Sixteen Tamil Nadu fishermen were arrested by Sri Lankan naval personnel when they were fishing near Katchatheevu, the fourth such incident this week, a Fisheries Department official said today. With this, the number of fishermen arrested for allegedly fishing in Lankan territorial waters have gone up to 44 since July 3. Fisheries Department Assistant Director K D Gopinath said the Lankan Navy surrounded the fishermen, who put to sea from here and snapped 50 fishing nets of some boats last night. The arrested fishermen and their three boats were taken to Kangesanthurai. They also hurled stones forcing other fishermen to retreat. Rameswaram fishermen's association president, P Sesuraja said about 580 fishing boats had ventured into the sea yesterday but the catch was poor due to the attack by the Lankan personnel. Chief Minister Jayalalithaa had writted to Prime Minister Narendra Modi yesterday, requesting him to take steps to secure the release of 80 Indian fishermen and 101 boats seized by the Lankan Navy. She had also said the root cause of the frequent arrests of the fishermen was the "unconstitutional" ceding of Katchatheevu to the Island Nation. On July 5, 17 fishermen from Nagapattinam were arrested for allegedly fishing in Lankan territorial waters, while six fishermen from Pamban in Ramanathapuram district were arrested the previous day. Five fishermen were arrested on Sunday.