Killer hatch... almost literally (merged)



Mar 21, 2009

4 motorcyvcle accisents caused by mayflies?! Anyone see this?

Not to make light of the people who may have been injured but... Do the smallies turn on to whatever is hatching now like they do the white may flies later in summer?
I came across the bridge yesterday at 2:00pm and there wasn't a single bug. I'd think that if there were that many last night there would be remnants from the night before yesterday...i think those pics/article is from last year.

And based on the pic the flys look like white flys that come off in late July.
Bridge closure over the Susky last night. Did not say what kind of mayflies. I would guess light cahills based on time of year.

This news is confounding information about the Susky. Generally, the presence of mayflies in abundance is a sign of good water quality, yet something in that stream is affecting smallies.
What a bunch of ignorant people on that forum! Someone should educate them on beneficial native bugs.
If anyone finds out what kind of mayflies these are, please let us know.

Chaz I agree, there are some very uneducated people making strong statements on that message board. Its actually very amusing.
Here's some images borrowed from Facebook (Tim and Amanda's Freelance Photography):


The "day after" that was sent to me by a friend:

Here is a picture of the mayfly


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Yup. WGAL has a good shot of one as well. Reminds me of a hex...

I was on a pontoon boat this afternoon on Lake Clarke fishing the York County shoreline and the hatch of big mayflies was incredible. Bear in mind that these photos were taken between 2:00 - 3:00 PM this afternoon. I have attached a few photos that I took this afternoon. I am thinking that they are a Hex spp. but I will let it up to the guys that have more experience than me. Some of the piles of the mayflies under the lights on the 462 bridge from last night were about 18' - 24" in height. They definitely had an issue last night on that bridge and may very well be having the same issue tonight. Here are the photos. We did catch and release a few decent smallies this afternoon and they all looked healthy. No photos of the bass as the immediate catch and release regs were being strictly followed.


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Oregon_Owl wrote:
This news is confounding information about the Susky. Generally, the presence of mayflies in abundance is a sign of good water quality, yet something in that stream is affecting smallies.

And not only is the Susky full of mayflies, it also has a lot of stoneflies. The presence of these bugs is a main argument put forth by those who are not in favor of a declaration of impairment. I often point out to friends and casual anglers who frequently tell me the river is "polluted" to pull a rock and check the insects underneath - looks like Penns Creek.

Amazing photos. We usually think of such swarms that cause traffic problems as being associated with white flies that hatch later in summer. I'm not sure I've heard of such quantities of bugs in June.

For you Harrisburg locals: Is this a common thing in June?
Looks like tonight is a repeat of last night (as predicted). Amazing.
It was almost unbelievable yesterday afternoon along the shore of the river. I've never experienced anything like that in the middle of the afternoon. I actually saw and heard several significant sized limbs broken off by the sheer weight of the hanging mayflies. Truly an amazing sight.
The closeups here are all genus Hexagenia. Not 100% sure on species. The Allegheny does this every year. Twice (2 different species). I'm gonna guess Limbata based on timing. The Limbata are June, Bilineata are in July.

Old article of back when this started happening in the city (not nearly as heavy as out of the city, though). These are Limbata. Notice date of article:

And here's one of the bilineata. Again, notice date in the descriptive comment.

Hexagenia atrocaudata is usually then late August, and often coincides with the white flies. Does not seem to be in any "blizzard" swarms in PA that I'm aware of, but there's a few around.
One pick strikes me a a brown drake, one makes me want to say hex. No hatches like that around Dauphin. I have seen lots of stenos and big stones lately.

Let those 3' piles marinade all day in this heat....they'd have to be pretty ripe smelling. P U
These are all over our parking garage & buildings today in Hershey. Not sure if the Swattie is getting the same hatch or if they were blown this way from the Susky. The spiders are feasting on them.

I have photos in my files here on our building of the same mayfly from the first week of July in 2003. Haven't seen them this thick in the past however.


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One pick strikes me a a brown drake

Which one? Easy way to tell is number of tails.

Ephemerella genus has 3 (includes green, brown, and yellow drakes).

Anthopotamus (golden drakes) also have 3.

Hex's have 2.

Hence, when dealing with mayflies of this size, a good rule of thumb is 3 tails = some sort of drake and 2 tails = some sort of hex.

There are 2 exceptions, and neither are technically drakes nor hex's, though the common name does use "drake".

Iso's (aka slate drake). 2 tails.

Litobrancha recurvata (aka dark green drake). 2 tails.

I'm doubting the latter due to timing. They look similar, but typically emerge prior to the regular green drakes, whereas hex's typically come after.
Lost me Pat. Are you telling me that brown drakes hatch before green drakes do? I thought they came right after the green drakes. Also found my first few hex duns on the deck over the last 3-5 days. Where I'm located on Susky has a hex hatch but it's minimal. There is a bit heavier emergence around the time of the white fly. YMMV.