Five facts about threatened bluefin tuna

Scientists and campaigners warn stocks of the Atlantic bluefin tuna are dangerously close to collapse after a decade of overfishing, triggered by growing Asian demand for sushi.

Here are five facts about the Atlantic bluefin tuna:

* Despite weighing up to half a tonne, the bluefin (Thunnus thynnus) can swim in excess of 70 km (43 miles) an hour thanks to its stiff, aerodynamic body and warm-blooded circulation, making it one of the Mediterranean's top predators.

* The Phoenecians 3,000 years ago were the first Mediterranean civilisation to catch spawning bluefin with fixed nets; Roman armies fed their troops on dried tuna and Rome minted coins depicting the fish. Spain and Morocco still fish with fixed nets, known as Almadrabas, a word of Arabic origin meaning 'splashing place'.

* The bluefin's deep red flesh is prized among sashimi (raw fish) eaters in Japan, where around 80 percent of the Mediterranean catch is exported. One 200 kg (440 lb) Pacific bluefin sold for a record $174,000 at Tokyo's Tsukiji fish market in 2001.

* Bluefin typically mature at about three years old, making any recovery of the stock particularly difficult.

* There are two distinct populations of bluefin: one in the eastern Atlantic and Mediterranean, the other near the United States, though this is about a tenth of the size of the eastern group. Both are classified as overfished.