The Australian authorities say they have intercepted more than 20 foreign boats in the country's largest-ever operation against illegal fishing.
Australia suspects large-scale criminal fishing off its coast
The vessels, and about 200 crew, were stopped in a nine-day operation off northern Australia, Fisheries Minister Ian Macdonald said on Wednesday.
The move uncovered large-scale illegal fishing operating from Indonesia, he told Australian radio.
But he added that the "masterminds" may be based in other Asian countries.
"Investigations are continuing, but there is some evidence that this is organised, transnational criminal activity," Mr Macdonald said.
Australia has for years tried to stop boats from Indonesian fishing villages from poaching valuable trocha shells and sharks.
But some of the vessels intercepted in recent days were outfitted with sophisticated navigation, radar and communications equipment, Mr Macdonald said.
The detained fishermen are due to appear in court next week, Reuters news agency reported.