Fish decline prompts Wasini to help restore coral reefs

In the early 1990s, Thureya Mohamed would smile all the way to her house in Wasini island, Kwale county. She was always assured of enough fish for her family. Those days, the coral reefs were healthy.

Then things changed. Mass bleaching occurred in 1998, 2010 and 2016. This occurs when corals are stressed by changes in conditions such as temperature, light or nutrients. They expel the symbiotic algae living in their tissues, causing them to turn completely white.

Experts blame this on climate change and human activities, such as dumping of waste, mangrove cutting and sedimentation.

Healthy corals provide shelter for many species of tropical animals that rely on the structure provided by corals for their homes, and others find food that shelters in the crevices of stony corals. Coral degradation, therefore, has consequences for those like Thureya who rely on fishing.

Before the bleaching, corals along the coastal waters occurred in shades of olive green, brown, tan and pale yellow. The more they bleached, the more fish stocks dwindled.

Thureya, the treasurer of Wasini Beach Management Unit, said while poor fishing methods and gears also hurt supply, destruction of corals was the biggest problem. "We had to move in and reverse the trend," she said, referring to a community initiative in conjunction with the Coast Development Authority.

The mother of five said locals were concerned there would be mass die-off of coral reefs, spelling doom on the fishing sector. Scientists have already warned that the die-off could happen as soon as 2040.

One such scientist is Cody Clements, a Postdoctoral Fellow, Georgia Institute of Technology. Clements says coral reefs are home to so many species they often are called the rainforests of the seas.

"Today they face a daunting range of threats, including ocean warming and acidification, overfishing and pollution,” he said, adding that more than one-third of all coral species are at risk of extinction worldwide.

Clements is one of many scientists who are studying corals to find ways of helping them survive and recover.

BIGGEST THREAT

In October last year, an Intergovernmental Panel on Climate Change issued its special report on the impacts of global climate change on nature and society. 

The IPCC report specifically examined the results of warming of 1.5°C above pre-industrial levels. This is in the context of the global response to the threat of climate change, sustainable development and efforts to eradicate poverty. 

Of particular concern to the Wasini community after the report was released is the fact that Earth temperatures are still rising.

The IPCC report pointed out that the effects of climate change will not be disbursed uniformly across the globe. The rising temperatures will have a disproportionate impact, hitting the poor hard.

The report said damage to coral reefs has implications for several key regional services. It said coral reefs account for 10 to 12 per cent of the fish caught in tropical countries, and 20 to 25 per cent of the fish caught by developing nations.

This role is threatened by future sea-level rise, the decrease in coral cover, reduced rates of calcification, and higher rates of dissolution and bioerosion due to ocean warming and acidification.

The IPCC’s special report was an urgent wake-up call for action. As a recent report from the National Academies of Science, Engineering and Medicine shows, researchers are exploring many different strategies.

Some, such as managed breeding to make corals more tolerant of stresses, are already being developed at a small scale. Others, such as moving corals to colonise new areas, have not been tested yet.

Clements says many of the strategies in the National Academies report involve using biodiversity, both at the genetic and species level, to enhance coral reef resilience.

Examples include cross-breeding corals between populations, altering coral genes to give them new functions, such as higher heat tolerance, and moving stress-tolerant corals or coral genes to new locations.

"Promising advances in technology, such as mapping coral reefs from the air, may also help researchers assess coral health and determine which species they contain. This baseline information may help better inform management and restoration efforts," Clements says.

"Corals are in trouble, but they aren’t down for the count yet. Perhaps harnessing the power of their remaining biodiversity can help give them a fighting chance."

CORAL RESTORATION

Coast Development Authority (CDA) research manager Mwanasiti Bendera says all the efforts to rehabilitate coral reefs are being done together with a component of mangrove planting. 

"We are targeting to rehabilitate about 100 hectares," she said, adding that knowledge on the need to protect mangroves has increased.

"Apart from climate change, corals are also affected by human activities. These activities include dumping of waste, mangrove cutting and sedimentation."

There are four main steps in coral restoration. Firstly, awareness is raised among community members.

They are taught the importance of corals, the threats as well as causes, prevention and mitigation measures. These are done through the awareness forums.

Participatory mapping is carried out to incorporate local stakeholder participation. Coral reefs are identified before spatial information is developed. This includes their health status and threats affecting them.

In the second step, Bendera said, a diverse group of coral species with different growth forms is collected. This is done to maintain high diversity and prevent inbreeding. Coral fragments collected from donor sites are used for nursery establishment.

Corals growing on nursery conditions tend to grow three to five times faster than their natural counterparts and will survive in an extended range of physical conditions. Two nursery methods have been used successfully in Kenya: coral tree and nursery bed.

In the third step, corals are transplanted using cheap and simple methods. This is after two to three months. They are securely fixed on bare substrate of the degraded reefs or onto artificial reefs.

During the fourth step, coral reefs are monitored and maintained, as regular checks and maintenance are required. Measuring growth, survival and health of corals is done monthly.

Bendera said during the monthly monitoring, survival of out planted corals is scored and their general health status, such as disease or bleaching, is recorded.

An underwater camera is used to take photographs at regular intervals to track their growth, she said.

Soft brushes are used to clean and remove all algae and other organisms around the coral base.

The rehabilitation process is part of Climate Change Adaptation. 

CDA MD Mohamed Hassan said the project is under the Kenya Climate Change Adaptation programme through the Adaptation Fund.

Hassan said the three-year project tries to innovate blue economy and assist the community to harness marine resources.

"We are doing this with community members from Wasini. So far, we are engaging close to 2,500 members of the community," he said, adding that the move will improve fish population.

The MD said the programme has a fund of Sh150 million, but Sh50 million has been used so far.

CDA board chairman Kazungu Kambi said the boats they have do not go up to 200 nautical miles, but instead five.

Edited by Tom Jalio