October 20th, 2008

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Rock-Snot
By T_Loop, WVA

Ok, here we stand on the threshold of another environmental disaster. Here in West Virginia we have deep mines, strip mines, poor logging practices, silt and now didymo. Seems like every time you turn around there's another problem with something hurting our trout streams.

This new or not so new invader is an algae that was reported as much as ten years ago, but lately is spreading at a rate that is very alarming. And not only in here but in many eastern and western trout streams and what is reported about it appears to be off by as much as 50% on the low side.

'Rock-Snot' they call it, didymo is an invasive algae that harms the stream environs in many ways, everything from water chemistry to fish and insect size. Mayflies, caddis flies and stone flies numbers decrease as the stalks of the didymo algae spreads. The stalks left don't degrade very fast and trap silt and other debris, so although species like midges can actually benefit by that, any critter that requires clean cobble type stream bottoms suffer.

Unfortunately the research and facts for this invader is very lacking. New Zealand is probably the front runner in research and control on the subject but early tests are not very promising on any solution to this growing problem.

It can spread in water that was previously thought not to support it. The idea that it could only thrive in cold low nutrient waters is turning out to be a wishful pipe dream. First thought to spread best in stable tail waters, it is now being found in much more diverse waters, everything from drainage ditches to municipal water systems.

Something that may help, as far as West Virginia water ways is concerned, is fluctuating water and temperature levels. Water that is subject to floods seems to scrub the cobble-stones and low water dries out the stream beds, so this may help to control the growth and spread of didymo.

The best prevention at this time seems to be to clean and dry your gear, especially your felt soled waders or wading boots. There are a number of web sites and bulletins that explain this process. ~ T_Loop


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