Killer hatch... almost literally (merged)

[pcray1231]

No,

I was saying that all the bugs here that I see have 2 tails, not 3.

"Dark Green Drakes" (litobrancha recurvata) also have 2 tails, but hatch before the green drakes do, so I'm calling that unlikely. I know there was some hoopla about these bugs this year on Clark's Creek.

Brown drakes (ephemera simulans) hatch afterwards, but have 3 tails. These bugs have 2 tails. So they aren't brown drakes. Unless you saw a pic that I'm not seeing? (it is possible to have multiple bugs in the swarm)

Hence, these large mayflies are hatching in June, and they have 2 tails. They must be hexagenia.

As for exact species, probably hexagenia limbata as the timing is right and they are known to hatch on larger rivers in swarms like this, for instance on the Allegheny, and shut down bridges and such the same way. If they are new on the Susquehanna, well, congrats, but I bet this happens every year from now on out. They've been on the Allegheny where I grew up as long as I can remember, but I do recall around 2001 or so they started showing up in the city itself, which was "new" to the city folk, and caused a bit of a stir.

Possibly hexagenia bilineata. They look similar and can come off in equally impressive numbers, but in my experiences tend to happen in July. Whether timing would be the same on the Susquehanna I dunno, hence my uncertainty. You could make the argument that SC PA, in terms of hatches and other springtime natural cycles (like leaves, blooming, etc.), tends to be 2 weeks ahead of western PA. Hence limbata should be done and it's about the right time for bilineata.

Your hex hatch around the white fly time is probably hexagenia atrocaudata (aka the "Late Hex"). Same genus. Different species. I have not personally witnessed this hatch in any decent numbers, but have been told secondhand of largish hatches, for instance on Slippery Rock Creek.

"Hex" is not a single bug, it is a genus consisting of multiple bugs. Kinda like ephemera is a "drake" but there are green drakes, yellow drakes, brown drakes, etc. within that genus. (and the "dark green drakes" are actually much more closely related to hex's than drakes)

 

[krayfish2]

Ok. Misread your first post and did take a second look at the bug. Eric from Boiling Springs could confirm the exact insect as he studies aquatic insects for the state.

I agree hex but the hatch is reminiscent of the blizzards seen on the great lakes and not what we'd expect here. I'm using 'hex' to describe the bug just as I'd use 'steno' to cover any number of hatches under that family of bugs. At any rate, theres literally tons of them sittin on the bridge. Very cool yet creepy sight.

 

[pcray1231]

Well, blizzards like that have been happening for some time on the bigger rivers in the western side of the state. But they had been "expanding", seemingly in large jumps as they approached the city.

Do areas farther north on the Susquehanna historically have such hatches?

It's a good sign. Means the river is getting cleaner. Now, whatever was holding the bug pops down may not be the same thing that affects the bass. But it's certainly not a bad sign....

It does seem like all kinds of hex's are becoming increasingly common in PA. Wonder why that is?

 

[FarmerDave]

I've seen one of those blizzards on Lake Erie. I'm a half hour drive from the lake so I don't get any here, but one year I was out by Sandusky during a hatch (the city of course) and it was quite impressive.

Apparently they started about a week ago out near Toledo.

Those are hex, right?

 

[krayfish2]

If I'm not mistaken, read stories of snow plows being used to clear bridges around williamsport in the past. I believe those were white fly hatches though

 

[wgmiller]

This was on my car in Columbia (next to the Burger King) one morning when I got dropped off by my carpooler. It did have two tails, you just can't see them very well in the pic. July, 2011...

 

[pcray1231]

Those are hex, right?

yeah. And the species dominance has been a major source of study. Erie was pretty barren of mayfly life prior to the 90's, due to pollution. In the early 90's as the lake cleaned up hex's took over. First, hexagenia rigida, I believe, which dwells in lakes only, not moving water. Then limbata and bilineata have taken over the deeper areas, but rigida still found primarily near shore.

