Baby’s a Tuna, and It’s Feeling Blue

Bluefin tuna are being hunted to extinction. They have already been reduced to a small fraction of the global numbers of a hundred ago. They may disappear from the Atlantic Ocean by 2012. The average weight of those caught has already been dropping. Other kinds of tuna and related fish are also being slaughtered, but the bluefish will be the first to go under.

Bluefin tuna are the genus Thunnus in the family Scombridae, with several species, among them Thunnus atlanticus (blackfin tuna), Thunnus orientalis (Pacific bluefin), and Thunnus thynnus (Northern bluefin).

The bluefin have a big problem: they taste very good. Tuna have been eaten for centuries. Indeed, the word “tuna” comes from ancient Greek. Canned tuna greatly increased the consumption, but what is finally terminating the bluefin is sushi. Four fifths of the bluefin tuna consumption is for sushi and sashimi. Sushi is seaweed-coated vinegar rice wrapped around a morsel of food such as raw fish, and sashimi is the raw fish by itself.

Bluefin tunas taste good because unlike most fish, they are homeothermic (warm blooded); they metabolize their temperature, like mammals and birds. With a higher body temperature than the surrounding cold water, tuna have a large ocean range. The warmth also enables tuna to swim fast (“tuna” in Greek means “to rush”), which enables them to catch more prey. So bluefin tuna grow up to a size of up to four meters. Continue reading