Restoring sharks and reef resilience in Mnemba Island Marine Conservation Area
Mnemba is one of Zanzibar’s most heavily used marine areas. The Mnemba Island Marine Conservation Area was declared in 1988, but for much of its history the area has lacked effective implementation, enforcement and science-based management. As a result, sustained fishing pressure and unregulated tourism led to widespread coral reef degradation and the near-complete loss of sharks and other large reef predators that once maintained ecosystem balance. Camilla is expanding the use of baited remote underwater video systems (BRUVs) to guide the establishment of fishery replenishment zones where ecological recovery will be encouraged by reducing fishing and tourism pressure in areas to increase fish abundance and improve reef condition.
Camilla Floros
My connection to the ocean began early in life, when I spent long periods in the Bazaruto Archipelago in Mozambique. I was captivated by the richness of coral reefs and marine life, but I also witnessed how increasing fishing pressure and tourism were changing these ecosystems. These experiences shaped both my love for the ocean and an early understanding that healthy marine ecosystems are inseparable from the people who depend on them. This path led me to study marine biology, with a focus on understanding threats to coral reefs, including coral bleaching, and examining how effective marine protected...
Restoring sharks and reef resilience through Fishery Replenishment Zones in Mnemba Island Marine Conservation Area
The key objective of this project is to support the establishment of fishery replenishment zones within the Mnemba Island Marine Conservation Area to restore ecological balance on coral reefs and create conditions for the recovery of sharks and other key reef species.
Sharks and other large reef predators have been almost completely lost from the Mnemba Island Marine Conservation Area due to decades of overfishing and weak management. Their absence has disrupted reef ecosystems, reducing resilience and fisheries productivity. Mnemba is also one of Zanzibar’s most heavily used marine areas, supporting intensive tourism and artisanal fishing. Fishery replenishment zones offer a proven solution, but only when grounded in credible science, led by government and supported by local communities – conditions this project is designed to deliver.
The Mnemba Island Marine Conservation Area (MIMCA) was declared in 1988 in recognition of its ecological and economic importance. However, for much of its history, the area has lacked effective implementation, enforcement and science-based management. As a result, sustained fishing pressure and unregulated tourism have led to the widespread degradation of coral reefs and the near-complete loss of sharks and other large reef predators that once played a critical role in maintaining ecosystem balance.
Despite these challenges, Mnemba’s reefs have shown remarkable signs of resilience. In recent years, small pilot protection zones established around the island have demonstrated encouraging ecological recovery. Reduced fishing and tourism pressure in these areas has resulted in increased fish abundance, higher numbers of juvenile fish and improvements in the condition of the reef. These early successes provide compelling evidence that reef ecosystems around Mnemba can recover when human pressures are effectively managed.
Oceans Without Borders has been working in the MIMCA under the guidance of the Zanzibar Ministry of Fisheries and Blue Economy to build the foundations for long-term marine management. Through a locally based team of community and conservation rangers, the programme has supported marine monitoring, community engagement and environmental education. This approach has strengthened relationships with government, fishers and tourism operators and has built local capacity for stewardship.
With this foundation in place, there is now a timely opportunity to scale up scientific monitoring and use robust ecological data to support the formal establishment of fishery replenishment zones. Doing so will help secure lasting protection for critical habitats and create the conditions needed for the recovery of sharks, healthier reefs and more sustainable fisheries.
This project will expand the use of baited remote underwater video systems to provide the scientific evidence needed to guide the establishment of fishery replenishment zones within the MIMCA.
The specific objectives are:
- To generate a robust baseline of fish and shark populations across reefs, sea-grass beds and deeper reef drop-offs.
- To identify priority areas for fishery replenishment zones based on ecological importance.
To support government-led planning and decision-making with regard to fishery replenishment zones with science-based recommendations. - To build long-term local capacity by training community and conservation rangers in marine monitoring.
- To create a clear pathway for the recovery of sharks, healthier reefs and more sustainable fisheries.