The Mother's Day Caddis Hatch

[Al Agnew]

So I've been in Montana since early spring (early spring by Missouri standards).  It's been for the most part a cold, wet spring out here, with lots of wind.  We are building a new patio and deck, so between the crappy weather and trying to line up contractors, my fishing time has been severely limited. But the highlight of the spring on the Yellowstone is the Mother's Day caddis hatch--if you can catch it right--and I've been hoping for it to happen.

Last week it almost happened.  We finally got three warm days in a row.  Problem was, one of them was TOO warm.  You see, the hatch requires the water to warm to a certain temperature, like up close to 50 degrees, before the bugs metamorphose.  But if the weather gets too warm too quickly, it starts the higher altitude snowmelt.  Which blows the river out.  So there is more than a 50/50 chance in any given year that by the time the bugs appear, the river is chocolate milk.  So last week, the caddis started happening on the second day of warm weather, and got pretty thick on the third day, the hottest day at over 80 degrees.  And then the bottom dropped out of the temperature gauge...next day it was 35 degrees and snowing.  The bugs, of course, shut completely off, and that day the river also started rising; it takes a couple days for the rise to get from Yellowstone Park to Livingston.  It quickly rose more than 2 feet and got muddy.  But the cold also stopped the snowmelt.  So I was hoping the river would drop and some moderately warm weather would happen this week.  It did.  From a high of over 8000 cfs, it dropped below 4000 yesterday, and further dropped today.  The last two days before today had temps in the high 50s, and today it went up to the high 60s.  And that was enough to get the hatch going.

Mary and I had to do some stuff the morning, but we finished at noon, ate lunch, and then got ready to get on the river.  The bugs were flying around at the house, not only caddis but some nice brown drake mayflies.  I watched the river a bit but didn't see anything rising.  So I wondered if the bugs were going to be thicker upstream--the hatch always seems to move upstream.  So I called the shuttle service and arranged a shuttle from Pine Creek to Carter's Bridge.

At the put-in, there were caddis.  On the banks near water's edge, they were thick enough that there would be about 20 per square foot.  The air had about one per square foot, and there were a few floating on the water.  But nothing was feeding on the surface.   Floating with Mary in the little drift boat, I have to do the rowing (she wants to learn to row but a shoulder replacement and some arthritis in the other shoulder makes it tough for her), so the only way I can fish is to stop and wade, or anchor the boat.  We stopped at the first likely riffle eddy, and I tried nymphs with no luck.  So we continued downriver, looking for rises.  The bugs were getting thicker.  We reached a long, rip rapped wall (it separates the river from the spring that forms the famous Nelson's Spring Creek), and it seemed the caddis were thickest along the rip rap.  In a small eddy I saw a few fish rising.  So I anchored the boat a cast length downstream along the bank and tried for those fish.  I was using a caddis imitation that was fairly realistic and a match for these bugs, which are about 5/8ths of an inch long.  Problem was, the bugs were getting thicker, and I simply couldn't see my fly in among the real critters.  I struck a couple times where I saw a rise where I thought my fly was, but no luck, it was a real bug taker.

And suddenly, as if by magic, the hatch really took off.  It's hard to describe.  From a bug every 6 inches or so on the water, now there was less than an inch between bugs.  They congregated in the slick water between the swirls and wavelets in carpets, some of them 3 feet wide by 6 feet long completely covered in bugs.  They were clustering together in little clumps of a dozen of so in a ball...we've called these "caddis cookies" in past hatches.  Now I knew it was impossible to fish a fly that perfectly matched the real thing...you coudn't see it, and what were the odds of the fish taking your imitation in among hundreds of real bugs within its feeding station?  So I switched.  I dug out an Elk Hair Caddis at least two or three sizes bigger than the real bugs.  It was also lighter in color than the real ones.  So it was easy to see.  And I suspect it imitated those clumps of caddis.  Trout are opportunists, too.  If one can gulp down 6 caddis at once, why not?  At any rate, it worked.  I'd pick a spot, anchor, cast to an eddy where fish were rising, and usually get a take or two.  But really there still weren't that many fish rising.  So we kept moving for the most part, watching for signs that the fish were really turning on.

