Bluefin tuna, unable to swim inside the lines, at risk of extinction

Apparently western Atlantic bluefin tuna don’t understand the concept of fisheries quotas, and may soon face extinction because of it, marine scientists report in the journal Nature. Bluefin tuna can grow up to 10 feet in length and weigh 1,500 lbs., and, due to high demand for sushi, they can fetch as much as $98,000 on the Tokyo fish market. Scientists have known there are two populations of bluefin tuna — a western population whose numbers have declined by 80 percent in the last 30 years and an eastern population thought to be larger — but weren’t sure if the different enforced catch quotas on these populations were really working. Electronic tagging of hundreds of tuna allowed marine biologists such as Stanford’s Barbara Block to see that using separate quotas for the two populations may not be effective, what with the fish seeing no boundaries and often voyaging into each others’ territories.