By Mike Lawson
Its caddis time on the Henry’s Fork! The American Grannom (Brachycentrus occidentalis) commonly called the Mother’s Day Caddis, ranks up there with the best hatches of the entire season on the Henry’s Fork and other western rivers. The emergence is often incredibly intense, and the sky can literally be clouded with freshly emerged or egg-laying insects. The pupae, usually green with a tan shroud, emerge at the surface. The pupae do not emerge as quickly as many other caddis species. They often float along the bottom before making their ascent to the surface where they drift until the adults free themselves from the pupal shuck. Prior to and during the hatch, an olive Partridge Caddis Emerger is a killer pattern. You can fish it deep before the adults start coming off, or in the surface film during the emergence. I like to use a size 16 olive EZ Caddis as the top fly, with a Partridge Caddis Emerger as a dropper about 12 inches below the dry fly. Another good dry fly is the Hemingway Caddis. This fly was originally created especially to match the Grannom Caddis adults.
The case making larvae of the Grannom build a square case from plant material. They are extremely important as a winter food source because they stay active throughout the winter while most mayflies overwinter as eggs. Like many caddisflies, it can be difficult to differentiate between the emerging adults and egg-laying females. The females drop to the surface or dive below the surface to lay their eggs. Either way, the surface is often covered with adults during the egg-laying process creating an exceptional opportunity for some fast dry fly action.
The only real relationship this insect has to Mother’s Day is if your mother is a die-hard dry fly fisher. The hatch almost always occurs well before Mother’s Day. In addition to the Grannom, look for good hatches of Baetis and Western March Browns. In reality, the last two weeks of April just might be the best dry fly fishing of the season on the Lower Henry’s Fork.
This year I’m especially excited about fishing these caddis flies. I’ve been grounded for the past six weeks from rotator cuff surgery on my right shoulder. No fishing! Today my surgeon gave me a get out of jail ticket with the go ahead to do some light casting. What is light casting? I just got back from my first session of physical therapy, and later I plan on doing more physical therapy on the river and follow the doctors’s advice with some “light casting.”
For more detailed information about the Grannom Caddis, please visit the hatch chart on our web site.
Got Caddis? The Henry's Fork does...
