'Ranching' tuna the eco-friendly way - CNN.com

STORY HIGHLIGHTS Bluefin tuna farm off coast of Japan rears fish from hatchlings to fully grown-Beloved by sushi aficionados, wild bluefin tuna have become endangered-"Closed system" of the tuna farm in Kushimoto, Japan, could be sustainable solution-Farming does rely on large quantities of mackerel to feed tuna, critics say.

via edition.cnn.com

A neat story on efforts in Japan to farm raise bluefin tuna without capturing juveniles in the wild. Of course, it's not good enough for Greenpeace.