The man, who had put out to sea with two others yesterday from Pushpavanam coastal hamlet, died after Sri Lankan Naval personnel tied a rope around his neck and pushed him into the water, fisheries department official sources said.
They said the Naval patrol boat intercepted the vessel and its personnel ordered all the fishermen to jump into the sea. While two did as they were told, the third could not do so as he had a hand injury following which they threw a rope around his neck and pushed him out, they said.
The two injured fishermen, who returned this morning with the body, have been admitted to a hospital.
Top police officials have rushed to the village to take stock of the situation.
Fishermen of the village did not venture into the sea today in protest against the continuing attacks.
This is the second such incident this month. On January 12, a Tamil Nadu fisherman was killed after Sri Lankan Navy allegedly opened fire in mid-sea.