....................... ......Fly Fishing Yellowstone National Park
Catching Yellowstone Trout in Cold Water - Part 9
So far, i have only discussed fishing cold water when no hatches are occurring. Everything has been to do with getting a nymph or larvae imitation in water that is moving slowly. Hatches can and do take place in cold water.
Midges can and do hatch in water that is in mid to high thirties, in terms of degrees Fahrenheit.. Winter stoneflies (of two different families) can and do hatch in water in the low forties. Some of these are wingless. They look a lot like ants. If there is snow on the banks and rocks in the stream, you can usually see the dark adult stoneflies crawling around. Like all stoneflies, these crawl out of the water to hatch. When they do crawl out of their normal hiding place and migrate to the banks to hatch, the trout know it. The third type of insects to hatch in cold water are some species of Blue-winged olives. They can and do hatch when the water is between forty-five and fifty degrees.
I will discuss fishing each of these hatches starting with midges. The first couple of years that I fished Yellowstone National Park when the water was very cold, I ignored the midges. I certainly wasn't in a minority. I think most anglers ignore them, especially in Yellowstone, even the ones that swear by them in the tailwater streams. Anglers have very good success with midge imitations fishing the local Wyoming and Montana tailwaters.
One problem with them is that midge flies are tied and sold that don't even resemble a midge. Most of the commercially available midge patterns are colorful and flashy to attract the angler, rather than the trout. If anglers fished any of these types of flies in spring creeks, for example, they would find the results would be completely different. Midges are not flashy and colorful. In fact most of them are dull colors of cream and light greens. There are also red ones that imitate the blood worms, but even they are dull red.
There is a factor involved that does add what could be considered flashy, I suppose. Midge pupae reach the surface of the water to hatch with gas that provides buoyancy. They can't swim as such. The tiny bubbles from this gas appears to make the pupae glitter. That is why we add a tiny bit of glitter to our "Perfect Fly" midge pupae. The peacock herl thorax serves several purposes. It provides a glitter effect that looks very similar to the air bubbles that accent the pupae to the surface to hatch. It also imitates the thorax about to split open with wings very well.