The bluefin tuna can live for 30 years, grow to three metres (10ft) in length and weigh as much as 700kg (1,500lb). A prime specimen can fetch as much as £52,000 in the Tokyo fish markets.

"In my lifetime we've bought this majestic species to the doorstep of ecological extinction in the western Atlantic Ocean," said Barbara Block of Stanford University in California. "Electronic tagging provides the best scientific information we've ever had to manage these tuna and we must, as an international community, start to act responsibly to ensure the future of this species."