Hundreds of fish, mostly smaller species, were found dead and floating in the Teesta river in the Jubilee Park area of Jalpaiguri town on Sunday.

Experts suspect the water was poisoned by unscrupulous fishermen to collect more fish as water level in the river has gone down. Officials of the fisheries department collected specimens and sent them for tests to ascertain the cause of the death.

In Jalpaiguri, there have been at least seven instances of dead fish floating in the past 10 years in the Teesta, Karala and Panga rivers.

On Sunday morning, residents of Saradapally in Jubilee Park saw hundreds of fish floating in the river. Many people collected the fish that were floating.

“We have information that many have collected the dead fish. We request them not to cook and eat them as there is a health hazard,” said an official of the Jalpaiguri district administration.

“Water levels have descended in the river. This might be one of the reasons for reduction in oxygen levels in the water, which led to the incident. We can confirm the cause only after we get lab reports,” said Suman Saha, an assistant director of the fisheries department.

The residents however, sounded unperturbed. Gobinda Biswas, a Saradapally resident, said: “I went there and saw fish floating. It seems someone put poison in the water upstream. Many of us have collected the fish.”

Raja Rauth, secretary of Jalpaiguri Science & Nature Club, said the administration should take stern steps to prevent unscrupulous practices like poisoning of fish.