llllill rli
fabfiIfsr,.n",
Isonychia '/
ver the yearsI've found brilliance in events that don't go accordingto plan. That was the caselast fall when I visited.the Farmington River and saw anglers in every spot I wanted to flsh. I had to laugh; Indian Summer was in full swing with its warm days and cool nights, the maples were turning scarlet and orange, the white birch were a colorful yellow, and trout were on the feed. \{hywouldn't the river be crowded? At the bottom of a pool below feeder stream was a gravel bar that allowedsafepassageacrossthe river and my only chancefor some solitude. Safelyacross,I could wade upriver and fish the back side of an overlookedmid-river island. About halfway up the island was some pocket water. It necked down into a small, shallow riffle that turned into a pool. The pool bent toward shore and cut under a bank. It bounced off some big rocks at the bottom and was a beautiful piece of water, all rolled into a 30-vard stretch. Shortly, I saw a good brown perform a splashy rise near one of thoserocks.Then another,and another. I inspectedthoserocks,and sawthe shucksthat explainedthose rises.Isonychia! The first time I encountered these rich, eggplant-colored bugs,which are commonly called mahogany duns or slate-wing duns, I spent an entirely frustrating day changing from emergers to a wide variety of dries to a slew of nymphs with no luck. It was only during the final minutes of the day,when I botched a cast that put a lot of drag in my drift and fast motion to the fly, that a big bror,rmwhacked that speeding nymph. Since that time I've always used a fast swing when fishing this hatch, and it's served well. 46 Autumn 2011
BY TOM KEER Here'swhy that tactic works: Isonychia swim almost as fast as a dace and they climb on structure like a stonefly to shed their nymphal shucks-basically Isonychia duns are unavailable to trout and, therefore, it's almost futile to fish a dry fly when an emergenceoccurs.But trout do chasedovrrnthose fastswimming nymphs, which I match with a size 12 or 14 Didas' Swimmin g Isonychi a Nymph. \tVhile those duns aren't important to trout, the Isonychia spinner is. It occurs most often in riffled water and can be matched by severalnoted patterns,including thelVhite-Gloved Howdy, anlsonychiaComparadun, or a Beck'sEmergevlsonychia.In contrast to fishing an Isonychia nymph, when fishing a spinner you'll want to employ a dead drift. There are two versions of Isonychiainthe fall, the larger bicolor and the smaller sadleri.Thehatch occurs on manv Eastern, Midwestern and some Southern tailwaters and freestone streams,including emergenceson such noted waters as Connecticut'sHousatonic River and Michigan's Ausable.Wherever it occurs, the hatch typically comes offin early afternoon and lastsinto dark-graciously, there's no need to set the alarm clock earlv for this one. Because Isonychia nymphs swim quickl,yyou can forgo some of the extreme technical fishing required to match other fall hatches; you know, those painful experiences that require magniSringglassesand 8X tippet. Instead,you can throw avariety of classicpatterns,such as the LeadwingCoachman,aZugBug or even a PheasantTail Nymph. My favorite pattern is Tim Didas' aforementioned Swimmin g Isonychia Nymph. Didas spins the bug on a swimming nymph hook, adding a component that lights up the fish. Looking back, it wasn't so bad getting displaced by those other anglers on the Farmington. Browns and a few rainbows rose for hours, I had a quiet stretch of river to myself, and I was in the middle of a hatch that didn't require much precision or stealth. I waited until the sun was long gone before I quit the stream, knowing I d be back the next day.