Hey, it’s a great day for fishing; the sun is shining and the birds are singing, You grab your fishing pole, tackle, hip waders, a quick stop at the sports shop and you’re off to the river. You haven’t been fishing up Hellroaring Creek for a couple of years but it used to be a good bet for catching trout supper.

It takes a bit of time to get there, most good fishing spots do in the East Kootenay, but you don’t mind. As you step out of the truck, you can feel the anticipation of that first tug on the line. You grab your gear and head down the bank to the water.

What you see in the creek stops you in your tracks. The last time you were here the rocks sparkled in the crystal clear rushing water. Now, well, it was like nature had caught a nasty cold, you know, the kind little kids get with the runny green-brown stuff. The rocks are covered in what looks like slime; something in the water environment had definitely changed.

You remember a deep quiet pool in the river, where the creek bends and the water first laps the shore in waves and then settles to calm. It used to be a fine place to fish. When you get there, the situation is even grimmer, not only did nature have a cold but the old tissues were left all over the shore. Ewww gross!

Rocksnot, scientific name Didymosphenia geminata, is a type of freshwater algae believed to be native to parts of the northern hemisphere. However, Didymo blooms described in the story above are phenomena of the past 20 years. These blooms coat the river bottom and leave tissue like debris along the shoreline.

The first Didymo blooms in B.C. were documented in Central Vancouver Island rivers in 1989. Didymo quickly spread throughout rivers in British Columbia, including Hell Roaring Creek and St. Mary’s River here in the East Kootenay.

Cold, clear, rock bottom mountain rivers and streams with areas of sun exposure are ideal Didymo habitat. Didymo grow as individual stalks attached to rock surfaces and form hemispherical colonies. When conditions are favourable, the stalks join to form gelatinous cotton wool like masses several centimetres thick that smother the rocky bottom. This growth prevents oxygen movement from surface waters to the gravel egg incubation areas of salmon and trout. The infested environment also reduces natural habitat and food sources for young fish making it difficult for them to survive.

To date, no known changes to environmental conditions have been found to explain Didymo blooms. However, a strong correlation has been found between the increase in Didymo bloom and the widespread commercial introduction of felt-soled fishing waders, in the late 1980s. This correlation is so strong that countries like New Zealand and many U.S. states such as Maryland, Vermont and Alaska have banned the sale and use of felt-soled waders.

Because the Didymo algae can survive in any moist environment for several days, fishermen are encouraged to clean, drain and dry their gear, before the next use. Non-porous gear can be cleaned in hot water and detergent or soak in a two per cent bleach solution. Porous gear should be washed in very hot (45C) water and detergent for 30-40 minutes or frozen solid  for a minimum of four hours.

Since the drying of felt waders and bleach and detergent penetration of felts can be problematic, freezing gear solid is considered to be the only fully effective solution. Fortunately, other aquatic invasives that are of concern to North America such as New Zealand mud snails and Zebra/Quagga mussels which can hitch a ride on felt-soled waders also succumb to freezing.

Fishermen are encouraged to purchase and use rubber soled waders instead. With Didymo and other invasive species showing up in Kootenay waterways, to reduce the risk of spreading aquatic invasive species, it is still important to clean, drain and dry rubber soled waders, as well. If you find plant debris on your gear, dispose of it in the garbage and not down the drain.  Together these measures will help to keep East Kootenay waters clean and fish friendly.

The East Kootenay Invasive Plant Council and its Outreach and Education program gratefully .acknowledges the financial support of Columbia Basin Trust, which supports efforts to deliver social, economic and environmental benefits to the residents of the Columbia Basin.

By Pauline Artifacet,

EKIPC Outreach Coordinator

Images by: David DeRosa and Julianee Leekie

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