Don't Spread Didymo

Boulder Booger: This invasive species of algae, commonly known as "rock snot," forms large mats on the bottoms of lakes, river and streams.
New Zealand Fish and Game

Learn how to control didymo algae

Rock snot. Sounds a lot worse than “Didymosphenia geminate,” doesn’t it? This invasive alga is also commonly known as “didymo,” but no matter what you call it, it's gaining footholds in streams worldwide, including some of the most revered trout waters on Earth. The infestation nearest to Missouri is in the White River just south of the Missouri-Arkansas border.

Didymo is bad news for anglers

The jury is still out concerning didymo’s possible ecological effects. But rock snot is definitely bad news for anglers. Stringy alga threads catch on all types of hooks, from dry flies to crankbaits, making fishing nearly impossible.

Please help us keep didymo out of Missouri.

When fishing: comply with the porous-soled wader ban and wash your waders

Didymo: Didymosphenia geminata, an invasive algae, forms slimy mats that smother fish eggs and makes water sports unpleasant.
New Zealand Fish and Game

Contamination of recreational equipment, such as boats, life jackets and fishing gear, particularly waders, is the most common way for didymo to spread.

  • Don't wear porous-soled waders when fishing in trout parks, trout streams, Lake Taneycomo and buffer areas. Learn more about the porous-soled wader ban.
  • Treat your porous-soled waders to avoid spreading didymo in Missouri.

At home: check and clean your gear

  • Check all gear and equipment after use and remove any visible algae. If you notice algae on your equipment at a later time, do not dispose of the algae by putting it down a drain. Dispose of it in the trash.
  • Clean all equipment with a 2 percent household bleach solution, 5 percent saltwater solution, or dishwashing detergent. Allow all equipment to stay in contact with the solution for at least three minutes. Soak all soft items, such as felt-soled waders and life jackets, in the solution for at least 20 minutes. Dry all equipment in sunlight for at least 48 hours.
  • Consider replacing felt-soled waders with a new, environmentally sensitive alternative.