I grabbed these two beasts from the free fish bin yesterday. The one on the left is definitely a chum (dog) salmon and I think the one on the right is a sockeye (red), but it may be a coho (silver). Or maybe even a really small chinook (king), but I doubt it. I'm not an expert at salmon identification yet, but I'm getting better. Below is a close up of the chum salmon, also called a dog salmon.
In all of the online info I found about dog salmon, it says that they are nicknamed dog salmon because of their sharp canine-like teeth. It's hard to tell where the origins came from, but around here they're called dog salmon because these fish dont taste quite as good as the rest and are commonly throw to the dogs for dog food. Ugly little monsters, arent they?