One of best hatches on the Au Sable River and most of our top trout streamers in Northern Michigan. This hatch starts right about now depending on weather and will last all the way till end of summer. Heaviest numbers are in June. Often over shadowed by our hex hatch but its typically the pre game before the hex get going after dark.
Here is photos of a Iso dun and nymph that I took on the Au Sable. Was looking for pic spinner but I couldn’t find one which is surprising because always taking photos of river bugs. Spinner has maroon body (reason some call it a maroon drake), white legs and clear wing. Look for hatches to start in the evening and spinners in the late evening. Most love this bug because you can see! During major heat the Iso hatch and spinner fall can be after dark.
Iso’s love the riffles and that is where they hatch from in the biggest numbers. The nymph can swim! To catch them you need to flip small rocks and like hunting crayfish. Fishing Iso nymphs is very productive. On a floating line with long leader or as trailer behind a small streamer with a sink tip. Need to move these nymphs with strips and twitches. Trout love chasing them right up to the surface. Have good luck stripping an over sized swimming nymph. This nymph is ideal for a dropper below a stone fly this time of year. Keep moving that stone on the surface. Dropper below a crayfish pattern is also very effective.
Here is are some of our most popular patterns for this hatch:
I do have all of these for sale in our online sales plus a lot more: https://michigan-streamside.com/product-category/flies/dry-flies/big-mayflies/
