Half of the coral life around a stretch of reef off Pulau Hantu has died over an 18-month span, according to a new survey which conservationists cited as another reason for new laws to protect marine life.
Conducted by enthusiasts from a marine conservation group known as Blue Water Volunteers, the survey, done in October last year, found that hard coral cover off the Hantu site, at a depth of about 3m, was down to about 30 per cent of the area surveyed. [See data at the Coral Reefs of Singapore webpage].
When the same team had surveyed the same site in March 2003, the coral cover then was about 60 per cent.
See the 24 Oct 2004 report of the
Blue Water Volunteers Pulau Hantu dive
and the results at The Blue Tempeh.
Marine biologist Jani Thuaibah, 23, one of the two divers who conducted both surveys, said she was shocked at the extensive loss.
'Even if you take into account that observer errors may have crept in, given that these were volunteer surveys, the big loss of coral cover in that area is undeniable,' she told The Straits Times, adding that anyone who has been diving there regularly would have noticed it.
Experts estimate that Singapore has lost more than 65 per cent of its reefs since 1986.
A small island off Singapore's southern shores, Hantu is known to be rich in marine life. [See Pulau Hantu - A Celebration of Marine Life].
The latest volunteer surveys have been backed up by years of more detailed studies by the Department of Biological Sciences at the National University of Singapore, which have seen hard coral cover drop steadily.
Known as the rainforests of the ocean, corals are fertile spawning grounds for marine life. Like trees, they also absorb noxious carbon dioxide and prevent soil erosion from the shore.
But most importantly, of late, they have been regarded as treasure troves of immense medical potential - scientists suspect they could yield cures to many deadly diseases.
Under the guidance of Professor Chou Loke Ming, an internationally known marine expert, the department has been monitoring six reef sites on Singapore's southern shores through surveys roughly once every two years. The last survey was in 2003. According to Prof Chou, all six sites have seen an erosion of hard coral cover between 1988 and 2003, the most extensive - about 81 per cent - being at a site at Hantu West. Another site, off Pulau Semakau, had seen coral cover shrink by 62 per cent.
The biggest reason for the decline, says Prof Chou, is sedimentation. Blankets of silt churned out by land reclamation and regular dredging of shipping channels in the area are literally smothering the corals to death. Corals found in deeper areas have suffered the biggest casualties, with the silt blocking off both sunlight and food.
Despite the loss, over 200 species of hard corals can still be found in Singapore's waters. But these too may die soon, given the constant sedimentation problem, experts say.
Stopping reclamation or dredging activities, however, is not the only solution to saving Singapore's rich marine life, said Prof Chou.
Simple 'silt screens' - large fabric filters placed near areas under reclamation or where dredging is being done - have been known to be effective in blocking silt from reaching the corals or other marine creatures, said Prof Chou, whose team has also been trying to improve the condition of the reefs over the years, by trying to 'rehabilitate corals' - by helping them grow again - in little patches.
'But there is no point in such rehabilitation projects unless we tackle the root problem - sedimentation.' Careless shipping vessels were also known to damage reefs, he added.
Part of the problem, according to Nominated Member of Parliament Geh Min, is that while the Government has taken steps to protect Singapore's terrestrial biodiversity, not much has yet been done to protect our marine wealth.
She suggested that the National Parks Board, or a central coordinating body set up specially for the purpose of conserving our biodiversity, be informed well in advance of any new reclamation work.
'Then they could quickly arrange for surveys to check if we are in danger of losing any potentially valuable natural resource because of the development work,' she told The Straits Times.
When contacted, an NParks spokesman said the board was continuing to 'monitor' reefs, but hinted that preserving marine diversity was a task that it could not do alone as it did not have the 'jurisdiction' to manage all coral reefs.
'Corals continue to be under the purview of the Singapore Land Authority, and the Urban Redevelopment Authority oversees coastal development and land reclamation,' the spokesman said.
Speaking on the issue in Parliament on Jan 25, Dr Geh Min underscored the need for setting up a central coordinating body to look after Singapore's marine areas, which could one day yield millions of dollars in scientific and economic value.
'Right now, we often do not even know what we are losing,' she told The Straits Times.
What can you do about the situation? See the compilation at WildSingapore's newsletter, 4th February 2005.