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March 6, 2015
Issuing its first comments on the algal bloom since last Saturday, the authority said last year’s plankton bloom cost 53 farms about 500 tonnes of fish.
The AVA also said it would help the affected fish farmers - who operate off Pasir Ris in the East Johor Strait - to recover and restart their operations, and enhance their resilience to environmental challenges.
AVA’s media statement and replies to queries came after Minister of State for National Development Mohamad Maliki Osman visited two affected fish farms today. One of the farmers he visited, Mr Gary Chang, told TODAY via the phone that he managed to minimise his losses to just over a tonne - or 10 to 15 per cent of his fish - by moving half of his stocks to the farm of a good friend in Malaysia. He enveloped the remaining half in canvas bags and aerated the water in the bags, said Mr Chang, who rears grouper and sea bass.
Dr Maliki said farmers who suffered severe losses may not have taken measures early enough. “Plankton bloom occurrences are very difficult to prevent, but it is possible to reduce the impact. Whilst we provide assistance to help farmers tide over this difficult period, it is also important for farmers to do their part to take mitigating measures early,” he said. The AVA is looking to build up farmers’ resilience against these incidents, such as through robust contingency plans and contingency exercises. It will also ask farmers who have taken early action to share their experience with other farmers, Dr Maliki added.
Farmers reported the bulk of deaths to have occurred in the pre-dawn hours last Saturday, and many dead wild fish also washed up on Pasir Ris beach over the weekend. TODAY reported on Wednesday that a laboratory test had identified the algae species to belong to the Gymnodinium group, but AVA said its preliminary findings point to the Karlodinium veneficum species, which has been associated with fish kills worldwide.
According to website algaebase.org, the Karlodinium veneficum has been detected in places including France, Korea, Australia and New Zealand, and is known to produce karlotoxin, an agent responsible for fish kills. According to Western Australia’s Swan River Trust, there is no evidence that this species is toxic to humans.
The AVA said the dead fish had gill damage caused by plankton. No marine biotixins have been detected in fish samples from affected farms and live fish harvested from the farms are safe for consumption, it added.
DHI Water & Environment, which did the laboratory test for TODAY, said that the seawater sample tested was examined at a magnification of 400 times. At that level, species of algae belonging to the Karlodinium and Gymnodinium groups would appear very similar. To be able to positively identify the algae species, a genetic test or a microscope with 1,500 to 2,000 times’ magnification would be needed, said Dr Hans Eikaas, head of environmental technology and chemistry at DHI, a not-for-profit offering consultancy and water-modelling services.
To his knowledge, no Karlodinium algae has been found in the East Johor Strait, although they have been found in the West Johor Strait, said Dr Eikaas.
Blogger and marine enthusiast Ria Tan reported seeing dead wild and farmed fish at Sungei Buloh Wetland Reserve Extension, which is near the West Johor Strait, on Wednesday afternoon. But West Johor Strait farmer Malcolm Ong said there have been no fish deaths on his farm so far. His staff are on alert during this “dangerous period” and have pumps and aerators on standby, said Mr Ong, chief executive of Metropolitan Fishery Group, which is a major stakeholder in Singapore’s largest marine fish farm, off Lim Chu Kang.
On how it was dealing with plankton bloom in the longer term, the AVA said it has been working with the Tropical Marine Science Institute of the National University of Singapore on plankton bloom studies since last year’s episode. The studies, for the development of effective mitigating solutions, are ongoing, it said.
The AVA also called for proposals to design and develop a closed-containment aquaculture system for coastal fish farming last year. It recently awarded the tender to five companies, which will be working on a sustainable option for fish farms to minimise exposure to changes in the environment, such as plankton bloom, said the authority.