The fabric edge is coming unglued? Or the fabric edge is fraying?
The first *may* be cause bigger problems; the latter is cosmetic.
If the former, I'd see about tacking it down and sealing it (in fresh water it may be less of an issue; salt water will leave salt crystals in the joint which will further open up the void. Fresh water won't.) If it's open to the onrushing water as you move, the water pressure may increase the separation.
The latter is just loose threads falling out of the fabric. No biggie; cut or carefully burn them off. A buddy uses Krazy Glue to seal the cut fabric edge as this occurs, but I don't think it's really necessary.