There is new evidence that large quantities of fish from west Africa are being "stolen" from communities heavily dependent on fishing, and loaded on to illegal vessels bound for South Korea.
Satellite technology suggests that a 4,000-tonne fishing vessel is currently transporting illegally caught fish from Sierra Leone to Busan, South Korea's second-largest city, feeding high demand for seafood in Asia.
The Environmental Justice Foundation (EJF), which uncovered the case, said it was part of the biggest trade in illegally caught fish in the world.
It detected the Korean-flagged vessel fishing close to Sierra Leone's Sherbro Island, where communities are heavily reliant on fishing for their food and income.
News of the vessel – believed to be transporting more than 4,000 boxes of illegally caught fish – comes amid growing concern about falling fish stocks in wst Africa, as more traditional fishing communities are pushed into poverty.
Last year the Guardian reported that some fishermen along the west African coast found their catch was down 75%, in a region already feeling the effect of overfishing from heavily subsidised EU vessels.
But there has also been increasing attention about the role of Korea, which is becoming notorious for its illegal fishing in the region. Three Korean-flagged vessels are currently under arrest in Liberia, following reports of illegal fishing from coastal communities in the country.
West Africa is believed to have the highest levels of illegally caught fish in the world, a trade which some estimate costs the global economy up to $23.5bn (£14.5bn) a year.
"Illegal fish is still getting to market," said Steve Trent, executive director of EJF. "The communities affected by these illegal operators are under grave threat, and so are the fish stocks they rely on for their daily protein and income.
"We are now calling on Korea to demonstrate their commitment to combat pirate fishing by … sanctioning the boats involved in this illegal activity. If they cannot do this, the EU should actively consider restricting trade from Korean-flagged vessels."
• This article was amended on 9 October 2013. The original version wrongly stated that the vessel transporting fish from Sierra Leone to Busan was 470 rather than 4,000 tonnes.