Tuna aren’t hunted they are fished, as are lots of other versions of sea fauna. Fishing isn’t really analogous to per-historic hunting for the simple reason that commercial fishing requires a level of sophistication that simply didn’t exist back then.
Sustainable fishing absolutely Can, and Does exist in some areas of the world today. But not for all species, and not for all nations and of course under capitalism the rewards for cheating will always threaten sustainability.
But to your original point, tuna could be sustainably harvested, but enforcement is basically impossible.