Atlantic Bluefin Tuna: Once abundant in Atlantic waters, fishermen now aren't able to catch their quota
By SUSIE MAH, SUN MEDIA
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DECLINE
- Scientists warn stocks of the Atlantic bluefin tuna are dangerously close to collapse after a decade of overfishing, triggered by growing Asian demand for sushi.
- The international quota of Atlantic bluefin tuna catch is 29,500 metric tonnes, although about 50,000 tonnes were being caught annually.
TUNA FACTS
- Tunas migrate, travelling from the tropics to the Arctic
- Their lifespan is about 15 years, but they can live up to 30 years.
- They're able to swim at speeds of 40 km/h and dive to depths of 1 km.
- Atlantic bluefin tuna can grow up to 4 metres long and weigh up to 680 kilograms
- Particularly prized in Japan for sushi, a single fish can sell for $45,000.
- Longline fishing -- used to catch tuna and swordfish -- is a long piece of rope or nylon that lies in the water supporting baited hooks. They might exceed 100 km in length and carry 3,000 baited hooks suspended on 40 metre-long branch lines spaced 50 metres apart.
- When longlines are paid out from vessels, seabirds attack the baited hooks, get caught or entangled in gear, are drawn underwater and drown. Longlines have also been criticized for catching non-targeted fish.
TRACKING
- About 1,000 bluefin in North America have been fitted with satellite pop-up tags that can transmit data back to U.S. and Canadian scientists.
- The 34 cm-long tags are darted into the fish on either side of the dorsal midline.
- The tags pop free from the tuna at a programmed time, float to the surface and beam accumulated data via satellite back to the lab.
Source: Int'l Commission for the Conservation of Atlantic Tuna (ICCAT), Gov't. of Canada, Greenpeace, WWF
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