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This topic is about the Stonefly Genus Skwala

The genus Skwala (Short-winged Springflies) of the Perlodidae family is represented by three species in North America, Skwala americana, the identical looking Skwala curvata and Skwala compacta. Skwala should be included in any comprehensive list of important stoneflies for the western flyfisher. Though often mistakenly thought of as members of the Perlidae (Golden Stones) that happen to hatch early, they are actually quite different and often far more important on many western rivers than their more publicized cousins. Perhaps the most significant factors regarding this growing recognition are their inhabiting tailwaters previously too warm for trout and the lengthening of trout seasons, both relatively recent phenomena. This explains the scant mention they have received (if any) in older angling literature.

Excepting the lake dwelling compacta, they are lovers of cobble bottomed riffles and runs of larger mid to low elevation rivers. Their behavior is consistent with other large stoneflies except that they are more prone to floating long distances as they placidly oviposit, and with the exception of Pteronarcys californica (Salmon Flies) in some locations, they do it in larger numbers. There is usually no challenge to them for the fishes attention until Rhithrogena morrisoni (March Brown) mayflies begin to appear a few weeks later. Their flights occur during the warmest part of the day which usually means in the afternoon, though impressive flights have been observed around the lunch hour. Regardless, they finish well before dark.

The river dwelling adults have smoky brown to brown wings, brown legs, and either primrose (often tinged w/ olive) abdomens ribbed with brown or the reverse in darker strains. The males are brachypterous (Brachypterous: With short or or addreviated wings.), smaller and usually darker. Both sexes thoracic (Thorax: The thorax is the middle part of an insect's body, in between the abdomen and the head, and to which the legs and wings are attached.) ventrals are a curiously marked yellow/dark brown variegated pattern. Gravid females carry blackish pea shaped egg clusters off the tips of their abdomens that are much larger in diameter. Read more...

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The Discussion

EntomanJanuary 16th, 2011, 11:39 pm
Northern CA & ID

Posts: 2604
The genus Skwala (Short-winged Springflies) of the Perlodidae family should be included in any comprehensive list of important stoneflies for the western flyfisher. Though often mistakenly thought of as perlids (Golden Stones) that happen to hatch early, they are actually quite different and often far more important than their highly publicized cousins on many western rivers. Perhaps the most significant factors regarding the growing recognition of their importance are their inhabiting tailwaters and the lengthening of trout seasons, both relatively recent phenomena. This goes a long way in explaining the scant mention they have received in older angling literature.

Where Skwalas are found in such incredible numbers are mostly the low elevation tailwaters. These rivers flowed much too warm in the Summer and early Fall to sustain trout fisheries prior to the extensive dam projects of the 50's and 60's. So... nobody in our fraternity paid much attention to the bug life. Whether the Skwalas were already there and adapted to the cooler water or migrated from higher elevations is an interesting conjecture. A popular theory is that these tailwaters are rapidly evolving ecosystems that are only now settling into their established fauna that include the now very important Skwala and ... trout! It makes sense to me.

In CA, their emergence runs for a few weeks to a month and can start as early as mid January, depending on the year. Years in which we miss a February "false spring" following a cold January can delay them until the end of the month running well into March. These dates are undoubtedly much later north of Southern Oregon and east of the Sierra's. They are reported even later in the northern Rockies.

What little information that does exist about the genus Skwala in flyfishing literature is often misplaced with other genera or treated in short footnotes as insignificant. There also seems to be a lot of confusion among knowledgable anglers between this genus and Paraperla, which is of an entirely different family (Chloroperlidae). Ernest Schwiebert in his revised addition of "Nymphs" listed Paraperla paralella as a hatch of some significance out west. In footnotes related to this species, he mentions that some entomologists are considering placing this species in the Skwala genus. This footnote is the only reference to Skwala in the entire book and the genus isn't listed in the extensive index covering hundreds of far more obscure species. His comment only adds to the confusion. Especially since he accurately describes Paraperla's physical characteristics, which are at odds with those of Skwala. Moving species among genera while retaining their specific names is one thing but moving them to entirely different families already in existence is problematic. Perhaps the confusion comes from shared specific names by the two different genera in older taxonomies that do list Skwala paralella as a valid name that has since been dropped.

What we call them aside, there is no confusion about the differences in their appearance. Paraperlas are very slender (not unlike the dark winter stones) and less noticeably segmented than would normally be associated with Perlodids. They are more monochromatic and usually lack pronounced patterning on their dorsal surfaces. They cannot be mistaken for the much stockier and stipple backed Skwalas, who's tails and antenna are also more than twice as long.

Because of this confusion over nomenclature maybe reports by anglers of "Skwalas" from other regions of the West that are described as strongly olivaceous in color are in fact referring to Chloroperlids and not Perlodids? This needs to be sorted out.

Lovers of large cobble bottomed riffles and runs, their behavior is consistent with other large stoneflies except that they are more prone to floating long distances as they placidly oviposit... And with the exception of the pteronarcids (Salmon Fly) in some locations, they do it in larger numbers. There is usually no challenge to them for the fishes attention until the March Browns (Rhithrogena morrisoni) begin to appear a few weeks later. Their flights occur during the warmest part of the day which usually means in the afternoons. I have also fished over impressive flights around the lunch hour. They finish well before dark.

The female nymphs run approx. 22 mm in body length with tails and antenna as long as their bodies. The males are substantially smaller. In build and markings, they superficially resemble the larger Perlids (Golden Stones), but are less stout and colored a bit differently with greater contrast between ventral and dorsal surfaces. The large perlid nymphs tend to be dark patterned amber (oak turkey wing) dorsally over pale amber ventrals; Skwala nymphs are even darker patterned brown (turkey tail) over primrose.

