In a written reply, Defence Minister Manohar Parrikar said vessels and aircraft of Indian Coast Guard and Indian Navy are deployed on 24x7 basis for surveillance in the Indian maritime zones to protect national interests including for preventing infiltration and poaching by foreign fishing boats.
He said instances of illegal fishing in Indian waters by foreign fishermen come to the notice of government from time to time.
"A total of 233 foreign boats and 1686 foreign crew were apprehended by Indian Coast Guard during the period 2011-15," he said.