I don't think I measured the right spot for girth (tried just ahead of the dorsal). Looking back over the photos, I figured the thickest spot to be further up the body, but I don't know how to estimate how much more girth that would translate to. Looked at a number of pics of Rainbows around 33" that were of similar or lesser proportions and they were listed between 17-20 lbs. I don't know about that, seems high. This one taped out at 34 1/4. I can't imagine it was less than 15, but if those other estimates I saw were accurate I guess 18 is not out of the question. A giant fish anyway, and more importantly, flawless. And fought like a tarpon, bananas!