Yes, and also because of osmosis. As you noticed, the salt creates brine. How it does this is by the salt infiltrating the salmon flesh, which, to stay in equilibrium, lets water molecules flow out of it into the surrounding pan. But once a liquid envelopes the fish, it 'entices' the salt to migrate out of the fish and into the liquid again, making the liquid salty. But equilibrium forces some of the now salted water back into the fish again - and that back and forth goes on all the while the fish is in the liquid.

In a way, although the 'heat' (migrating molecule-created energy) is extremely low, heat of a kind is generated, and that is in part why the salmon gets 'cooked' by it. Exactly the same thing happens with Ceviche and the acid (lemon) you create it with. You can overcook Ceviche, too!

If your salmon has been previously frozen, then 24 hours in the brine is sufficient to cure it, believe me. Try it, and let us know how it comes out.

Lisa