Pretentious Snobby Bastard Fly Fishing!

Fly Fishing BS => The Gravel Bar => Topic started by: Woolly Bugger on August 13, 2007, 11:09:43 AM

Title: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: Woolly Bugger on August 13, 2007, 11:09:43 AM
Didymo is a single cell algae that is spreading around the coldwater fisheries of the world. Some are saying that it travels from watershead to watershed by boats, fisherman's boots and waders, while others maintain that the true culprit is Canada Geese! The FFF has come out with a resource CD that provides a wealth of information on the subject.

It affects the tailwaters of TN including the Watauga and South Holston, and the Smith River in VA (these are the only streams where I've encountered it...

here are some links for more info...
http://www.flyfishinginnh.com/forum/viewtopic.php?t=2054
http://www.biosecurity.govt.nz/didymo
http://www.fedflyfishers.org/conDidymo.php
Title: Re: The Didymo hread.. Where it is, what it is and how it is spread!
Post by: Al on August 13, 2007, 13:19:07 PM
It was real strong on the Smith earlier this year - but the last couple times out I have noticed that most of it has dissipated. Seems like it comes and goes - not sure why that is. I need to read the links Woolly posted - maybe it will enlighten me.

No matter what - I don't think it is good for the fishery.
Title: Re: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: natureboy on August 13, 2007, 18:19:55 PM
I've seen it on the Pound River and heard it's on the Jackson.
Title: Re: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: Shane on August 13, 2007, 20:43:54 PM
I've seen some tufts of it on The Davidson this year too.


S
Title: Re: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: flatlander on August 13, 2007, 20:52:51 PM
Quote from: bowsreign on August 13, 2007, 16:54:40 PM
I was on the Smith a couple days ago and it was so thick I wasn't able to fish nymphs. About half way between the dam and the first bridge it looks like a cotton field.  >:(

I've heard guys say the same thing about Arkansas...how it has virtually ruined nymph fishing on some of the tail races there.  It's getting to the point on the Holston where you can't fish a nymph on the bottom either.
Title: Re: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: Al on August 13, 2007, 21:31:45 PM
Quote from: bowsreign on August 13, 2007, 16:54:40 PM
I was on the Smith a couple days ago and it was so thick I wasn't able to fish nymphs. About half way between the dam and the first bridge it looks like a cotton field.  >:(

Seems like it has a lot to do with water temp. I just spoke with VDGIF biologist today about it. He is as mystified as we all are - He also thinks water temp of 10-12 C makes it come and go. That explains it thriving up near the Dam and not so bad down in Spec Reg right now. It will probably bloom all over the river again as soon as temps go down this winter.
Title: Re: The Didymo thread.. Where it is, what it is and how it is spread!
Post by: troutphisher on August 15, 2007, 19:17:52 PM
Didymo has hit the upper green pretty bad. Last time I waded that area. it was like walking on greased bowling balls.

In the South Holston, is so thick it completely covers the bottom and some of the trash. I could make out the silhouettes of old tires and wash machines.

In my experience so far, it has been relegated to tail waters in water temps below 60. There farther one travels down the green, the less the didymo is present, and even disappears completely below fish stop.

I wonder if there is a way to raise water temps artificially for some period of time to kill didymo, but not harm the trout? Maybe this could be done cyclically to keep didymo in check.