Mass fish death has occurred again in the backwaters of Aatrankarai, a fishing hamlet located on Vaigai river mouth near here on Thursday and Friday. Three weeks after mass fish death took place in the backwaters on August 8, hundreds and thousands of fish of various species were found dead, triggering scare among viaagers who eked out a living by fishing in the waters. Fisheries department officials, who inspected the backwaters, said the fish could have died due to depletion of oxygen level in the stagnant backwaters. The water remained stagnant for several months after the mouth bar got closed due to accumulation of sand mounds. When oxygen depleted and heat increased, physico-chemical parameters began to fluctuate, making it difficult for the fish and other species to survive in the water, officials said. Deputy Director of Fisheries P. Isaac Jayakumar and other officials from the fisheries inspected the backwaters. As suggested by them, villagers with manpower provided by the local panchayat collected the decayed fish and buried them in the shore. Letting in fresh seawater into the backwater would help increase oxygen level and this could happen only when there were high tidal waves, they said. After mass fish death took place on August 8, Collector S. Natarajan deputed Revenue Divisional Officer Baby who inspected and presented a report to the district administration. Villagers initially blamed the nearby shrimp farms for letting out chemical effluents into the backwaters, thus causing the death. However, the deaths on Thursday and Friday have taken place when the farms were dry. S. Mohamed Ali Jinnah, president of Aatrankarai Fishermen Cooperative Society, appealed to the district administration to initiate immediate remedial measures. For permanent solution, the government should construct groynes at the mouth bar, he said. While a small section of fishermen fished in the backwaters, most of the fishermen ventured into the sea for fishing and after the mouth bar got closed, they found it difficult to venture into the sea and keep the boats on the seashore, he said.