The TESO meeting, headed by DMK president M Karunanidhi adopted a resolution in this regard, saying the islet was ceded by India to Sri Lanka despite the then DMK Government's opposition.
TESO pointed out that whenever a part of the country has to be ceded to another nation, it has to be done through a legislation after getting nod of both Houses of Parliament.
"As far as Katchatheevu is concerned, no such legislation was enacted. And it is true that ceding is not constitutionally valid since the islet was ceded to Sri Lanka by way of an agreement. Therefore, it has been decided to move the Supreme Court on behalf of TESO to cancel the 1974 agreement and declare Katchatheevu is part of India," the resolution said.
Chief Minister Jayalalithaa as opposition leader in 2008 had moved the Supreme Court against the agreement, with the revenue department impleading in the case after AIADMK came to power.
TESO said the 1974 agreement had allowed traditional fishing rights for fishermen of both countries and both India and Sri Lanka could not prevent fishermen of either nation from fishing in Katchatheevu.
However, contrary to the agreement Sri Lanka was preventing Tamil Nadu fishermen from fishing there besides damaging their fishing nets and arresting them, it said.
It said the agreement was signed despite the then DMK government's strong opposition which had sought minimum requirements like fishing rights and participation in a church function in the islet by Indian fishermen. But these provisions were removed during the Emergency, it said.
Holding that the Centre is duty bound to protect the fishermen, the resolution said almost 600 Indian fishermen had been killed so far by the Sri Lankan Navy.
The resolution said it is accepted the world over there cannot be a maritime boundary to prevent fishing rights.
It voiced concern over increased instances attacks on Indian fishermen by the Lankan Navy and said government in March had asked the Centre to initiate diplomatic steps to check it and urged for withdrawal of the 1974 agreement ceding Katchatheevu islet to the island nation.