All canned products are cooked.

The canning process, whether you do it at home in a boiling water bath or whether it is done in a in a commercial retort (a huge pressure cooker), always cooks the food. That's why you must be careful to follow the required processing time and temperature rules, and commercial canners follow the required processing time and pressure and temperature schedules designed by processing experts, to make sure the product is commercially sterile.

Tuna is cooked twice – the first time only enough to firm it up so that it can be boned and skinned efficiently; the second time in the canning process. Most canned salmon, which is packaged with the skin and bones, is only cooked in the can. If you buy fancier grades of canned salmon, packed without skin and bones, it goes through the same two-step cooking process as tuna.

Your question is not the least bit stupid. You only missed the mark in trying to differentiate between seafood and every canned food on earth.