Every morning here on the Bighorn River we're having wonderful hatches of tan caddisflies. In recent years the heaviest caddis hatches have been black and have occurred in the evening. No one knows for sure what happens to change the way hatches occur but one thing is for certain - all the anglers on the river are enjoying the dry fly fishing.
Elk Hair Caddis
Elk Hair Caddis, named for the elk hair used to make the wing, are working very well. They float well and are easy to see on the surface.
Caddisflies have three stages in their life cycle. The first is the worm-like larva. The larva lives in the stream bottom, often encased in a small cylindrical cocoon-type abode made out of sand, grit, and tiny pieces of bark and leaves which is attached to the underside of submerged stones. At a certain time, usually in about a year, the larva leave the cocoon and swim to the surface. This is the pupa stage. It's very brief but very important because the fish love to feed on pupae as the insects are readily available in the water column. During this stage the pupa will shed it's larval shuck and unfold it's wings. When it gets to the surface the wings are unfolded (like the photo) and the insect is ready for flight. These caddis adults will often skitter and dance around on the surface for a couple seconds before taking flight, getting the attention of the fish. Once in flight it is no longer available to the fish until the females return to deposit their eggs on the water, usually a day or two later.
Fishing During a Caddis Hatch
Caddisflies come in all sizes and colors, the most common being tan, olive, and black. We're fishing size 16 here this week but there are many caddis that are larger or smaller.
Sometimes it's helpful to have a couple of different patterns in your box. I stood in one riffle and fished for 2 hours yesterday to rising fish who were eating tan caddis. After a while my tan elk hair caddis wasn't as effective as in the beginning, so I switched to another tan caddis the same size but tied a little differently. It fooled some of the fish that I had missed on the original fly. They were dialed into the elk hair and knew enough to avoid eating it again, but readily ate the second pattern - for awhile. In the two hours I fished 3 different tan, size 16, caddis patterns and caught fish on all three.
Sometimes when the rises are splashy it indicates that the fish are feeding on the pupae. Watch carefully to determine which stage of the insect the fish are eating. Often a pupa or caddis "emerger" trailed behind the dry is very effective.
Being observant and matching the hatch is the key to success during hatch times.
