"The last thing you change is your fly" The great Lee Wulff
One cannot go to a river like the EB or the Millers during late August to early October and not see them. Large, long, dark forms clinging to stream side stones will greet the angler during his early morning fishing. This is the exoskeleton of the of the Isonychia nymph, one of the largest mayflies around and an insect that emergers all Summer long but especially in the late Summer and Fall.
This mayfly takes it's cue from the stonefly when it comes to hatching and that is the habit of crawling or swimming to shore and then climbing a rock to hatch leaving the shell behind. This act is usually done under the cover of darkness (they would be easy pickings for shore birds if they hatched during bankers hours) although I've seen them at dusk on cloudy days. Needless to say, the nymph is what's important to us instead of the dun.
These are the fastest swimmers in the mayfly family and seem to like to dart around especially at hatch time. Thomas Ames, Jr., in his book Hatch Guide for New England has a number of nymph presentations but I have found that a possum nymph colored black with a sharpie captures form and color. All you have to do is present it correctly. This swimmer doesn't get lost in the drift but swims and darts around. Make it dart around! This nymph is bigger than the Hendrickson. This bug is also a good indicator or clean, well-oxygenated water. Keep a supply ready this Fall.
This weekend - Let's hope for a little rain to freshen up our freestones. The EB has been great this week and I've heard good reports about the Millers and not from the usual places like Orcutt. Seems like the "regulars" are spreading out and that's a very good thing!!
Ken

