Colombo, Sep 5: Sri Lanka has released 80 Indian fishermen who were arrested by the Sri Lankan Navy for allegedly fishing illegally in the island nation's territorial waters, according to a media report. Four of them were rescued by the Sri Lankan Navy when they were drowning in northern seas on August 31 while the others have been arrested for trespassing into the Sri Lankan territorial waters and engaging in illegal fishing activities, The Colombo Page reported. The 76 Indian fishermen were apprehended on separate occasions by the Sri Lankan Navy and Coast Guard for engaging in the illegal fishing method of bottom trawling in the Sri Lankan territorial waters. The repatriated Indian fishermen were handed over to the Indian Coast Guard Ship 'Sarang' at the International Maritime Boundary Line north of Kankasanthurai, the report said. Fishermen from both countries are arrested frequently by the maritime security agencies of both countries for illegal fishing and often stray into illegal waters due to absence of any proper technology to confirm the coastline border between Pakistan and India near Sir Creek in the Arabian Sea.