SINGAPORE - Thousands of fish were found washed up on shore at Lim Chu Kang jetty on Saturday in the latest in a series of mass deaths.

Breeds big and small, including catfish and mullets, were discovered on the beach near where several fish farms are situated in the Strait of Johor.

Both sea and farm fish were affected.

Farmer Ong Kim Pit, 65, told The Sunday Times that he first saw fish jumping out of the water on Friday night, adding that his baby mullets were worst hit.

"It happened within minutes," he said. "My fish were jumping and jumping in the water. I don't know why."

Cleaners were seen removing bags of dead fish on Saturday.

It is not yet known what caused the mass deaths, but they came a week after a deadly wave of plankton bloom wiped out almost all of some Changi farmers' stocks.

The Agri-Food and Veterinary Authority (AVA) said the bloom had killed an estimated 500 to 600 tonnes of fish as of last Wednesday, and affected 55 out of 63 farms in the East Johor Strait.

The AVA's preliminary findings showed elevated levels of Karlodinium veneficum in seawater samples, which has been associated with fish deaths worldwide.

Meanwhile, photos of dead fish at Kranji Reservoir Park and Sungeh Buloh Wetland Reserve also surfaced online on Saturday.

kcarolyn@sph.com.sg