Bluefin tuna are being caught faster than they can reproduce, which is terrible news for bluefin tuna and people who like to eat them (but seriously for the tuna). These fish are awesome, and I didn't know farming tuna was possible, but it is, with a few caveats. Bluefin in captivity don't procreate unless they're shot with a hormone-tipped spear gun (really). Also, the fish the bluefin are fed still have to come from somewhere, so calling farm raised fish sustainable is something of a misnomer. More sustainable though. I loved this video from Perennial Plate looking at a Japanese tuna farmer. The farmer seems so happy (but does not consider himself a conservationist).
You also ought to spend some time looking at the Perennial Plate back catalog of videos. Lots of gems in there. (via The Atlantic)