Rusty, I raised tropical fish for 19 years and I agree with you. That LOOKS like a "PLECO" (that's what we called 'em for short) You normally see then "suckered" to the side of the aquarium and your typical view of them is from their belly ie the first pic.
I just have a couple of questions, How big was it, there is nothing else in the picture for scale. I have had them gro to 8 or 9 inches long in some of my larger tanks, although that is uncommon. ALso, I am not aware of a saltwater variety of this critter. I guess I'm revealin' my ignorance here but is Calaveras fresh or salt water.
Just thought of one more thing. You say you caught it trolling, did you foul-hook it or did it actually bite your hook. Plecos eat algae and I've seen 'em graze on dead fish in the bottom of the tank but I can't see them getting after a moving bait.