Thirteen Vietnamese nationals are being detained in Cairns after their fishing vessel was apprehended in Australian waters.
Australian Border Force officials found more than three tonnes of sea cucumbers, considered a delicacy in Southeast Asia, on the vessel after intercepting it near Saumarez Reefs, northeast of Rockhampton.
The crew were observed dumping some of their catch overboard as the agents approached the boat on November 19, three days after it was first detected inside a conservation zone.
Diving equipment, including eight air-lines, was also found on board.
The crew was escorted to Cairns, where the men are being detained as the Australian Fisheries Management Authority considers whether to lay charges.
"Illegal fishing undermines the very rules and regulations we have in place to ensure the economic and environmental sustainability of Australia's fisheries," the AFMA's Peter Venslovas said.