AIS

They travel in the water trapped in felt soles, in wader booties, in boat livewells and on trailers. A single move from an infected river to a clean one can establish a population that permanently changes the fishery.

This is not an abstract concern. Whirling disease has devastated wild trout populations in several western rivers, zebra mussels have spread across most of the eastern United States, and didymo carpets riverbeds in nuisance blooms. Felt sole bans exist entirely because of this.

The standard protocol is clean, drain, dry. Scrub gear, drain any standing water, and let everything dry completely before fishing different water. Freezing overnight also works.

Many states now run inspection stations at boat ramps and some require a decontamination certificate to launch. The rules differ by state and change often enough that checking before a trip is worth the five minutes.