Not long ago, felt was the choice when it came to fly fishing wading boot soles, but that was before rock snot and before snails tinier than midge larvae began hitchhiking on our gear. As Brett Prettyman points out, since both Simms and Patagonia make wading boots with soles that are designed to impede the transport of invasive species, you have to ask yourself why you wouldn’t choose the healthier alternative. After all, it is the spread of hazards that aren’t yet on our radar that might end up being most damaging to our trout streams. “‘Felt is basically a dirty sponge that is very difficult or impossible to disinfect,’ said Chris Wilson, director of [Utah]’s Fisheries Experiment Station and one of, if not the most, knowledgeable experts on whirling disease. ‘It is a great media for spreading a great number of things.’ Those ‘things’ include whirling disease and New Zealand mud snails, both of which can negatively impact trout fishing. Who knows what other diseases and exotic species are out there that could be transported by felt-bottomed boots.” In The Salt Lake Tribune.