Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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Keystoner on May 3, 2011May 3rd, 2011, 4:29 am EDT
So there I was, fishing the Jordan Creek early this AM. Started at about 5:30, and right from the start there was a lot of surface activity. Rises pretty much everywhere, and a few fish leaping out of the water.
I am wondering what this hatch could have been. To provide some info, the Jordan is a freestone stream that spends most of it's late summers completely dry. Therefore all trout in it now are stocked. Also, all the fish I did catch where taken on a Hunchback Pheasant Tail 16.
Thanks for any input.
I am wondering what this hatch could have been. To provide some info, the Jordan is a freestone stream that spends most of it's late summers completely dry. Therefore all trout in it now are stocked. Also, all the fish I did catch where taken on a Hunchback Pheasant Tail 16.
Thanks for any input.
"Out into the cool of the evening, strolls the Pretender. He knows that all his hopes and dreams, begin and end there." -JB
Troutnut on May 3, 2011May 3rd, 2011, 8:15 am EDT
I can't say for sure since I don't know that stream, but a midge hatch is always the likely culprit when trout are rising all over the place to some tiny unseen thing.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Troutnut and salmonid ecologist
Jesse on May 3, 2011May 3rd, 2011, 10:53 am EDT
I agree with Jason its more than likely a variety of midge's hatching off. Gots to be!!!
Most of us fish our whole lives..not knowing its not the fish that we are after.
http://www.filingoflyfishing.com
http://www.filingoflyfishing.com
Oldredbarn on May 3, 2011May 3rd, 2011, 12:05 pm EDT
Matt,
I'm going to be the contrarian here...It's my nature I guess...
Nowhere in your post did you state that you were unable to see what was the cause of this activity...Your post is shy of observational information...Did you see any bugs what-so-ever?
I think a size 16 PT is almost always a good choice when you may not know what's happening...It's a good place to start anyway.
My guesses are as follows in what I think may be the order of probability with my first choice #1...
#2...I just got back from Grayling and they are a little behind, hatchwise, for this time of year...I spotted one small black caddis...There are a few different suspects that should be around now or at least soon.
#3...Some of the little early spring stones have been hanging around for a while already and I saw a few different species with a size 18 being the most interesting to me since it's been a while since I've made it up for opening day...They come in a variety of sizes here and I had them crawling all over me...Some crawl towards the shore to emerge and some ride for some time on the current and seem to hardly move until they want to fly off. I have seen small brookies leave the water and intercept them as they ride along...It almost looks like they are playing and they take them on their way back in to the water...You would have a difficult time seeing them since they are basically flat & dark as they ride along...
The caddis mentioned above can cause splashy rises as they rocket to the surface with a hungry trout in hot pursuit...They seem unaware that there is an end to their environment and can also leave the water...
The Paraleps are pretty good swimers and could cause something similar to a trout chasing a caddis up...A size 16 would be in the ballpark for them and even a Henny for an indiscriminate stocky...
My guesses...
I had a nice hatch last Saturday and it was interesting because most of the fish needed to find calmer water since the river was at flood stage. I sat there and watched as the Hendrickson's were flooding off with the Baetis & Mahoganies blended in...We caught fish on top but not all of them. I pointed out to my angling friend that some of the surface activity was caused as the fish caught a dun on the way up and turned back down to its feeding station...This caused a surface bulge...
My $2.50 cents worth...I know you were out early, but I'm not so sure this matters...When you got to go, you go!The weather over here has been weird enough to hamper what might be considered normal, though the Hennies were like clockwork...I looked like a genius when I kept joking, "Hennies at 2:00...Better be in your spot by 2:00." It was like I had them trained. :)
Spence
I'm going to be the contrarian here...It's my nature I guess...
Nowhere in your post did you state that you were unable to see what was the cause of this activity...Your post is shy of observational information...Did you see any bugs what-so-ever?
I think a size 16 PT is almost always a good choice when you may not know what's happening...It's a good place to start anyway.
My guesses are as follows in what I think may be the order of probability with my first choice #1...
Although classified as crawlers, Paraleptophlebia nymphs swim very well. They are generally tolerant of faster water than Leptophlebia and inhabit pockets in riffles as well as moderate runs.
#2...I just got back from Grayling and they are a little behind, hatchwise, for this time of year...I spotted one small black caddis...There are a few different suspects that should be around now or at least soon.
#3...Some of the little early spring stones have been hanging around for a while already and I saw a few different species with a size 18 being the most interesting to me since it's been a while since I've made it up for opening day...They come in a variety of sizes here and I had them crawling all over me...Some crawl towards the shore to emerge and some ride for some time on the current and seem to hardly move until they want to fly off. I have seen small brookies leave the water and intercept them as they ride along...It almost looks like they are playing and they take them on their way back in to the water...You would have a difficult time seeing them since they are basically flat & dark as they ride along...
The caddis mentioned above can cause splashy rises as they rocket to the surface with a hungry trout in hot pursuit...They seem unaware that there is an end to their environment and can also leave the water...
The Paraleps are pretty good swimers and could cause something similar to a trout chasing a caddis up...A size 16 would be in the ballpark for them and even a Henny for an indiscriminate stocky...
My guesses...
I had a nice hatch last Saturday and it was interesting because most of the fish needed to find calmer water since the river was at flood stage. I sat there and watched as the Hendrickson's were flooding off with the Baetis & Mahoganies blended in...We caught fish on top but not all of them. I pointed out to my angling friend that some of the surface activity was caused as the fish caught a dun on the way up and turned back down to its feeding station...This caused a surface bulge...
My $2.50 cents worth...I know you were out early, but I'm not so sure this matters...When you got to go, you go!The weather over here has been weird enough to hamper what might be considered normal, though the Hennies were like clockwork...I looked like a genius when I kept joking, "Hennies at 2:00...Better be in your spot by 2:00." It was like I had them trained. :)
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
"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
Troutnut on May 3, 2011May 3rd, 2011, 1:04 pm EDT
Spence is right, it could still be a lot of things based on the information you gave us. Midges are my first rough guess, caddis my second, but there are many options.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Troutnut and salmonid ecologist
Keystoner on May 3, 2011May 3rd, 2011, 2:12 pm EDT
Hmm, thanks guys. To divulge a bit more, I did not see any insect activty whatsoever. Usually if it's BWOs, Caddis, or Stones I'll see at least a few in the air, or, on my person. But this morning, nothing. I had myself considered midges, however, I was hesitant to make the change as they where hitting the PT16 very nicely.
My hope, is that I haven't missed all the action and will find the same thing tomorrow AM. Thus, allowing me to experiment a little.
I will certainly report back, post session. Thanks again.
As a side note, I often wonder if the stockies see the Pheasant Tail for what it is supposed to imitate, or if they just see a brown thing and think, "pellet!"
My hope, is that I haven't missed all the action and will find the same thing tomorrow AM. Thus, allowing me to experiment a little.
I will certainly report back, post session. Thanks again.
As a side note, I often wonder if the stockies see the Pheasant Tail for what it is supposed to imitate, or if they just see a brown thing and think, "pellet!"
"Out into the cool of the evening, strolls the Pretender. He knows that all his hopes and dreams, begin and end there." -JB
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