Tuna is one of the mainstays of the world's sushi bars, and bluefin tuna is considered the top of the line. Or net, as the case may be. Japan consumes over half of the world's bluefin tuna, but with its popularity growing globally, the bluefin is becoming overfished and its numbers dwindling. So that's why an auction last Wednesday in Japan for a hefty fish brought a whopper of a bid: $400,000, as detailed in this article from Reuters. Missing from the article is outrage for the overfishing and practices that claim the fish while still young -- and before they can reproduce. But that might come once the prices top half a million dollars for a single fish. Bluefin tuna is usually called hon maguro or toro on sushi menus.