Isonychia Beaver (Tutorial)

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Re: Isonychia Beaver

Post by narcodog » Tue Jan 04, 2011 8:41 pm

You won't believe this but Schweiberts use of the partridge is the same I have been using for sometime. I have a firey dyed partridge that I use. :D
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Re: Isonychia Beaver

Post by letumgo » Tue Jan 04, 2011 11:35 pm

I've also been playing around with a wiggle-tail version of this fly. I came up with an easy way of making the wiggle-tail extensions using 26 gage craft wire, instead of destroying perfectly good hooks (see link below for details).

This version was tyed on a Mustad R50 hook (size 14), and the hackle is English Grouse Coverlet feather (rich mottled brown color).
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Re: Isonychia Beaver

Post by kanutripr » Tue Jan 04, 2011 11:54 pm

OK that is AMAZING! Gotta try that one!!!

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Re: Isonychia Beaver

Post by redietz » Wed Jan 05, 2011 1:20 am

Interesting that no one has mentioned peacock herl as a body. None are a flymph, but three of the most effective imitations of an iso nymph are the Zug Bug, the Prince Nymph and the Leadwing Coachman.

It's the first hatch that I learned to identify thirty years ago, and still one of my favorites.
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Re: Isonychia Beaver

Post by michaelgmcgraw » Wed Jan 05, 2011 9:55 am

Whats the difference between the Mustad R-50 & the R-90 ? BTW the ISO"S are a hot fly on one of the small creeks I fish.
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Re: Isonychia Beaver

Post by William Anderson » Wed Jan 05, 2011 10:23 am

Ray, wow. Thanks so much for such an exhaustive and informative response. Now I'm all excited for spring just to get to fish this hatch. Really, the research is exactly what was needed. I don't have Schwiebert's nymph volumes, but they've always been on my list. Thanks for putting so much energy into this question. I've fished this hatch in the past with wingless wets, which is why I'm wanting to know how the flies. I've tied these with dun body colors and slate gray hackle, just because I suspect that some end up in the water and they've worked.

That wiggle version is really nice. Looks like it would take me 30 mins to tie, but I may have to just to do it.

Thanks again, and I hope there are lots of others who will continue this post with more information the hatch.

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Re: Isonychia Beaver

Post by Jerry G » Wed Jan 05, 2011 10:33 am


The R50 is referred to by Mustad as a wet-dry hook. The container label still has the 94840 designation also. In comparing to the old 94840 hooks the R50 would appear to be the same wire size and perhaps just a tad shorter in length but having the micro barb.

The R90 by picture appears to have the same round bend as the R50 but is of a much heavier wire. I believe Mustad describes it as 4 heavy and is their nymph entry.

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Re: Isonychia Beaver

Post by hankaye » Wed Jan 05, 2011 11:27 am

Ray, Howdy;

More questions, I like the 'wiggletail', went an read the how to part but got lost at the how to attach the tail to the body.
does it do it 'magically? How did ya manage that part ... :?:
just askin' ...

edit to add; Sorry but when my brain thinks of a question I sometimes forget to mention other mentioning how fine the tail twicher looks, and the amount of envy I have for your skill level (HUGE!!!).
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Re: Isonychia Beaver

Post by dennis » Wed Jan 05, 2011 11:52 am

letumgo, I really like the look of your flies. You are very talented. The Isonychia is one of my favorite hatch"s on my home river. I have seen them hatch by migrating to the shallows and crawling on rocks, logs or other obstructions. I too thought this was there only way of hatching until reading Hatches by Caucci & Nastasi back in the 70's where they mention they also emerge in relatively fast runs like many other mayflys. We have both bicolor and sadleri species on my home waters and the Leadwing
Coachman with traditional slate colored wings along with a few with white quill slips for murky water conditions is my go to fly ninety percent of the time till the duns appear then I use a Dun Variant in sizes 10-12.

narcodog mentions that the dubbing looks very similar to the Conover dubbing that Joe Fox at Dette Flies sells. A muskrat and red wool. I also noticed this when I first seen your pattern. I plan on using this dubbing mix for a few drys to try during late May into June when the Slate Drake's the most prolific. I will use a brown hackle front due to the front brown legs of the insect and a golden badger to make an impressionist pattern John Atherton mentions in his "The Fly and the Fish" also to honer the original Conover pattern of Scotty Conover from the Catskills.

Great Post, Dennis
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Re: Isonychia Beaver

Post by letumgo » Wed Jan 05, 2011 12:57 pm

Michael - Jerry has given you a great answer regarding the difference between the R50 and R90 hooks. It is my understanding that they are both standard length hooks hooks (identical in size/shape) but the R90 is made with heavy gage wire (4 time heavier = 4XH).

I believe that all of theses models have the same shank length and bend diameter, for a given size. The difference being the diameter of the wire used to make the hook.

R30 (standard length/two extra fine wire) = light dry fly hook
R50 (standard length/standard weight wire) = standard dry fly hook
R60 (standard length/one extra heavy wire) = standard nymph hook
R70 (standard length/two extra heavy wire) = heavy nymph hook
R90 (standard length/four extra heavy wire) = extra heavy nymph hook

It is a good way to have a pattern fish at different levels, just by picking which hook thickness hook you want to use.

Link to Mustad's Interactive Hook Guide (detailed information about each model)

Hank - Yes, I use magic (just kidding). I use a loop of beading cord (used for making beaded bracelets) to attach the wiggle tail to the hook. Very simple process. I will take a picture later to show the intermediate step.

William - These only take about the time to tye two normal flies. Once you start cranking them out, you can probably do these in under five minutes. It is just like tying two flies.
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