Mayfly madness on the Big Horn River

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By Gordon Rose

I recently nominated three military vets from my Healing Waters program for a regionally sponsored three-day trip next week to Ruby River in Montana.

The vets are rank beginners, so I took them on a “training” trip to the Big Horn last Friday. My plan was to float the entire upper 12 miles of the river in order to give the guys as much boat fishing experience as possible.

While buying lunches and licenses in Ft. Smith, I noticed the heavy dark cloud cover and relative calm air; perfect conditions for a mayfly hatch on the Big Horn this time of year. I reconsidered my plan for a moment because the 12-mile float at the current flows doesn’t allow much time to stop and wade fish. If a good hatch comes off, it’s nearly impossible to fish to the rising trout from the boat. You have to stop, get out, and wade close to the fish in order to make multiple, very accurate casts to individually rising fish. I thought “Oh, whatever. There will still be plenty of fish ignoring the hatch, and these guys need to practice boat fishing.” Oops!

We floated the first mile and a half of the river without a strike, while I noticed lots of fish in shallower water along the banks feeding on the surface. Freshly hatched mayflies were starting to cover the water everywhere I looked. This was going to call for a total change in itinerary! I decided that we could stop for a couple of hours and I’d make up for lost time later by just turning the boat around and rowing down river as fast as I could.

We backed into the lower end of a gravel bar in the middle of the river where I knew that fish liked to move onto from deep water in order to feed on the surface. Sure enough, I dropped the anchor and we looked back upstream on the bar about 20 yards to see a dozen fish feeding on the surface. It took me about 10 minutes to re-rig the fly rods from nymphs to a dry fly set up with a 5x tippet and a No. 18 parachute blue wing olive mayfly pattern. As we waded towards the fish, there were now about 60 trout on the bar rising to the freshly hatched mayflies!

We ended up staying there for about three hours casting to those fish. It was actually quite difficult for the vets, but they had an awesome time and learned a lot. They finally caught a half dozen fish and one vet ended up landing a 21-inch brown trout on a No. 18 blue quill pattern. He had never touched a fly rod until four hours prior to catching that fish!

I can now pass on two great secrets about dry fly fishing to you readers having to do with casting accuracy and fly color.
When the water is literally covered with natural insects, your casts to a rising fish have to be extremely accurate. The fish has to see your fly the moment he looks up, or he will see a natural insect first and grab that instead. I remember a client years ago who said “I don’t think you’ve given us the right fly. I keep seeing the fish rise to something else only two inches from my fly!”

My response: “If you were a trout feeding on mayfly duns, and you saw a beautiful, freshly hatched natural and then a hook with chicken feathers wrapped around it floating close by, which one would you eat every time?”

You have to pick out one rising fish, observe his feeding rhythm, put your fly in front of him when you think he’ll look up again and then pick up your fly to recast the moment it floats past his tail.
Regarding fly color, remember a prior column where I wrote about the importance of prioritizing silhouette, color and size – in that order. We had flies of the right silhouette and size, but not the right color. Oddly, the color was fine for the fish, but not for us.

On that dark, cloud covered, day of low-light conditions, there is always a very reflective glare on the water’s surface; almost like a mirror. In those conditions you have to use a fly whose wings are very dark‚ black is the best!

Everything else is impossible to see, especially if it’s only a size 18. If casting accuracy is so critical, how can you know how accurate you’re being if you can’t ever see your fly on the water?
Of course I’d prepared the vet’s fly selection of the day with dozens of nymphs, but no dark-winged dry flies. Once I finally located a couple of blue quills with the darkest wings possible, the vets finally were able to get their casting rhythm down and catch some fish.

Lastly, I have just a little humor for you. I took two different vets out the week before. We were nymph fishing a similar mid-river gravel bar about 30 yards from shore.

We noticed what appeared to be a small muskrat swimming in the river, but it oddly seemed to be swimming straight toward us. As it got closer, I noticed that it was a large gopher which had apparently fallen off a tall bank near the shore.

It was clearly a poor swimmer, and as it got about three feet away I saw a look on its face which clearly said “Help me! Help me!” I pulled my net from my wading belt and scooped the little lady out the water. She just shook herself off, rested for a few minutes and then climbed to the rim of my large boat net to survey her current situation. She looked back to shore and then gave me a look which clearly told me “Can you take me home now?” I waded across the gravel bar and dumped her in the grass along the shore.
Every time I float fly that spot I’ll think of whether that gopher is sitting on the high bank watching me float by. I bet if she is, she’ll not be perched so close to the edge of the drop off into the water ever again!

For me, that was the catch of the day! For the vets, they preferred the trout which was landed off that gravel bar only 10 minutes after I released my new little BFF gopher girlfriend.

GORDON ROSE works as a commercial fly tier and operates Sheridan WYO Healing Waters, part of a national nonprofit organization which teaches disabled military veterans fly fishing, fly tying and fly rod-building as part of their therapy.

By |May 23rd, 2013|

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