I would think the percentage of fisherman coming to Missouri fishing, that have been in Didymo infested waters is minimal at best. If I fish Taney, then head to Crane Creek, I am not spreading Didymo. It's not there. If one fisherman fished Didymo water, then fished Taney, I guess in theory, he could ruin Taney forever, but I doubt it. There I said it...phew....