Interesting that it was in the late 90's when limbata started taking over the lake, and the same time period where they started to colonize the Allegheny, starting north and moving south every year till they got to Pittsburgh and now down into the Ohio (not sure about the Mon, anyone know?). Around the same time, hexagenia rigida colonized Pymatuming.

And while the "late hex's" (atrocaudata) were always here, they are a more spread out hatch, I believe, and don't form the epic swarms, and get outshined by the white flies. It seems the earlier, swarming types (bilineata or limbata) have now made the jump over to the Susquehanna drainage.

Makes me wonder if the cleaning up of Lake Erie was the impetus for all of this. These hatches have always been epic, as we know, in the upper Midwest, like in Wisconsin/Michigan/Minnesota. Heck, it's downright legend on the Ausable in Michigan, and the upper Mississippi is where they track them on radar and bass fishermen follow (or avoid) them. But the lower Ohio was too polluted to really move up. But Erie makes a fine vector to get to the cleaner portions of the Ohio drainage...

And further, I wonder what happens if they overlap with our green drakes?

I started trying to learn about them prior to being a fly fisherman. When I was in HS, bridges around home had to be shut down with plows to clear them. And they were "new" then. Then they discovered "hey, we know when this happens, why not just shut out the lights?" lol. You knew it was hex times when you'd go through a town at night and it was dark. But some event would always get "shocked" by them. I remember a rodeo on the banks of the Allegheny, under the lights. That went well, lol. The lights were hot and killed the poor things, then they fell dead. The bleachers were EMPTY of people and piled high with bugs. They show up at Pirate games, but the stadium engineers purposely chose lights that apparantly do not attract them as much, or maybe just don't kill em, I dunno. There's still enough fluttering around to make everyone talk about em, and some poor souls squeal in disgust. But not enough to form piles underneath.

I'd note that in NW PA, smaller trout streams got them as well. Not in quite as epic of numbers, but they're there and create a very fishable hatch. Timing is poor as it's mid-summer and trout fishing is generally relegated to smaller waters.

 

[dc410]

Here is another photo I took yesterday afternoon of the clusters of mayflies hanging on the riverside vegetation. The photo is a bit dark but they can be seen fairly clearly on the dead limbs. This photo was taken at about 2:50 PM and as the afternoon wore on more and more mayflies came out of the trees in swarms. I didn't do a whole lot of fishing - I was mainly watching the bug show and trying to get some photos of it.

pcray - most of the Limbata hex flies that I ever saw in June were a lot lighter in color like the one in Geo's photo above. These were very dark which is what had me a bit confused but I guess there can be drastic color differences within the same species at different locations, right?

 

[pcray1231]

Yeah, there can be.

Also, bilineata is a lot darker species. I hold that this is a possibility.

And also note, significant color differences between dun and spinners, with spinners being darker. Post #27 clearly shows a dun of whatever it is.

 

[troutbert]

dc410 wrote:
Here is another photo I took yesterday afternoon of the clusters of mayflies hanging on the riverside vegetation. The photo is a bit dark but they can be seen fairly clearly on the dead limbs. This photo was taken at about 2:50 PM and as the afternoon wore on more and more mayflies came out of the trees in swarms. I didn't do a whole lot of fishing - I was mainly watching the bug show and trying to get some photos of it.

dc410, those photos you posted of the bugs on the trees are amazing.

Have you fished Lake Aldred much in past years around this time? Ever see anything like this before? Or hear others talking about this in past years?

I wonder if this is mainly a Lake Aldred thing. The bridge crosses the river just where it flows into the upper end of Lake Aldred.

It may be that the fine sediments accumulated in the impoundment provide habitat that supports vast numbers of Hexes.

But most of the Susque is riffly, so has a lot of coarse substrate (cobble and gravel), so probably will never support huge numbers of Hexes like shown in the photos.

