Wildlife & Biodiversity

Ocean heat takes a toll on coral reefs and tourism in Africa

Coral reefs along the east coast of Africa have been badly hit due to ocean warming and acidification. This has hit tourism badly. Some efforts, however, are underway to revive them

 
By Akshit Sangomla
Last Updated: Wednesday 30 May 2018 | 10:19:02 AM
Coral reefs along the east coast of Africa and the islands of Zanzibar, Seychelles and Madagascar can provide jobs to thousands in diving and other allied industries
Coral reefs along the east coast of Africa and the islands of Zanzibar, Seychelles and Madagascar can provide jobs to thousands in diving and other allied industries Coral reefs along the east coast of Africa and the islands of Zanzibar, Seychelles and Madagascar can provide jobs to thousands in diving and other allied industries

The most extensive coral bleaching event from 2014 to 2017 affected reefs across the world, including the Great Barrier Reef in Australia where the damage was intense; and also those found along the east coast of Africa; where the intensity of destruction was slightly less. Talking to Down To Earth, David Obura, director of Kenya-based non-profit Coastal Oceans Research and Development–Indian Ocean (CORDIO), explains the extent of damage in Africa. “Seychelles was the worst hit country, followed by Madagascar, while parts of Mauritius, Kenya and Tanzania were badly impacted. Comoros showed only a slight impact,” he says.

Bleaching is a process where corals lose their vivid colour and turn white. This happens when the zooxanthellae algae, which is in a symbiotic relationship with corals and provide them with food, die due to ocean warming and acidification. If bleaching continues for an extended period of time, corals eventually die. Coral bleaching and mortality exacerbated by climate change are one of the biggest threats to oceanic biodiversity. Coral reefs, which are mostly found in shallow oceans along the coastline, provide the perfect place for marine life to thrive, especially colourful fish.

The first-ever recorded coral bleaching took place in 1998. That year the El Niño Southern Oscillation, which occurs every three to seven years in the Western Pacific Ocean, caused massive bleaching of corals along the east African coast. Due to this, almost 20 per cent of corals were lost in the region. The fallout of bleaching and coral death is an increase in the growth of fleshy macro algae in reefs. The algae do not allow corals to revive by taking up their space. The 1998 event increased such algae cover in the oceans by 2.5 times. “Due to the bleaching event, coral cover in the region declined by 20 per cent and fleshy algae cover increased by almost 35 per cent,” says Obura, who also chairs the International Union for Conservation of Nature’s Coral Specialist Group.

Tourism hit hard

So, how does bleaching of corals, also referred to as underwater rainforests because of their important role in supporting marine life and biodiversity, affect the African economy? African corals are a big tourist draw. Reefs along the east coast of Africa and the islands of Zanzibar, Seychelles and Madagascar provide jobs to thousands in diving and other allied industries. Amidst civil wars and ethnic violence, it is only the tourism sector that offers Africans a stable and viable economy.

Widespread coral bleaching has badly hit the African scuba diving industry. According to a World Bank estimate, losses amount to US $2.2 million in Zanzibar and $15.09 million in Mombasa till now. Even Seychelles has lost considerable coral reefs and the country’s profits from dive tourism have dipped. The reefs around Dar es Salaam, a major city in Tanzania, have recorded 6 per cent mortality since 1998, according to Leonard Chauka, a coral expert at the Tanzania-based non-profit, Western Indian Ocean Marine Science Organisation.

As dive tourism across Africa has declined considerably, these days organisers bank upon novices or amateur divers, who cannot readily differentiate between healthy and non-healthy coral reefs. But on the whole, the dive industry is not dealing with the issue of bleaching and taking measures to generate public awareness. They are more concerned with dwindling visitors than with climate change, the real culprit behind reduced tourist footfall. “They don’t want word to spread that their reefs are declining due to climate change. They fear tourists will go elsewhere, and so it is a bit of a head in the sand approach,” says Obura.

However, things have started looking bright. Concerned tourism organisers are taking an interest in coral restoration. For instance, the dive industry in Zanzibar has approached CORDIO to help them with training for monitoring coral bleaching and overall reef health. “We are trying to present forecasts during the high risk season for bleaching that will help the dive industry as well as others to prepare for such events. There is also more coverage and awareness about the issue in tourism magazines and global discussions. So, things are picking up,” Obura points out.

Healthy future?

Chauka is optimistic about coral reef recovery vital for the earth’s ecosystem. He says that Acropora, a coral species found near Dar es Salaam, was affected the most due to bleaching. But it is fast at recovery. “There are also mild bleaching events that cause no mortality. Such reefs take a few months to recover,” Chauka explains. In the midst of gloom and despair, there is good news for scuba divers. Experts say despite the extent of bleaching, coral mortality is not as extensive as it could have been. There is indication that corals have developed a certain amount of resistance to heat stress. This can help them recover in the future, if ocean pollution, over-fishing and dynamite fishing are kept under control.

But recovery is a matter of many years. Obura says it will take another 15-20 years for coral reefs to recover fully under natural conditions. Another cause of concern is that the time gap between bleaching events is decreasing, thus not allowing corals to recover. Some experts also say that the reefs may never come back to their original state.

Meanwhile, the tourism industry is doing everything it can to divert visitors’ attention from corals. For instance, in Tanzania, there is an effort to promote national parks like Serengeti and Ngorongoro. In Zanzibar, historical place like the Stone Town and the Jozani Forest Reserve are being promoted. Oceanic activities have been limited to dolphin viewing and kite surfing.

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Deep winter convection and phytoplankton dynamics in the NW Mediterranean Sea under present climate and future (horizon 2030) scenarios

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