Evidence is emerging of unregulated and probably illegal tuna fishing in Libyan waters during this year’s conflict.
Signals recorded from boats’ electronic “black boxes” show a large presence inside Libyan waters, a major spawning ground for the endangered bluefin tuna.
Several strands of evidence, including a letter from a former industry source, suggest the involvement of EU boats.
The issue will be aired this week at the annual meeting of Iccat, which regulates tuna fishing in the region.
The European Commission believes any fishing in Libyan waters this year could be judged illegal.
EU Fisheries Commissioner Maria Damanaki told BBC News that she is also investigating whether Italian authorities made bilateral deals with Libya on tuna-fishing, which would contravene EU regulations.
The annual meeting of Iccat – the International Commission for the Conservation of Atlantic Tunas – opens in Istanbul on Friday, preceded by two days of talks within its Compliance Committee, which will begin to assess whether rules have been broken.
After the Libyan civil conflict began in February, Ms Damanaki’s office was set to request a suspension of all tuna fishing in Libyan waters, given that the breakdown in governance made regulation difficult.
On 7 April, Libyan authorities, in one of a series of letters obtained by BBC News, told Iccat that because of the “recent and exceptional circumstances” it was going to suspend all tuna fishing in its waters voluntarily.
Three weeks later, Libya sent another letter to Iccat cancelling the suspension, without citing its reasons.
Iccat chairman Fabio Hazin asked Libya to reconsider. It was too late to procure international observers for the vessels, as regulations require, he said; and Iccat members did not have the time needed to discuss and approve Libya’s proposed fishing plan.
In response to further correspondence, Dr Hazin and Compliance Committee chairman Christopher Rogers told Libyan official Nuredin Esarbout that “fishing by the Libyan fleet… in 2011 might be in contravention” of Iccat rules.
Ms Damanaki further warned that any catches would be “well on track to be deemed illegal”.
She asked EU member states to “monitor the activities of your national operators” to make sure they were not catching or trading potentially illegal fish.
She also warned that she stood ready to use recently adopted EU rules on illegal fishing against anyone involved in such activities.
Under Iccat rules, all purse seine boats – the type most common in bluefin operations – have to be equipped with a Vessel Monitoring System (VMS), an electronic gadget that transmits information including the boat’s location every six hours.
The statistical report prepared for the forthcoming meeting – also obtained by BBC News – includes a map showing the number of VMS signals received from various locations in the Mediterranean during the 2011 fishing season.
The biggest bursts of activity are in the spawning grounds where bluefin gather in the early summer; and this includes the waters off the Libyan coast.
This map does not show which vessels were operating there, although Iccat is believed to have this information.
According to environmental groups that monitor tuna-fishing ports, vessels authorised to fish in Libyan waters did not do so, remaining in French and Maltese ports all season.
If that is correct, it implies that boats from other Iccat member states were operating there, which would be illegal.
As well as the area extending 12 nautical miles off the coast which is the Mediterranean standard for territorial waters, Libya claims the whole of the Gulf of Sirte covering 57,000 sq km (22,000 sq miles) and a further “exclusive fishing zone” extending 62 nautical miles into the Med.