Illegal fishing is a large but unevenly distributed global trade, with industrial fleets responsible for most of the estimated illicit marine wild-fish seafood by volume. The article estimates that the trade involves 8.4 to 15.4 million metric tons of seafood each year, worth $6.2 billion to $12.2 billion.

It also describes how illegal catch can be moved through ship-to-ship transfers, weakly regulated ports and false documents. Better detection using remote sensing and AI may help, but the article argues that enforcement will require transparency, international cooperation and policies that also address the needs of small-scale fishers.