Historically, the Esopus Creek was famous for its early spring runs of large rainbow trout, as well as some of its local personalities. Ray Smith was a local fly tier and sometimes a guide. It is reported that he guided notable sports figures such as Yogi Berra. 

Ray tied a large variety of snelled wet flies that he made for sale. (Snelled flies are wet flies that have a short section of leader material attached through the eye of a hook, making them easy to attach to the tippet.) Folkerts Brothers was the local sporting goods store. It sold Payne bamboo fly rods and Ray Smith flies, along with assorted other angling paraphernalia. 

In its heyday, anglers came from all over to fish the Esopus, hoping to hook one of the large rainbows that migrated into the creek and its many tributaries from the Ashokan Reservoir to spawn.  

 Of all Catskill rivers, the Esopus is the most an enigma in that after heavy rain storms, the Schoharie Reservoir turns brown because of the large clay deposits along the banks of its tributaries. That muddy water feeds the Esopus via the Shandaken tunnel, causing the Esopus to take on the same color. That off-colored water is unappealing to fishermen and not healthy for trout or the aquatic insect population.

Because of the muddy water, the Esopus is not as popular as it once was. In addition, the runs of large rainbow trout seem to have diminished considerably, although I have heard that some rainbows in the five-to-six-pound range are entering the river in late winter prior to spawning. I’ve also heard that those anglers brave enough to deal with the cold are landing some of those fish on flies. I’ve seen pictures of a few of those rainbows and they are very heavy for their length, indicating that they have adopted a diet of the abundant sawbelly population. 

That is definitely a change in feeding behavior, in that Ashokan rainbows were known to feed on insects and emerald shiners. So in adopting sawbellies as their primary food, Ashokan rainbows appear to be growing larger and heavier than in the past. Perhaps we’ll see some 10-pound fish in the future.

As far as fly hatches, the Esopus has almost all of the normal range of mayflies and caddisflies found throughout the region. From what I know and heard, the hatches are not as abundant as in other Catskill rivers, likely because of the impacts associated with the turbid water. There is a significant exception, however. 

Turbidity aside, Isonychia mayflies are extremely abundant in the Esopus. In fact, the Esopus has the best hatch of this mayfly in the Catskills. There is a spring hatch toward the end of June and a fall hatch that begins in September and extends into October. The spring flies hatch in the evening; the fall flies begin to emerge right around 2 p.m. The June flies for some reason are larger than the fall Isonychias. 

I’ve fished both hatches a few times and had more success in the fall. The last time I was on the Esopus during the June hatch, a friend and I did not move a single trout despite a lot of feeding activity, mostly on the nymphs. Unlike almost all other mayflies, Isonychias don’t rise from the bottom through the water column, and hatch on the way to the surface. Instead, they migrate to shore, and climb out on a riverside stone, where they emerge as duns. As a result, there is little surface-feeding activity with this species, unless there is enough wind to blow some of the duns back on the river. If that occurs, skidding a dry fly can bring some vicious strikes. Anglers fortunate enough to be streamside during a mating flight and resultant spinner fall could find success fishing the dry fly once the dying, spent flies fall to the river. 

Several years ago, two friends and I went off to fish the Esopus one early October afternoon. We planned to fish a reach about half a mile above the Five Arches Bridge, off a dead-end side road. We hit the river perfectly, in that there were shucks from previous Isonychia hatches all over the river stones. Around 2 p.m., more nymphs began to leave the river and hatch.

There was a pretty good breeze that afternoon, in which many of the newly hatched duns were blown back to the river, only to be picked off by hungry trout. We had excellent sport, fishing our examples of Art Flick’s size 12 dun variant to the rising fish.

While no very large rainbows were caught that afternoon, each of us landed enough 10-to-12-inch trout to be very happy anglers at the end of the day. In all the years I fished the Esopus, I never had another day like it.

So if you have the opportunity to be in the Esopus Valley with a fly rod, either in late June or from late September in to early October, make sure that you fish the Isonychia  hatch on that river. If you are fortunate enough to find an emergence of these large, slate-colored flies, you’ll be in for some exciting, but perhaps difficult, fishing. Like the green drake hatch on other Catskill rivers, the Isonychia hatch on the Esopus should not be missed. It is that good.