....................... ......Fly Fishing Yellowstone National Park
Fly Fishing Yellowstone - Spotted Sedge Adults
When Spotted Sedges hatch, they hatch mid stream much like a mayfly. They don't stay on the water very long at all. As soon as their wings are dry they are gone. Just how quickly this happens depends on the water and air temperatures. In reality, the trout probably eat far more of the emerging pupae than they do the newly hatched adults before they depart the water. After they leave the water, they head for the streamside to mate in the trees, bushes and grass.
After the insects mate and the female's eggs are ready, she will fly back over the water and deposit them in the same type of place she hatched from. They do this two ways. Some of them dip down and touch the water with their abdomens and knock the eggs off so to speak and others dive to the bottom and paste their eggs on the substrate and objects in the water. I think this is more to do with the particular species of Hydrosyche but I am told by entomologist that some species do it both ways.
As a general rule, the females do not start depositing their eggs until very late in the afternoon usually just before dark. The activity usually continues on into the evenings. On cloudy, rainy days the hatch and egg laying activity seems to start earlier in the afternoon. In fact, the hatch is usually still underway during the time the females start to deposit their eggs. Under these conditions, you need to determine what the trout are keying in on, the egg layers or the pupae. You should be able to see the trout eating the egg layers. They usually make a splashy rise when they feed on the surface. When they dive to deposit their eggs, you would not be able to see anything occurring other than a possible flash from a feeding trout.
Fishing the Adult Imitation: I suggest you first try our "Perfect Fly Spotted Sedge Adult" fly. If the activity is fully underway, you should get plenty of action. In rough pocket water or runs and riffles, i suggest you fish up and across making a lot of short cast. In smooth water, I suggest you make longer, down and across presentations. It is usually not very difficult to catch the trout feeding on the egg layers. If you put the fly in the area you see the fish eating them, you have completed most of your job. The sun has set and it is usually almost dark before the best action begins, so the trout cannot see the fly very well. The biggest mistake you can make is to start fishing to early. When other anglers are dinning or having a drink at the local bar, that is about the time you need to start fishing for the egg laying Spotted Sedges.