BRUSSELS, Belgium - An international scientific study says well over twice as much of the rare eastern Atlantic bluefin tuna is traded than catch quotas allow for, further threatening the survival of the dinnertime favourite at sushi bars across the globe.

The Pew Environment Group said Tuesday that the 141 per cent gap between the two last year does not even take into account the black market, which would further highlight the pressure the stocks of one of the world's most expensive fish are under in the Mediterranean and eastern Atlantic.

Pew bluefin tuna expert Lee Crockett that "the bluefin trade is rife with fraud and misinformation," and called for a change from a corruption-prone paper trail of documents to full electronic boat-to-chopsticks surveillance of the trade by the time the 2012 season opens.