Scooped up by the tonne
Purse seining
This is a relatively new technique, but now accounts for 60-80% of the total Mediterranean catch. Purse seines are enormous bag-like nets that are set around a tuna school then pulled closed from beneath. They are the only method that allows the mobile harvesting of live tuna - essential for the recent practice of fattening tuna in cages for the Japanese sushi and sashimi market.
A large fleet of spotter planes and helicopters is ready and waiting for the tuna as they enter the Mediterranean. Such aircraft are now routinely used to locate bluefin tuna schools by nearly every fleet targeting bluefin tuna in the Mediterranean.
Since 2001, the use of spotter aircraft has been illegal in the month of June, in an attempt to protect spawning tuna. However, illegal flights during this month have been observed inside Libyan airspace and operating from Malta and Lampedusa Island, Italy.Once a school has been located, the fishing vessels move in for the catch. Most are caught by high-tech, large-scale purse seine and longline fleets. A few smaller fisheries also operate, such as traditional trap fisheries. There are also illegal driftnet fisheries in some areas, like the Gulf of Lions.
The bulk of the purse seine catch takes place from May to mid-July, when the fishing season closes for one month. These fleets make huge catches: an incredible 25,000 tonnes of bluefin tuna - nearly 80% of the total quota for the entire Mediterranean and Eastern Atlantic - was caught in barely two months in 2004. Most of these catches are transferred to cages for fattening.
Alarmingly, bluefin tuna catches in the Mediterranean are now well above quota limits, primarily due to increased demand for farmed tuna. Fishers are also disregarding size limits and catching large numbers of juveniles as well. The fleets responsible for illegal fishing activities belong to Mediterranean countries.
Caught at sea
Even Atlantic bluefin tuna that make it out of the Mediterranean after the breeding season are not safe from fishing vessels. The species is targeted wherever it is abundant, including along northern African and European coasts, the East Atlantic, the West Atlantic, and along the North American coast. In the last decade, fisheries for bluefin tuna have also developed in the Central North Atlantic, where recent tagging studies have shown that tuna from both the western and eastern populations concentrate.
