Mediterranean fisheries

Atlantic bluefin tuna have been fished in the Mediterranean for centuries. Today the Mediterranean fishery is the largest of all Atlantic bluefin tuna fisheries.

According to Food and Agriculture Organization of the United Nations (FAO) figures, it accounts for around 73% of all reported catches.

Mediterranean fishery facts:

• One of the world’s oldest fisheries. Atlantic bluefin tuna have been an important part of Mediterranean culture for 12,000 years, and have been fished in the Mediterranean for at least 2,600 years. Homer described the fish in The Odyssey, written in 800BC, and Aristotle described their migration and spawning in 350 BC.

• Traditionally caught using traps. Giant adults were traditionally caught by traps in artisanal fisheries. This method can be very selective and sustainable. However, the advent of high-tech purse seines and long lines has now all but replaced the traps. A few still exist, but have seen their catches fall by as much as 80% in recent years.

• Now mainly caught using purse seines. Purse seine nets are currently responsible for 60-80% of the bluefin tuna catch in the Mediterranean. The fleets operate throughout the Mediterranean, but particularly in the Tyrrhenian Sea, Ligurian Sea, the Strait of Sicily, Aegean Sea, and the Sea of Marmara. The largest fleet is operated by France; other countries with purse seine fleets are Algeria, Croatia, Greece, Italy, Libya, Malta, Spain, Morocco, Tunisia, and Turkey.

• Most of the catch destined for fattening in cages. Today, the majority of the Mediterranean bluefin tuna catch is transferred live to tuna farms - cages in which the tuna are fattened primarily for the lucrative Japanese sushi and sashimi market. In 2004, around 22,500 tonnes of Atlantic bluefin tuna were transferred to Mediterranean tuna farms, representing nearly two-thirds of the entire annual quota for the Mediterranean and Eastern Atlantic.

• Rapid growth in tuna farming. The number of tuna farms has increased exponentially since 1996, when the first appeared, to over 40 today. Farms are currently found offshore in Spain, Italy, Malta, Croatia, Turkey, Cyprus, Tunisia, and Libya. This explains why most bluefin tuna in the Mediterranean are now caught using purse seines - this is the only fishing method that allows capture of live tuna that can be moved.

• Characterized by massive overfishing. WWF estimates that actual catches in 2004 were around 1.5 times higher than the annual quota. Illegal fishing is a huge problem, as is the capture of juveniles. Much of this overfishing is driven by tuna farming.