Fly Fishing Advice at Orvis

The Rising Problem of Invasive Species

As the result of the emerging threat posed to our fisheries by various Aquatic Nuisance Species (ANS) such as New Zealand mud snails, the whirling disease parasite Myxobolus cerebralis, and Didymo (filamentous algae), many anglers, guides, outfitters, lodge, and fly shop owners have raised concerns regarding the proper care of angling equipment to help prevent the spread of these nasty aquatic hitchhikers. 

Inspect, Clean, and Dry all Fishing Equipment

Unfortunately, there is no safe and simple, universal, one-size-fits-all, silver bullet solution for neutralizing these various invasive aquatic flora and fauna, and the chemical solutions that do come the closest to providing this guarantee are extremely harsh on equipment and not safe for the environment.  For example, while soaking wading gear in a solution of chlorine bleach and water will kill the whirling disease parasite; repeated use of this mixture will destroy the wading gear.  So, what can one do?  The most workable solution is to simply inspect, clean, and whenever possible dry your fishing gear when moving between fishing locations, especially when moving from waters where ANS are known to be present. 

ANS can hitch a ride in mud, debris, aquatic vegetation, and in water.  In the case of boats, make sure all water is drained from boat and live wells.  Inspect the boat and rinse the boat and trailer at a car wash or with a garden hose.  For waders and angling gear, before you leave the river, rinse off the mud, debris, and vegetation.  Inspect waders and boots to make sure nobody is hiding in the crevices and seams.  A soft brush kept in the wader bag is useful when cleaning the boot seams.  If possible, dry your gear out between trips.  If sportsmen perform these relatively simple tasks, they’ll be doing their part to help prevent the spread of Aquatic Nuisance Species. 

What about Chemical Treatments? 

It is true that various chemical treatments have been identified that will kill some ANS such as Formula 409 for mud snails and chlorine bleach or Sparquat for whirling disease spores,  The fact is that these chemicals are harsh on equipment and may be harmful to the aquatic ecosystem.  Can you imagine what the fishing access site, nearby riparian zone, and river water might look (and smell) like if everyone that got out of the water doused their gear in bleach and Formula 409?  The best approach for the angling and sporting public to help prevent the spread of Aquatic Nuisance Species is to Inspect, Clean, and Dry, simple guidelines of the Federation of Fly Fishers campaign - the Clean Angling Pledge. Federation of Fly Fishers and Trout Unlimited have joined together to request that every angler join in this effort by signing the Clean Angling Pledge which can be viewed and signed online at

Eurasian Watermilfoil Didymo New Zealand Mudsnails
Eurasian Watermilfoil - Photo by Robert L. Johnson, Cornell University Didymo - Photo by Sarah Spaulding USGS/EPA Whirling Disease Infected Trout - Photo by Barry Nehring, Colorado Division of Wildlife New Zealand Mudsnails - Photo by D.L. Gustafon

For more information on Aquatic Nuisance Species visit

Dave Kumlien
Executive Director, Whirling Disease Foundation

Dave Kumlien is a former fly shop owner, current Montana fly fishing outfitter and was a charter member of Orvis’s Endorsed Lodge Outfitter and Guide program. He is currently the Executive Director of Trout Unlimited’s Bozeman, Montana based Whirling Disease Foundation.

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