Batticaloa Lagoon

Batticaloa Lagoon covers roughly 6,000 hectares and is separated from the Indian Ocean by a thin barrier island, making it one of the largest coastal lagoons in Sri Lanka. The lagoon is famous locally and in scientific literature for the 'singing fish' phenomenon: on calm nights around the full moon, a mysterious humming sound rises from the water, described variously as a low organ note, crickets, or distant bells. Scientists attribute the sound to the feeding or breeding behaviour of a species of catfish or mollusc, though the exact cause remains debated. Boat tours of the lagoon depart from the Kallady Bridge area, passing mangrove channels, bird roosts, and small fishing villages built on stilts. The Dutch colonial Batticaloa Fort, still in use as a government office, sits on the lagoon edge near the Kallady Bridge.