Friday, April 15, 2011

Stream Report: Powells Creek near Crozet

Our rivers continue to run very high after heavy rains on Tuesday.  And with more rain expected tomorrow, I thought I'd better get out today to see what I could find. I've had to to stick to small streams this week-- so I thought I'd go back to the Powells.  The water was high and fast here as well: still, I was able to find lots of insects without looking real hard.

The Powells at the moment is loaded with Perlodid stoneflies, genus Isoperla (as in the photo above).
I knew that, and one of my goals today was to get a really good photo of that genus of nymph.  I'd call this one "so-so".  I always want all parts of the nymph in really sharp focus.  I'll have to return and try again early in May.  (Note:  I'm still not sure of the species of this Isoperla.  The photos look very much like Isoperla montana, but it's not safe to rely on photos alone.)

Lots of stoneflies again in the leaf packs.  Literally dozens of Isoperlas in one big pack of leaves -- but I also found Eccoptura Common stoneflies, a few Diploperla Perlodids (fully mature wingpads -- ready to hatch), and a couple of tiny Nemourids (genus Amphinemura).  This genus of Nemourid is tiny to begin with, and when they're still in early instars, they're very difficult to shoot with the camera, even with a good macro lens at full magnification.  Here's the best I could do.  (Don't forget to click on all photos to enlarge them for better viewing.)

At least this one was big enough to allow us to make out the "cervical gills" at the neck.

Mayflies?  I saw a few flatheaded mayflies, all still Epeorus, and a couple of small spiny crawlers.
That's about all I can report for today.  But let me show you the nice photos I got of the Eccoptura stonefly and the Diploperla Perlodid.

Eccoptura common stonefly (Perlid):

Diploperla Perlodid:

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