Ahi, albacore, and plain old tuna

So far, I know of three different kinds of tuna - the regular grey flaky stuff you get in a can, the more expensive white, flaky stuff you get in a can, and the sublimely delicious and expensive pink stuff you order in restaurants.

Are they all from the same kind of tuna - say the difference between ground round and tenderloin. Or are they three different kinds of tuna?

“Ahi” (Thunnus albacares) is simply yellowfin tuna (or specifically yellowfin caught around Hawaii, but all of the yellowfin are pretty much the same, save for possible sub-species). The light tuna you see is Albacore, Thunnus alalunga and is the most prized. The other type is Blue Fin, Thunnus thynnus. Skipjack is another tuna, although not in the same genus: Katsuwonus pelamis.

As well as there being several species of tuna, there are also several types or grades of canning (at least there are here);
tuna flakes - very finely broken pieces of tuna, in oil or brine - the meat-to-liquid ratio for this stuff is often very poor.
Tuna ‘steak’ - the can contains a single steak-cut piece of tuna that fits exactly in the can
Tuna chunks - sort of halfway between flakes and steak - dice sized pieces of tuna

Obviously the stuff that’s going into the cans as ‘steak’ can only come from certain parts of the fish; chunks and flakes are less critical.

Yep. Could be a leg or a wing.

I’m a breast man myself.

More likely a nugget.

Which part of the tuna is the nugget?

The elbow.

That’s what I’ve always wondered about chickens.