In my circle of angling friends, the subject of caddisflies rarely comes up. That is, unless one of us happens to be on a river where caddis are actually hatching. Then there will be talk, most likely fraught with frustration.

The literature available on Catskill caddisflies indicates there are about five important species. Perhaps that is part of the issue. There are many more species of mayflies that hatch every year, which we wait for, follow and fish, beside caddis.

While there are fewer species of caddis than mayflies in Catskill rivers, there appear to be even fewer caddisflies immediately downstream of the Pepacton Reservoir—although my friend Jamie ran into a decent hatch at our camp on May 12, so there is the possibility that the distribution of caddisflies, like that of some species of mayflies, is negatively impacted by prolonged exposure to cold bottom-release water.

While I don’t know the answer to that question, I do know that the number of caddisflies and mayflies, along with other species of aquatic insects, increases dramatically below Shinhopple. The water temperatures in that reach of river are considerably warmer than they are close to the dam. Is that why those of us who fish close to the Pepacton Reservoir never see a lot of caddisflies? Is the water just too cold?

 As far as I know, all species of caddis build a case, made up of sticks, or grains of sand, at some point in their life cycle. Even the free-living forms construct a case, in order to pupate before emergence. That’s how caddis spend their lives as immature insects—living within a case.

Caddisflies attach their cases to the river stones, so many species are sedentary. However, there are some species, like the strawman, that move about freely.

Unlike mayflies and stoneflies, which change from nymphs directly to adults, caddisflies undergo a pupation stage, where the larvae go through a resting phase of one to two weeks before emergence. As a result, caddisflies go through a complete metamorphosis, while mayflies and stoneflies do not. While mayflies hatch at the bottom or at the surface and float along, sometimes for several minutes, before flying off, caddis do not. Caddis pupae either float or swim to the surface, where they immediately leave the pupal skin and fly off. Other species hatch at the bottom or in the water column on the way to the surface.

Because of their life cycle, caddis do not ride the water’s surface like mayflies; as a result, there is little dry fly fishing opportunity during emergence. However, on occasion, female caddis will bring trout to the surface as they go through the egg-laying process. Or perhaps a decent breeze will cause a number of caddis to be blown onto the water’s surface, creating a chance for the dry-fly angler.

Because of the way caddisflies emerge, fly fishing during a hatch usually means fishing some type of underwater pattern, either pupa or emerger, as the larvae make their way to the surface and leave the water. This type of hatching behavior, where the pupae or emerged adults swim or float through the water column on the way to the surface, is what causes trouble for some fly fishers. I know it has for me.

Based on my experience as a fly fisher, I’ve had little success hooking trout during caddis hatches, as fish splashed all around, feeding on the emerging flies. And I’m not unique. One day, many years ago, during my time at the Wulff School of Fly Fishing, Joan and Lee invited me to go fishing. We went to Cairns Pool on the Beaver Kill. Upon arrival at the river, we were treated to an enormous caddis hatch, with trout chasing emerging flies. Some of those fish were actually leaping out of the water as they chased hatching caddis. Do you know, not one of us hooked a trout, most likely because we could not mimic the behavior of the emerging flies. As a result, what I would call three pretty fair anglers went fishless on the Beaver Kill that afternoon. That is precisely what hatching caddisflies can do to even experienced fly fishers.

Anglers that are successful in catching trout during a caddis hatch have learned to fish their pupa or emerger imitations, to match the movement of the hatching flies. That means those anglers have figured out that it is necessary to raise their flies through the water column, as those flies float downstream. To do that, the flies must be cast upstream on a short line, allowed to sink and the rod lifted, as the flies float along. That technique causes the artificial flies to behave in the same manner as the emerging caddis.

Fly fishers who have to opportunity to fish on rivers, where there is a lot of caddis activity, learn the methods that result in success. Those of us who happen on the rare caddis hatch are more often than not frustrated with our inability to hook trout, as feeding activity goes on all around, and hungry trout chase the emerging flies.

While I have learned to successfully fish mayfly nymphs along the bottom when necessary, I have not succeeded in hooking trout while they feed on emerging caddisflies. Hopefully, I’ll find some hatching caddis in the near future, so I can work on and perfect the techniques I’ve described in this columnn.