Welcome to the Forum. Sorry I can't be of help in ID'ing your line, but others on this Forum surely will.
Good luck with your Florida Gulf fishing. I've really enjoyed fishing Pine Island Sound, Sanibel and Captiva over the years. It's always been the snook for me; took one trip to Boca Grande (by default, everything else was blown out), and saw lots of tarpon (one of my absolute favorite fish), but they weren't interested in anything I had. Great sight, though. Like being in an aquarium.