The mouth is the best place to ID salmon species for those who are not sure. Check for prickly teeth that will cut you if you run your finger across them with a bit of pressure applied. They are primarily fish feeders, Will be Chinook or Coho. Now look at the flesh/gums where the teeth protrude from, black Chinook, white Coho. No sharp prickly teeth means they ate primarily plankton/shimp feeders, pink, sockeye and Chum. Pinks are easily picked out from these 3 as they have Oval spots on the tail and very small scales. They also will make your boat look like you just slaughtered a pig in your boat with all the blood splatter. Sockeye and Chum are the hardest to distinguish between especially if the Chum was caught early when still silver bright. If sockeye are closed to retention it is best for those who can’t tell the difference to just assume it a sockeye…. unless its over 15pounds.