As they have gotten closer to Sri Lankan waters, or crossed into them, fishermen say, the Sri Lankan Navy is often waiting. One fisherman, a wiry, wet-eyed man named Pakkirisamy, pulled off his shirt to show bruises and welts on his back. He said Sri Lankan naval officers beat him last month with steel rods and heavy ropes. He said they dumped his fuel in the sea and ordered him to return to India. He rigged a sail and arrived eight hours later.

It is a common story. Other fishermen described their equipment being confiscated, their cellphones stolen and their iceboxes of fish seized. Several described being attacked by Sri Lankan sailors even as a bilateral agreement between the two countries prohibits such treatment. Once, they said, Sri Lankan naval ships only harassed the bigger trawlers, but now they were going after small boats, too.

“This is risky work,” said a fisherman named Dhanabal. “But we don’t have any other skills. We are illiterate. We are poor.”

The question of maritime boundaries is a touchy one in Tamil Nadu. In the 1970s, India and Sri Lanka agreed on a maritime boundary in which India ceded to Sri Lanka an island called Katchatheevu and bartered away the surrounding fishing rights. Today, many fishermen in Tamil Nadu, as well as the state’s elected leaders, want to reclaim the island and the fishing rights as part of what they consider their heritage.

During the Sri Lankan civil war, Indian fishing boats faced risks and, occasionally, live fire from Sri Lankan gunboats. More often, though, the Sri Lankan Navy was distracted by the war, allowing Indian boats to operate freely and with little competition, since Sri Lanka’s fishing fleet was often grounded by the conflict.

Image In Vellapallam, the dispute between India and Sri Lanka is deeply personal, because fishing is practically the only livelihood available. Credit... The New York Times

Now, though, Sri Lankan fishermen are returning to the sea and have complained of poaching and overfishing by Indians — especially the extensive Indian use of bottom trawlers and monofilament nylon nets, each banned in Sri Lanka. In February 2011, Sri Lankan fishermen formed a flotilla and captured 18 Indian trawlers and 112 fishermen before releasing the boats under government pressure.