The girth, lots of it. This fish has spent some time behind his fair share of baitfish. A typical steelhead from the area looks less like a fat trout and more like an arrow.
Net marks. Note the line down his side forward of the dorsal. How much time he spent cooped up with whitefish and herring that came to a quicker end is one of those questions I'll have to ask the guy that probably released him. A lamprey scar adorns his port side as well. This fella has seen as much action on the front lines and in the brothels and any fish could hope to. He also decided to climb a bit further into the river than most fish in thirty-four degree water and give a good pound to the green eggs and ham seen in his mouth.
Regardless of water type, sex, species, barometric pressure, moon phase, month of year, bait, fly, presentation, spawning phase, latitude, Dr Juice, Sure Strike, day of week, time of day and all of that excellent et cetera, steelhead here typically do not give a good pound to anything. And especially in thirty four degree water. Also note the lack of chrome. With his river being open for only two weeks and the anchor ice cleared for less than that, this is the fish I go for when it's real, real early and I know I don't have a chance.