The true cost of dodgy fishing in Pacific tuna fisheries - potentially stretching over $600 million - has been condemned as "larceny on the high seas".
The figure has been revealed in a new 100-page report, prepared by marine consultant company MRAG Asia Pacific for a Pacific economic forum.
It is the first ever attempt to quantify the volume and value of illegal, unreported and unregulated (IUU) fishing in Pacific tuna fisheries.
IUU is a broad definition that covers vessels fishing in state jurisdictions without permission, misreporting or not reporting harvest volumes, or flouting conservation and management measures put in place for certain areas.
Using estimated volumes looking at the period between 2010 and 2015, and built on the best information available, the report suggested that IUU fishing was stripping around 306,000 tonnes of tuna from the fisheries - or somewhere between 276,000 and 338,000 tonnes.
This equated to value of around $616 million, or somewhere between $517 million and $740 million.
The report further found the volume of IUU product was highest in the purse seine fishery - accounting for around three quarters of it - while the tropical longline and southern longline fisheries accounted for around 19 per cent and 11 per cent respectively.
Amongst the main targeted tuna species, skipjack accounted for the largest proportion - about 33 per cent of total IUU volumes, and more than 100,000 tonnes worth.
Yellowfin made up the next highest volume - about 31 per cent of it and 96,126 tonnes worth, or an equivalent 15 per cent of the total yellowfin catch in the Western and Central Pacific Fisheries Convention Area in 2014.
Although the report was described by its authors as a "first cut", the estimates were still lower than the commonly quoted $700 million to $1.5 billion ballpark estimate for IUU fishing in the western and central Pacific.
It also found that the estimates were dominated by licensed fleet vessels, and that relatively high levels of IUU fishing in coastal states on the western Pacific seaboard influenced the overall results.
The authors suggested a range of ways to tackle the problem, such as stronger monitoring through the supply chain, electronic technology and observers on board vessels.
"The reality is that, for Pacific Island nations, this is their exclusive economic resource," said Shane Jones, New Zealand's Ambassador for Pacific Economic Development.
"Every dollar pilched from fishing is a dollar denied to our Pacific neighbours."
However, he said, the situation was considerably worse in the Indian Ocean.
"The major challenge for New Zealand and our Pacific neighbours in the larceny that is happening on the high seas."