The 40 Vietnamese crew on the so-called 'blue boats' remain in custody in Solomon Islands almost a month after they were arrested.
The crew and the boats were taken into custody last month after they were found diving for beche de mer in Rennell and Bellona.
Last week, the crew were fined about $US99 each, while the owners of the boats were fined $US4.6 million dollars.
The men are being held at the Rove Detention Centre in Honiara while the immigration department decides what to do next.
The Solomons' public broadcaster reported the men will have until next Monday to pay the fines.
It said if the owners failed to pay, their boats would be destroyed.