The backwaters in Dhanushkodi witnessed mass fish deaths on Saturday, owing to a depletion of the oxygen level in the shallow waters. The incident was similar to to the one that occurred recently on the seashore in the Gulf of Mannar, where fish died due to the sudden blooming of micro-algae.
About three tonnes of fish were found dead at the backwaters in the lagoons adjacent to the Kothandaramar temple in Dhanushkodi, triggering panic among the fisher folk in the area.
Scientists from Mandapam Regional Centre of Central Marine Fisheries Research Institute (CMFRI) and officials from the Fisheries Department examined the dead fish and identified them as ‘Koimeen’.
R. Jayakumar, scientist in-charge, CMFRI, said the fish entered the lagoons en masse. The fish might have died of suffocation due to oxygen depletion when there was a rise in water temperature and in the absence of water current, he said.
The fish could have entered the lagoon when there was high tide and got trapped inside, he said. “Multiple factors such as rise in temperature, low depth of water, low tide and absence of water current resulting in low level of dissolved oxygen might have caused the deaths,” he said.
It was a low value fish and fishermen could dry them for poultry feed. Water samples and dead fish were collected for further examination, he said.