200,000 fish in farms off Pasir Ris dead

Plankton bloom causes losses reaching hundreds of thousands of dollars
Carolyn Quek & Jessica Lim, Straits Times 1 Jan 10

MORE than 200,000 fish - almost the entire stocks of 13 fish farms here - have been wiped out by a plankton bloom in the waters off Pasir Ris Beach.

The problem started about 10 days ago and may get worse. The fish in farms further out at sea, near Pulau Ubin, are beginning to die as well.

Already, fish farmers who spoke to The Straits Times are describing their losses as the biggest in the 10 years they have been in business.

Six farmers say they have lost hundreds of thousands of dollars from these stocks, cultivated over the last two years; the tiger garoupas had been primed for harvest for next month's Chinese New Year.

The Agri-Food and Veterinary Authority (AVA) explained that plankton blooms occur when one species of these drifting marine organisms predominates over others and multiplies quickly.

The rapid increase in the number of these organisms drains the seawater of oxygen, which leads to fish and other animals suffocating.

The fish farmers say this is the first time their businesses have been hit in this way.

Mr James Low, 53, whose farm is about 3km off Pasir Ris Beach, said he knew something was amiss when his fish started surfacing and gasping for air.

Then they started dying in their netcages, which are nets suspended in the sea.

Alerted to the problem, the farmers banded together to come up with ideas to salvage the situation.

Air pumps were placed in the net cages to raise oxygen levels in the water.

The cages, which are usually pitched at a depth of about 3m, were also lowered further into the sea, and medicine was fed to the fish.

In a last-ditch attempt, some farmers released their fish into the sea to raise their chances of survival, but this did not seem to work either.

Earlier this week, The Straits Times reported that about 1,000 dead fish, mainly tiger garoupas, had washed ashore.

Fish farmer Phillip Lim, 47, whose farm is about 1km offshore, said: 'We were taking care of thousands of lives. Now they are gone, just like that.'

The AVA says its investigations show that the current plankton bloom was triggered by a combination of factors:

One is the fickle weather, which has shifted between bouts of sunshine and heavy rain.

Another is seawater becoming enriched by nutrients from the land, which were washed into the sea by the rain.

A third factor lies in the tides. Evidence has surfaced that little water exchange - and thus little flushing - occurs between high and low tides.

The farmers had thought at first that the plankton bloom was the result of the Serangoon Tidal Gates' regulation of the water levels for the upcoming Serangoon Reservoir near the fish farms.

But the Public Utilities Board has since clarified that the tidal gates have not begun operations.

The AVA said its officers were monitoring the water conditions off Pasir Ris, and that it had sent an advisory to all fish farms on measures to take to minimise the effects of the plankton bloom.

The farmers interviewed say they do not have enough capital to rebuild their stocks, and that even if they did, they do not know when it would be safe to start rearing fish again.

Said Mr Low: 'We hope the Government can help us with some of our losses and also tell us when it is safe for us to start refarming.'

The AVA estimates that the 13 affected farms supply 0.5per cent of the fish consumed here each year.

The marine aquaculture industry, comprising 106 licensed coastal floating netcage fish farms in all, occupies 85.5ha of coastal water.

It produced some 3,235 tonnes of fish valued at $11.40 million in 2008, accounting for 4 to 5per cent of the fish consumed here annually.

The target is to raise this to 15per cent or 15,000 tonnes annually.

Related articles
Dead fish on Pasir Ris beach Straits Times 29 Dec 09;

For more details see:
Why are there so many dead fish on Pasir Ris? from wild shores of singapore with a closer look at the dead fishes, also on wonderful creations and singapore nature.

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