Mayfly I.D

Discussion in 'Fly Fishing Entomology' started by Brandon4455, May 11, 2014.

  1. Brandon4455

    Brandon4455 Bobber Down!

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    Hey guys, so in the spring every year on a coast range trout stream here in oregon, these larger brown mayflies hatch. the hatch lasts from opening day (end of april) until the end of may. These bugs are a brilliant rusty brown, with VERY long tails. the bugs are a full size 12 and can be seen all flying around in groups above the river. I was thinking march browns but to me they just seem too large, and the hatch lasts later.



    here are the best 2 photos i have of the insect Opening day 2014 033.jpg Opening day 2014 031.jpg Opening day 2014 031.jpg
     
    GAT and Teenage Entomologist like this.
  2. Teenage Entomologist

    Teenage Entomologist Gotta love the pteronarcys.

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    I'd say a larger species of March Browns( They get big here in California). Isonychia look a lot like that, but they hatch in the fall.
     
  3. Taxon

    Taxon Moderator Staff Member

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    Brandon-

    At what approximate elevation in the in the Oregon Cascades have you encountered this emergence?
     
  4. Teenage Entomologist

    Teenage Entomologist Gotta love the pteronarcys.

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    True, March Browns can live in very high elevations, more so than many other mayfly species.
     
  5. GAT

    GAT Dumbfounded

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    The MBs I've seen on Mac and Willy start out quite large than as the year goes by, the bugs hatching are smaller but still the same critter. I know they're MBs because I frequently fish with an entomologist.

    I've seen the larger MBs in the coast range and I'm pretty sure that's what is shown in the photos. At least, they sure look like the ones in The Valley. Dark back, light underbelly.

    Roger, the altitude of the coastal rivers where Brandon is fishing is probably 400 feet at the most. I have found MBs later in the year at higher elevations in the Oregon Cascades. It seems the hatch starts at the lower elevation and then moves up over time. At least, that's been my experience.
     
  6. Brandon4455

    Brandon4455 Bobber Down!

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    gene you are spot on, the elevation being only between 2-500 ft depending on the section of river. this time of year i only see them high up in the river system but around opening day they are swarming the middle and lower portion of the river.



    -Brandon
     
  7. Alex MacDonald

    Alex MacDonald Dr. of Doomology

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    Yes, I'd have to go with a March Brown too.
     

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