Open Spaces: Felt-free for Aquatic Species

Felt-free for Aquatic Species

On Jan. 1, Alaska and Rhode Island became the latest states to ban felt-soled wading boots, popular because they offer anglers good traction on slick river beds.

Turns out they can also offer rivers something less attractive: Invasive species.

Felt-soled bootsA pair of felt-soled wading boots. Phot: Cheryl Anderson/USFWS

The soles are known to provide an ideal vehicle for spreading tiny invasive species that can cause big problems. Invasives such as:

  • New Zealand mudsnails. These tiny asexual snails don’t need another snail around to reproduce and can reach densities as high as a half-million per square yard! At those densities, they can literally starve a stream: No algae and detritus for aquatic insects means no food for fish.
  • Didymo, a.k.a. “rock snot.”  Forming a thick stringy mat over rocks and other submerged surfaces, this diatom can completely smother a lake or stream.  Didymo is native to some parts of Alaska, but has been spreading and growing more aggressively in recent years. 
  • Myxobolus cerebralis. This parasite infects trout and salmon, causing skeletal deformities and neurological damage, especially in young trout. Infected fish swim in a corkscrew-like pattern (hence the name “whirling disease”), making feeding difficult and increasing their chance of being eaten by predators. This whirling disease pathogen sticks to felt soles more readily than other wading equipment materials and has been confirmed in southcentral Alaska.

Maryland and Vermont have already banned felt-soled waders, and more states are considering such rules. A didymo invasion prompted New Zealand to ban felt-soled boots in 2008.

Members of the fishing community, made up of many conservation-minded individuals, have largely supported the move away from felt. The fishing industry is producing waders with non-felt soles that still provide good traction, so felt may be on the way out.

It won’t solve the current invasion of non-native species, but every little victory in the battle against dangerous invasive species is big. 

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Last updated: June 21, 2012