That's Didymosphaenia, and yes, it is a Northern hemisphere species of diatom. Strictly speaking it's not an invasive species in the US but one wherein something changed. It's a puzzler because it was known from only a few very low nutrient and cold streams in high mountains, e.g. along the continental divide in the US. How it ever changed/adapted to the variety of streams it has now infested remains unknown. It has certainly spread like wildfire in the US. In the last few years it's gotten to many NE rivers including such as the Battenkill, Esopus, and the Upper Delaware. And yes, those all are famous trout and fly fishing streams. Trout Unlimited at least, and some other groups, do think that felt soles could be the main culprit in spreading them. TU has been working hard not only to discourage the use of felt soles but also to develop specialized rubber compounds that will still afford a good grip on slippery rocks without a porous composition that could entrap the diatom for accidental transfer. Could this work? The best evidence so far is from New Zealand. A very strict program of thoroughly cleaning and decontaminating flyfishing gear there has kept infestations out of rivers other than the original ones... It wouldn't surprise me to see some paddlers' neoprene boots with the new rubber compounds out and around soon. Oh, one of the best sources for information on this subject can be gotten from the Federation of Fly Fishermen based in Montana. They have a CDROM of really good info on this subject and their website has a lot of info... Joe Pylka -----Original Message----- >From: Paul Hayward <pdh_at_mmcl.co.nz> >We have a similar situation here in NZ, with a delightfully invasive river >weed called 'rock-snot' (not, perhaps, in scientific circles). > >It seems to have been a gift from the Northern Hemisphere - probably on some >trout fisherman's felt-soled river waders - which we have recently banned. >(Closing the stable door...) > >When moving between waterways, we are now all washing our kayaks & gear (and >any other road-mobile boats) in solutions of household bleach. Most people >think this is environmental wishful-thinking, as the millions of water fowl >are proving damn hard to train... > >Best Regards >Paul Hayward Auckland, New Zealand >*************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Thu Jul 16 2009 - 21:42:14 PDT
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