Dry Fly verus nymph
I have read several posting stating that the water levels are down and that the majority of the fish are being caught on the dropper fly which has usually been a nymph instead of the dry fly.
One post was describing that once he switched over from a dry to a nymph the action took off and and "you know what that means"
I do not know what this means, are we entering a transistion from dry to nymph because of water levels or are the fish biting the nymphs more because they do not see you as easily.
I am planning on fishing next week while I'm on vacation and would really like to understand if the dry fly versus nymph is water level related or something else.
I'm not really sure why it works, but it does. I've seen trout come up to inspect the dry and then turn and take the nymph. I've caught far more trout on a nymph than on a dry, and usually in that configuration. I've also been in a few situations where I've caught more on the dry than on the nymph. This eventually leads me to cutting the dropper of and going dry only. Think of it as being a way of fishing two flies to find out what they are going after.
In case you are not sure how to do this, the method I use is to tie about 18" of tippet (I usually go with 5 or 6x in the park) to the bend of the dry fly hook, and then tie on the nymph. The most important thing though is to look at the water and figure out what is going on. I've actually fished a dry with a terrestrial dropper, just don't put any floatant on the terrestrial fishing it as a wet fly.
I really don't know why it works but it will. I will say that I hook more fish on nymphs than I do dry flies. I fish big weighted flies (#4  hooks) all year unless I'm on a small stream. I fish the same rig in high water or low water. I hook about the same number of fish no matter if the water is high or low. I will say that I hook and land better fish when the water is up. I beleive that big fish feed better when the water is up. I'm not talking about flash flood conditions but when the water is up some with a little bit of color to it. When I fish a small stream I will drop down to a #8 or #10 hook but they will still have some weight on them. I spend 85% of my time on Little River fishing. I fish with a dropper fly, both flies are weighted. I do hook a lot of fish with this rig. As far as fly colors and patterns I stay with Stone Flies, black or brown in color, Hare Ears Nymphs in light brown or a Bitch Creek in black. A Prince Nymph works well. Also use a Tellico Nymph. Hope this info helps for later fishing dates...
May God Bless you... John 8:12
n general, there are a few reasons I think nymphs "work" better:
1. >80% of a trout's natural food comes from subsurface items. It's just more of a natural place to find food.
2. Low water: trout are more skittish, not wanting to venture far from cover.
3. Low water, usually means warmer, less oxygenated water: trout move less.
That being said, I still fish dries most of the time in warm weather. Nothing like a spec crushing a big bushy EHC.
I am not a nymph fisherman. I have caught fish on nymphs but my success has been sporadic. It's just going to take MUCH more practice.
Having said that, one of my first fish caught on a nymph was last summer when water levels were low and the water was warm. I had floated a female parachute adams through a pool several time with the same trout swimming lazily up, inspecting it and then going back down to the bottom of the pool. In desperation, I tied on a nymph dropper and the first time back through the same pool, the same trout took the nymph. It was a very visible, slow motion kind of demonstration on the benefit of being able to fish with nymphs. As a general practice, I still prefer fishing dries only but learning to fish with nymphs when they're needed is a must for me. If you can routinely fish the double rig, as danp413 said, it gives the fish both options in the same cast.
Although I much prefer dries, I bought some BHPT yesterday so I still intend to keep plugging on the nymphs.