The adults have smoky brown wings, brown legs, and primrose abdomens ribbed with brown or the reverse. The males are brachypterous (very short winged). Their curiously marked sternites are perfectly matched by the yellow/black variegated chenille when its wrapped on a hook (to bad it doesn't float well). Gravid females carry black, pea shaped egg clusters off the tips of their abdomens that are larger in diameter than their abdomens. Folding a section of black foam to stick out beyond the hook bend is a wise addition to some of your dry imitations in case you find fish attracted to the those that have yet to drop their eggs.

Unfortunately, another trait they share with other large stonefly genera is their propensity for cyclic population densities. Frankly, many of the western large stonefly genera appear to be in a down cycle from their peaks of a few years ago in a lot of locations, and their present populations on some of the rivers I fish are nothing like the "blizzards" we saw in the 70's.








"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
SayfuOctober 31st, 2011, 7:18 pm
Posts: 560
Entomen, Probably not the place to address it, but in looking at the sites description of stoneflies, I read, "without acception, they emerge by crawling out of the water." I do not believe that to be true. I believe it is some perlodidae...some yellow sallies, that emerge out in the water. I believe I have witnessed that phenomena.
EntomanOctober 31st, 2011, 7:46 pm
Northern CA & ID

Posts: 2604
Sayfu,

That's my experience as well... They definitely do. The same phenomena has also been reported by reputable sources for the big perlids on rivers like the Umpqua, though I've never witnessed it personally. I am working with Jason on updating the stonefly pages with western info and we'll get it done as soon as possible.

Best regards,

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
CutbowNovember 1st, 2011, 11:29 am
Post Falls, Idaho

Posts: 38
I just want to say how good of a post this is and I agree with the observations. I have also percieved a down cycle of large stoneflies in my neck of the woods this year. Also as a side note I have observed some species of mayflies that can hatch by either crawling out of the water or on the surface of water, namely the Gray Drake.

Another subject: I was out elk hunting last weekend and in the middle of the day my buddy and I stopped over a bridge to watch the trout feed in the river below and we saw (no kidding) hundreds of trout packed into a pool feeding on what looked to be small beatids. We soon forgot about chasing Wapati for a while and enjoyed the wonderfull entertainment while cussing ourselves for not bringing our flyrods along. I know Entoman will be dissapointed in his nephew for admitting that I was unarmed for trout on such a wonderfull day but I have to come clean. :)

Anyway, thanks for a contributive read!
"Once you catch your first fish on a fly you won't care about any other kind of fishing!"
EntomanNovember 1st, 2011, 3:06 pm
Northern CA & ID

Posts: 2604
Hi John,

Ha! Don't you love it? I've done that a time or two chasing ducks in years past... One morning was the best baetis hatch I've ever seen. The river was alive with rising fish. By the time I got back to the cabin to fetch a rod it wound down. Those little olive quills will do it to you every time... Moral? When you're hunting, don't go near the water! :)

"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
OldredbarnNovember 1st, 2011, 3:38 pm
Novi, MI

Posts: 2599
Those little olive quills will do it to you every time...


Mother nature's little gift to try and keep us humble...;)

A good friend of mine told me a story of an evening he and some friends had years back...They had been out at the bar doing some serious lifting and were all driving back to the cabin...They drove over the bridge over the Au Sable...They got out and looked over the edge to see what appeared to be every fish in the river feeding in the middle of the night...Brown Drakes!

Imagine...They went running for the waders and rods, tripping over each other...It was lucky that one of them didn't drown...What is that old saying about, "God watching out for children and drunks!?" :)

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
GutcutterNovember 1st, 2011, 10:09 pm
Pennsylvania

Posts: 470

Ha! Don't you love it? I've done that a time or two chasing ducks in years past... One morning was the best baetis hatch I've ever seen. The river was alive with rising fish. By the time I got back to the cabin to fetch a rod it wound down. Those little olive quills will do it to you every time... Moral? When you're hunting, don't go near the water! :)


Or the reverse situation. How about chasing October caddis or November baetis and finding no bugs or no rising fish and spooking a small flock of mallards or blacks or widgeon at each bend of the river!
AAAHHH!!!
All men who fish may in turn be divided into two parts: those who fish for trout and those who don't. Trout fishermen are a race apart: they are a dedicated crew- indolent, improvident, and quietly mad.

-Robert Traver, Trout Madness
OldredbarnNovember 1st, 2011, 10:31 pm
Novi, MI

Posts: 2599
I can relate, boys...Sort of like making it all the way to the Stanley Cup Finals and losing to the Pittsburgh Penquins...:)
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
EntomanNovember 1st, 2011, 10:58 pm
Northern CA & ID

Posts: 2604
Tony -

Or the reverse situation. How about chasing October caddis or November baetis and finding no bugs or no rising fish and spooking a small flock of mallards or blacks or widgeon at each bend of the river!
AAAHHH!!!

:):)lol - That's what happened the day before! That's why I had a gun in the boat instead of a rod. Ducks everywhere, no gun, no baetids & fish one day - baetids & fish everywhere, no rod, no ducks the next. Nature can be cruel...

Regards,

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
SayfuNovember 2nd, 2011, 9:39 am
Posts: 560
That's a perfect reason to learn to cast left handed if you are a righty. I can only shoot right handed because of this lousy dominant eye that I now have. Cast and blast...great time of year. But it never has worked out for me...only at the chalkboard.

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