White fly hatch means good fishing

August 05, 2000

White fly hatch means good fishing

Outdoors | by Bill Anderson

Most fishermen know that aquatic insects make up an important part of the diet of favorite gamefish like trout and bass.

Stream surveys by fishery biologists usually indicate a large number of aquatic insects, primarily made up of caddisflies and mayflies. In fact, the species found can serve as a good indicator of the overall water quality of a stream because certain insect species are intolerant of pollution and are found in only the best quality streams.

Fish are opportunistic feeders and take advantage of all food sources. During the course of the spring, summer and fall, insect hatches come and go and the fish will switch from one to the other as they become available. Some hatches go on for days and weeks and others may only last for a day or two.

In our part of the country, one of the most prolific hatches is the white miller, or white fly hatch. The white miller is a mayfly and is most often found in slow moving streams and rivers with mud or silt on the bottom.


The flies hatch in the late summer and often hatch in swarms on late summer evenings. Even non-fishermen know the flies as the ones that swarm to lights and gas lanterns. When the hatch is going strong, the flies can become quite a nuisance and will drive people to the darkness to get away from the swarming insects.

Fish react to this food source with lots of excitement. It's exciting to be standing thigh-deep in a river, the surface coated with dead mayflies and fish of all sizes slashing and slurping the food from surface film.

Most of my experience with this hatch has been associated with smallmouth bass fishing. Smallmouths are very attuned to taking insects from the surface, and the white miller hatch seems to get them particularly revved up.

River fishing usually begins in the very late evening as the nymphs begin emerging from the bottom and float on the surface as duns. The white miller is one of the mayflies that hatches as a dun and molts to a spinner in the same evening. The fish take the nymphs as they emerge and will also take the duns while they are on the surface. But it is the spinner fall that creates the big excitement.

The flies return to the river in great swarms that hover above the water as they mate. When mating is done, the males die and drop to the water. The females deposit eggs and also drop to the water dead or dying. Fly fishermen refer to this as the spinner fall. At the peak of the white miller hatch, the spinner fall can literally blanket the river's surface.

Fishermen have several options when fishing during the white miller hatch. If you are fly fisherman, this is a prime time opportunity. The fish aren't particularly selective feeders and a durable dry fly pattern that is close in size to the natural is all you need to be in business. The western dry fly patterns like the White Wulff and Humpies that use deer hair are durable and have excellent floating properties. This is important when you are fishing in the dark and you don't want to change flies after every other fish.

You don't have to be a fly fisherman to take advantage of this opportunity. Small surface lures can draw plenty of strikes. The plastic jerk baits can also be very effective when fished unweighted, which keeps them near the surface.

The white miller hatch can last for several weeks. The hatch usually peaks in mid-August, but you can have daily activity well into September. As time goes on, the flies seem to hatch later in the evening, until most activity will occur just before and after dark.

Many of us consider the white miller hatch a milestone event for the fishing season. If you give it a try, it will probably be a favorite event on your fishing calendar as well.

Bill Anderson writes a weekly outdoors column for The Herald-Mail.

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