Toro, as the Japanese call it, is the fatty underbelly of the bluefin tuna served as sushi ----a delicacy that became more common with the advent of cheap refrigeration in the 1960s. This is just one of the ways that humans consume one of the few warm-blooded fish.
Unfortunately, bluefin tuna has fallen victim to overfishing. The Atlantic population of the giant fish, which grows to an average of more than 360 kilograms, has fallen by 90 percent. Global population is less than half what it was in 1970.