Bugs - The Yuba Skwala Stone

SKWALA STONES

Entomology:
Skwala Stonefly
Perlodidae
Order: Plecoptera (Stonefly)
Family: Perlodidae
Sub family:perlodinae
Genus: Skwala
Species:Americana (American Springfly)



It’s late January and the word on the streets is that the Skwalas are out. It's time to tie up some big bugs and get ready. The last time I fished the Yuba I picked up a couple of nice fish with a Mercer’s Skwala Nymph. It’s a good one.

The Skwala activity on the Lower Yuba River can start as early as late December and then transitions to "strong" activity beginning mid February and generally lasting until mid April. The Skwala is a very important hatch in that it is the first big meal of the season. Regardless of how many adults there are, the fish know they are there. Fish make their living on eating the predominant insects and food sources of the season.

If you’re fishing on the Lower Yuba River and someone asks you what pattern to use for the Skwalas, tell him without breaking into a grin, “Try a Skwala Emerger”. Like all stoneflies, Skwala's crawl from the river and actually hatch on riverside rocks or vegetation, so there is no emerging period when they are available to trout, just the nymphs and adults. Hence, no emerger patterns for Skwalas.


Skwala nymphs are predatory and feed on other aquatic insects during their one year spent maturing in the river. I heard from Frank Rinella that Ralph Cutter has a theory that the Skwalas are munching on the caddis and that’s why we haven’t seen as many of them on the river. Who knows? If that's even remotely true, there must be a lot of Skwalas!


Once spring starts knocking on the door they crawl from the water, hatch as adults, and go about the business of finding a mate, an interesting process for stoneflies. They will locate mates by "drumming" their abdomens on the branches of bankside willows, a potential mate will "drum" back, and this heated "Mating Game" will continue until a match is made or they give up and try to find another mate. Another interesting aspect of skwala stoneflies is that only the females have wings, and is one of the reasons that skwala dry fly patterns will often incorporate a black egg sack. The females are the ones most often available to the trout while the males are busy crawling around on dry land, drumming up lost love.


In Mid-February (on the average every year) the water temps start to increase a bit. Water temps are always the impetus for insect emergence. The Skwala nymph starts getting active around 39-40 degrees. Just think about it. It has been a while since the trout were gobbling up eggs and they have been eating small mayflies for awhile. The rainbow trout and steelhead are getting into their pre-spawn mode and the larger trout are thinking about perpetuating the species. Their metabolism is starting to pick up a bit from the previous two months of colder water temps and they will most certainly chow down on larger types of food sources and also to prepare for the spawn. Once the water temps start coming to about 45 degrees the bug of choice is the Adult Skwala. Time to tie, buy, beg or steal Skwala Dry patterns.


The Skwala nymphs prefers fast moving, well aerated, cold, clear water with a rock and cobble bottom. This is probably why the Skwalas are present on the lower Yuba River. The nymph generally emerges in the late afternoon and into the evening. Stonefly nymphs are generally pretty poor swimmers and Skwala's are no exception. They swim, or at least attempt to, in a side-to-side type motion with most of the movement taking place on the upper body and the tail kind of dragging along.


They are still prone to getting caught up in the drift once they become very active and start heading for the banks. Fish will stage in the shallow riffle areas and will actively search for the adults drifting along the banks and under the willows. Be careful not to step and wade into areas that could be holding opportunistic fish looking for a big meal.


The Skwala hatch on the Lower Yuba River is the real deal! It is not a prolific hatch, yet it is an important food source that helps kick off every new season. Get ready! They're coming!