 

[pcray1231]

troutbert,

Certainly true that impoundments accumulate silt, and more silt results in more hexes in that vicinity.

But in regards to the bridge itself being a beacon, I wouldn't look past the new lights that were installed last summer (based on the article comments section). Different lighting attracts them in different degrees. And if this goes beyond a gross out factor and is seen as a real public safety concern, then those lights are probably the first thing to look at. I think simple cellophane like coverings to shield certain wavelengths are effective.

That doesn't splain the trees. But unless it's a new dam or something, I have trouble buying that it suddenly just accumulated enough silt. So whether it's happened before is a good question. And if it hasn't, well, hex populations do seem to be expanding throughout the state.

 

[Maurice]

Yes it is ALL about the lights. Just turn them out during hatches for crying out loud...This whole thing is so stupid. Shut down the bridge when a light switch would stop them from congregating there. They are not shutting down the Rout 30 bridge 1/4 mile up river...

Whats different?

What changed?

After they installed the lights last year they had to turn them off during the white fly hatch I think. Why not this time?

There may be more bugs, maybe not. But there ARE more lights. and Light attracts bugs. Don't try to figure out what wavelength is the best, flip the switch...all those years before there were no lights. Now there are. Even though the lights were lit all year, this is the first we've had the problem. What changed? The Hexes hatched...So Turn out the lights when the hatch is on.

Its simple really.

 

[troutbert]

pcray1231 wrote:

But unless it's a new dam or something, I have trouble buying that it suddenly just accumulated enough silt.

That is not my theory, which is about the LOCATION of the mega hatch.

Not about the TIMING of when the mega hatch began.

As I said, I think it is likely that this mega hatch is occurring only in the impoundment, because of the fine sediment there.

And that you would not find a comparable mega hatch anywhere in the free flowing section of the Susque, because most of the sediments are coarser.

For those who live near and/or fish the river regularly, let us know what you see, it's all very interesting.

 

[FarmerDave]

Mo, it likely boils down to what some group of lawyers decided is the best way to avoid law suits. Which is likely to reduce the number of accidents, turn off the lights or shut down the bridge?

On the other hand, the answer is not a simple one unless the lawyers are simple minded.

No offense intended to lawyers in general.

 

[wgmiller]

Sediment collecting behind the dams has been occurring for years. The "mega hatch" isn't likely due to anything changing there...

Perhaps the Miracle Gro chemicals from the Miller Chemical fire "fertilized" them :-D :-D

All kidding aside, it could have just been a "perfect storm" of air temps, sun, water temps, etc.

 

[JackM]

... plus the lawyers, can't forget them.

 

[wgmiller]

http://www.troutnut.com/hatch/32/mayfly-hexagenia-limbata-hex

"Current Speed: Slow streams or stillwater.

Substrate: Silt beds of just the right consistency, soft enough to easily burrow into but strong enough that they don't collapse

Environmental Tolerance: They survive in warm water but thrive in cold. They are very durable once they've grown large."

I'd say the water south of the Rt. 30 bridge down to the Safe Harbor dam certainly provides good habitat for them.

 

[troutbert]

wgmiller wrote:
Sediment collecting behind the dams has been occurring for years. The "mega hatch" isn't likely due to anything changing there...

The Hex mega hatch may have been there (Lake Aldred) for many years. The mega hatch may not be a new event at all.

But only became widely known after they put the new, low lights on the bridge, causing all those problems, making it a news story. (What Maurice said.)

The big whitefly hatch is well known to fishermen because it occurs over pretty much the entire length of the river.

This Hex mega hatch could have been occurring for a long time, but never was widely known to most fishermen, because it only occurred at one specific location, at Lake Aldred, not all along the river.

 

[IdratherbePhishing]

Was told by a local that it was bad again last night.

 

[Swattie87]

Found 2 Hexes on my car last night in the Walmart parking lot in Morgantown, PA. Extreme headwaters of the Conestoga drainage. FWIW.