Nymphs: Yellow Sallies
The nymphs of yellow sallies have adapted to a wide variety of habitats. They most often occur in areas with a gravel or rocky bottom and moderate to fast currents. Most species are more abundant in cool mid-to-high elevation streams than in warm low-elevation rivers.
Little yellow stone nymphs, like yellow sallies, are common in stream drift, making them available and important food items for trout. As they reach maturity, they begin migrating to shoreline areas in preparation for emergence. This further increases the number of drifting nymphs, and it is an excellent time to fish nymphal imitations.
The emergence of yellow sallies usually occurs in typical stonefly fashion: the nymphs crawl out of the water onto shoreline rocks or vegetation where the adult then escapes the nymphal shuck. However, a few species actually emerge in open water in the surface film, just like many mayflies. This is unusual behavior for a stonefly, and drifting emerger patterns become just as important during this activity as during similar mayfly hatches.
Adults: Yellow Sallies
After emergence, adult yellow sallies hide on streamside foliage. A quick way to check if adults are present is to simply look on the undersides of leaves of streamside shrubs and trees. The most obvious and important part of the little yellow stone’s life cycle is egg laying. This is when swarms of adults congregate over shallow riffles and runs. After a short flight to gain altitude (10 to 20 feet), egg-laden females set their wings in a shallow “V” and glide gently to the water. As their abdomen breaks the surface tension, a cluster of eggs is released. The females then quickly lift off the water, only to repeat another gliding descent to the surface.
Yellow sallies lucky enough to escape surface-feeding trout will drop five or six times until all eggs have been laid. They then lie spent on the surface where they die. Most egg laying activity occurs in the late afternoon and evening.
Good Dry Fly imitations of the Little Yellow Stonefly are a Yellow Stimulator, Henry’s Fork Yellow Sallie and Lories Yellow Stone. Good Nymphs to use are a Gold Rib Hares Ear or a Small Golden Stone Nymph.