[Beagle8U]

“Once they get chubby the salmon eggs and milt are eaten first, often not bothering with the carcass which the seagulls and crows appreciate.”

I thought the eggs and the skin was the most favored part. The skin is where the fat is.

[dainbramaged]

You're right about fat in the skin, depending on the species with King being the fattiest - then Sockeye, Coho, Pink and Chum in that order.
I've watched Brown Bears hold a 30 pound King down with their paw and peel the skin right off in two swipes, eat the eggs or milt (sperm) then the belly fat and walk away to the next fish.
They start getting selective with the type of food once they are up to weight.
The belly fat was my favorite part to put in the smoker, so good still warm - puts lead in your pencil, too.