The patrols were co-ordinated by Border Protection Command and involved officers from Defence, Customs and the Australian Fisheries Management Authority (AFMA).

Five vessels were found fishing Australian waters north of Darwin near Evans Shoal. AFMA officers requested that the fresh trepang onboard be returned to the ocean.

The 57 crew were handed over to Customs in Darwin for processing and transferred to the Department of Immigration and Citizenship.

Another foreign fishing boat was spotted by a Customs Coastwatch aircraft east of Cape York. Australian Customs intercepted and boarded the shark boat approximately 60 nautical miles south of Thursday Island.

The crew was taken to Weipa before being transferred to Darwin for further investigation.

"The continued success of these operations is due to commitment of all agencies involved to protect the Australian Fishing Zone against illegal activity," Deputy ADF Commander Border Protection Command, Air Commodore Ian Meyn said.