developing a growing body of invaluable research data, but also maintaining an active programme of environmental awareness.

Their duties include dedicated time tending the Mnemba Island coral nursery, which is core to the Coral Reef Restoration Project, conducting regular beach erosion surveys, and interactive community time, sharing environmental learnings with  school learners, young people, boat operators and fishermen.

Nancy Iraba

Dar es Salaam

For anyone choosing a marine sciences’ career in Zanzibar, there is the opportunity to shine; but you need to be ready to keep learning and evolve.

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Nancy is a self-proclaimed “science communicator” with a passion for sharing knowledge and working with coastal communities. She holds a degree in aquatic sciences and fisheries, together with an M.Sc. in marine sciences and is a qualified Dive Master. Her position as Oceans Without Borders’ Mnemba Island Project Officer requires a broad skill set as she plays a leading role in data collection, team management, guest interaction and community conservation lessons.

Iliyasa Haji Mdigo

Kigomani Community

A marine ranger is an exciting career option for young people interested in conservation, especially on Mnemba Island, as the Blue Economy develops.

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Following the completion of his schooling and three years of tertiary studies at Sumait University, Zanzibar, Iliyasa broadened his skills and work experience through a number of different avenues, including time as an entrepreneur, tour / water sports guide, and schoolteacher. The opportunity to be an Oceans Without Borders’ Community and Conservation (C & C) marine ranger opened up a whole new world of possibilities.

Hija Khamis Uledi

Mfurumatonga Community

Young people wanting to be marine rangers must have a love for marine environments, and ideally have some experience interacting with marine life.

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Hija was an active member of his high school’s environmental club and graduated with several awards including an Environmental Certificate. He went on to do a Intercultural Relations Diploma at Tumaini University, Dar es Salaam, before working as a young entrepreneur. His passion for the environment made him a strong candidate for the position of an Oceans Without Borders’ Community and Conservation (C & C) marine ranger.

Haji Mohammed Ali

Nungwi Community

Marine rangers have the chance to write the future. They’re environmental revolutionaries, “doctors” of the ocean, of the animals and communities.

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Haji has always had an interest in conservation. Following his completion of high school, he completed some short courses in computer science, management, and conservation before taking up a position as a receptionist in a small hotel. When he saw the Oceans Without Borders’ advertisement for a Community and Conservation (C & C) marine ranger, he was quick to apply and started his training following a successful interview.