Golden Stone or Giant Western Golden Stone
Introduction
This
hatch occurs in our area on the Yellowstone
River, Boulder
River, Madison
River, Stillwater River, and some of the other freestone streams.
There are two different Golden Stone hatches the first is the Golden Stone or Calineuria californica which hatches in the early summer often seen along side the Salmon Fly usually late June to early July.
The second is a lesser known, but very important speices the Giant Western Golden Stone or Claassenia sabulosa. This species is nocturnal in nature and interestingly the adults have very rudimentary wings and skitter across the waters surface. They are also highly carnivorous eating other insects. This hatch occurs in abundance on the Yellowstone River from late July through August. Trout often mistake our hopper patterns for this species of goldens.
Nymph Stage
All stone flies have an incomplete life cycle meaning there are
only three stages of development egg, nymph and adult. In the nymph
stage the Salmonfly can live for between 2 to 3 years developing underneath
the waters surface. As nymphs they feed on stream debris and drifting
detritus. Stonefly nymphs need highly oxygenated, clean water and
spend much of their time underneath rocks located close to fast riffled
water. If swept off a rock the stone fly nymphs are terrible swimmers
and can only hope to find solid ground before an observant trout
picks them out of the drift as an easy meal.
Emergence to Adult
As the time of emergence draws closer the nymphs begin to congregate towards the banks of the river or stream. The Giant Western Golden Stone hatches in the evening or even at night. The Golden Stone typically hatches during the early morning hours the nymphs will then crawl out of the river and onto trees or rocks where they shed their exoskeleton. They will then dry their wings and begin mating. As new adults they are very clumsy and often fall into the river becoming a quick meal for hungery trout. As both of these species are poor aviators a try fly that is fished with a twitch can be highly effective.