Mr Weekes believes Gilbert spent a few days feeding off Dorset to build up enough energy to swim out to the Atlantic Ocean and down to the Bay of Biscay.
"A 40ft container of products fell from the deck in a storm in the Bay of Biscay bound for the Spanish Christmas market last month, " she told the BBC News website.
Worse, latest data show that 36% of bluefin--which can grow to 1, 500 pounds--caught in the Mediterranean Sea and the Bay of Biscay fell beneath the 7-pound minimum set by ICCAT in 1998.
Combined with the funnelling affect of the Bay of Biscay trapping litter and debris in the north Atlantic, this means the beaches are routinely closed due to dangerous levels of bacterial pollution.
In 2005, the anchovy fishing grounds in the Bay of Biscay were closed due to concerns over depleting stocks, and the new catch allowances are being seen as a way of ensuring a sustainable fishing industry.