The fishermen — Sakthivel (54), Arunagiri (54), Sekar (66), and Balu (54) — were detained along with a mechanised boat owned by Sesoraja for allegedly crossing the maritime boundary.

They were taken to a naval camp in Kilinochchi, where an inquiry is under way.

According to sources, more than 200 mechanised boats with over 1,000 fishermen had ventured into the sea from Rameswaram a day earlier.

Fishermen said incidents of arrest, attacks, and damage to boats and nets by the Sri Lankan Navy continue to be reported frequently.

The fishing ban season began on Tuesday night.

The arrest has caused concern among fishermen and their families in Rameswaram.