How Mnemba Islanders are restoring their coral reef

Looking out over the Indian Ocean from Mnemba Island, it’s hard to believe that just three years ago, the beautiful coral reef surrounding this part of Tanzania’s Zanzibar archipelago was dying.

Under threat from climate change, overfishing and other human activities, the islanders face the loss of their livelihoods and the risk of complete displacement.

Eager to save the colorful oval reef, which lies quite close to the coast and is about 7km (4.3 miles) long, the small island communities have undertaken a conservation project to restore some of the have lost.

The initiative also aims in other ways to protect the coral reef, which is known around the world for its beauty.

The water is so clear that the reef, which lies 10m (32ft) below the surface, appears to be within touching distance.

But a few years ago, locals started noticing how stressed the coral looked – partly because of climate change, causing warmer ocean temperatures.

Coral may look like a plant, but it is a type of animal – actually many small organisms called polyps. They grow very slowly and create a hard outer shell by extracting salt from seawater, which then combines together to form colonies.

Coral reefs are sometimes called the “rainforests of the sea” because they create ecosystems that support a diverse range of marine life.

But when the water gets a few degrees warmer than normal, it causes corals to chase away the brightly colored algae that live inside and provide nutrients. As the algae leave, the coral fades, bleaches and eventually dies.

Explosives used by fishermen have also killed coral, as have unchecked numbers of cruise ships and divers causing damage to the reef.

Juma Mshindan, a fish seller on Mnemba island, said something was clearly wrong: “There is a significant difference in fish supply in the past compared to today. In the past, there were a lot of fish.”

Sustainable tourism group &Beyond and nonprofit Africa Foundation began working with islanders in September 2021 to help address some of these issues.

Underwater nurseries are created using wire mesh tables where coral fragments are grown for replanting on the reef.

They are cared for and raised by local divers who have been trained as conservation rangers.

It takes about two or three months for a coral colony to form and then rangers bring them to the reef.

Results so far have been encouraging, with 80% of coverage restored on the so-called “house reef” surrounding the island.

“It looks like they grew on their own,” said conservation officer Hija Uledi.

“We restored the reef and you can’t tell the difference. Now they have fish around. The work was great and many species could be seen.”

Conservationists also created artificial reefs – steel and stone structures placed about 3 km from the island and where conservation rangers also planted new coral growing from nurseries.

These operations aim to help replenish marine life – benefiting fishermen, and they have also become a destination for snorkelers and divers.

Dr Camilla Floros, chief scientist of the Africa Foundation’s Oceans Without Borders programme, said the recovery plan was taking great care in using the right materials – learning from mistakes in past around the world.

“When artificial reefs were in their infancy, people were using the wrong materials like tires to try and create them, which was not the right approach,” she said.

Dr Floros credits the success of regeneration work around Mnemba Island to the support of the local community.

“Whenever we have a new initiative, we discuss it with them and get their buy-in,” she said.

Atuwa Omar is a local resident who participated in the restoration process. Before taking on the position of conservation ranger, the 24-year-old girl stayed at home to take care of her young child.

“Being a ranger in this project at Mnemba Island not only enables me to provide food for my family, but also supports my son’s education,” she said.

Although Ms. Omar admits it was not easy for her because she was the only woman working on the project.

She has had to face the conservative attitudes of some who don’t want women participating – but she says such challenges are worth it.

Conservation groups have worked closely with local authorities, and the waters around Mnemba have been designated a protected area by the government of Zanzibar, a semi-autonomous region of Tanzania, in 2022.

This means action can now be taken to limit the damage caused by tourists and fishermen.

Bakari Jaha, coordinator of the Zanzibar Africa Foundation, points to the number of tourists who have visited the reef.

“Initially, the area faced significant pressure from tourism, with 200 boats carrying at least 400 guests into an area of ​​just 200 square meters,” he said.

“To preserve the area, the government together with &Beyond and the Africa Foundation decided to limit the number of visitors to 80.”

Previously, visitors had to pay $3 (£2.40) – this cost has now increased to $25.

“This approach not only enhances environmental protection but also increases revenue,” Mr. Jaha said.

Fishing has also been suspended around the house reef while it is being restored.

“We have seen positive changes. Illegal activities, such as the use of explosives, have decreased and fishermen have become more knowledgeable about sustainable fishing methods,” said fisherman Mshenga Ally.

The Zanzibar government says it is encouraged by the success of the Mnemba restoration project and is looking to expand it to other threatened areas.

Dr Makame Omar Makame, Director of the Zanzibar Marine Department said: “The government has identified 14 areas with undamaged coral reefs and other areas with damaged corals and we are planning plan to preserve them”.

“We have placed buoys so people can be careful and understand that fishing is not allowed there.”

The pressure on Zanzibar’s coral reefs mirrors the threats facing reefs around the world. Those involved in the Mnemba project say that while they cannot stop warmer ocean currents, they hope their efforts will help other threatened areas.

“The relationship between the sea and coral is vital to ocean health. We have seen coral regenerate, even at significant depths,” Mr. Jaha said.

“We are allowing marine conditions to restore the reefs to their original state.”