The South Korean Coast Guard on Monday caught two Chinese fishing boats engaging in illegal fishing in South Korea’s exclusive economic zone, or EEZ, near Incheon after intense resistance by the sailors.

The Coast Guard on Monday evening successfully chased the two vessels that were working while hiding the ships’ name with a fishing net in the South Korean EEZ, 100 kilometers southwest of Socheongdo, one of three westernmost islets adjacent to the North Korean coast near Incheon. Five boats catching fish nearby were expelled.

Eight sailors, including two captains aged 44 and 63, are being investigated for illegal fishing.

The fishers are being charged with catching 40 boxes of fish without South Korean authorities’ permission, the sea authority announced on its briefing on Tuesday afternoon.

The Chinese vessels had attempted to evade capture, sailing in zigzags for about 11 kilometers while being chased by a patrol boat of the West Sea Special Security Unit of the Coast Guard.

The 44-year-old captain reportedly resisted arrest, kicking South Korean Coast Guard officials and wielding a knife after they boarded his ship. The officials restrained the captain after firing tear gas.

The Coast Guard is considering applying additional charges against the captain with obstruction of official duties under the Criminal Act, which may result in a prison sentence of up to five years.