Well, the hatch began to thin about 4 PM, and THAT's when I saw the fish turn on.  Now they were picking out individual caddis instead of the clumps.  As we were drifting down the main channel, I saw constant, multiple rises in a smaller channel just off the main river, separated from it only by a thin spit of a bar.  The side channel was still good sized, it wouldn't be easy to wade across at the riffles.  There was a nice run, tailing out in a wide, shallow riffle, and fish were rising constantly.  So we stopped.  In a stretch about 50 yards long above that riffle, there must have been at least 40 fish rising, all over the channel.  I walked quietly up along the edge to where it looked like some bigger fish were coming up and gave it a shot.  The first fish I drifted over took, and it was a nice rainbow, about 15 inches.  Alright!  I'd been a little afraid that most of the fish were whitefish.  So for the next two hours, I fished that 50 yard stretch.  A good portion of the fish WERE whitefish, and while whitefish take dry flies well, they are more difficult to hook because of their small, underslung mouths.  But I'd say that about every third or fourth cast, on average, I'd get a take.  I didn't keep track of how many I caught...maybe 15 trout and 20 or so whitefish.  At one point, I got at least a dozen takes in a row and never hooked a fish...and then I checked my fly and I'd been fishing without a hook!  I was slowly working my way down to the shallow tail-out above the riffle, and was thinking that surely it was all whitefish there, when I got a take at the end of a long drift downstream and a big rainbow leapt three feet out of the water.  It would have been the biggest of the day, probably 18-19 inches, but it got off as I got it close.

It was now 6 PM, and time to head in.  I left that spot with fish still rising, and rowed the last mile to the take-out.

So tomorrow I've got the afternoon free, and the weather is supposed to be like today was.  I'm going to take the little Water Master and probably do the same float.  If the hatch occurs like it did today, I'll take some pictures of it...you have to see it to believe it.

[fishinwrench]

Good stuff.  Sounds like a blast.  

[Al Agnew]

Well, the bugs weren't as thick today.  I thought I could just drift the elk hair caddis along the banks as I floated downstream in the little raft, but only caught a couple trout doing that.  The hatch exploded for about 15 minutes, and I caught a few during that time.  Other than that, I'd find occasional pockets of fish rising, but it was only when a cloud would cover the sun.  As soon as the sun popped out again, the fish stopped rising.  And there weren't all that many clouds.  So I'd only caught about a half dozen by the time I got to the spot I'd caught the most yesterday.  There was nothing rising; the sun was out full blast.  It was also a little windy.  When the wind would die down a bit, the bugs would get thicker.  I figured that in about a half hour the sun would go behind a mountain; it was nigh on to 5 PM.  Maybe then the fish would start rising.  So I ate a snack, drank a Coke, and waited.  Finally, the sun slipped behind the mountain.  The shadow came from downstream, and as it reached my tail-out, the fish started rising.  I had told Mary to plan on picking me up at 6 PM, and it was after 5:30.  I called her and told her not to expect me for a while yet.  And proceeding to have a complete blast.  Mary asked me how many fish I caught, and I had no idea, but it was a bunch.  Biggest was an 18 inch rainbow, and couple others 16-17 inches, but most were 12-14 inches.  But when you have that kind of dry fly fishing, I don't really care that the fish are small.  If I got a drift right in the feeding lane of a rising fish, it would take.  There were enough bugs on the water that they didn't need to move sideways to eat, so you did really have to drift right through their feeding lane, probably no more than a foot wide.  

I ended up calling Mary to pick me up at 7:30!

Too tired to get the pictures off my phone, didn't take any of the fish, but took a lot of bug pictures.  Will post a few tomorrow.

 

 

 

[Al Agnew]

Here are the bugs on the water just starting to get thick.  But this concentration only lasted a few minutes yesterday.This was a rock at the edge of the water, covered in caddis.  The mass just under the surface is their eggs, which are not much bigger than a pinhead when laid, and lime green.  They stick to everthing and quickly swell up and dull in color to match the rocks better.And this is what this section of river looks like.  Iconic Paradise Valley!