Mark Vinson - Fly Fishing Team USA Entomologist

Dr. Mark Vinson is a renowned entomologist who provides Fly Fishing Team USA his wealth of knowledge about streamside insects. When the Team travels to new countries, it can reliably depend upon Mark to provide authoritative information which aids in our strategies for flytying and insect identification.
Mark's extensive background serves his employment at the Western Bioassessment Center in Utah. The Western Bioassessment Center (a.k.a. BugLab) is a cooperative venture between Utah State University and the U.S. Bureau of Land Management. Their purpose is to encourage and foster scientifically sound watershed monitoring programs on public lands. Their goals are to increase the consistency and quality of aquatic resource assessments and provide clear, accurate, and timely information to resource managers and the public. The focus of their laboratory is the processing of aquatic invertebrate samples for government agencies and private environmental monitoring organizations.

If you are a beginning trout angler, you might have read or heard something about the aquatic insects that trout feast upon. Contrary to neophytes' general belief that trout exclusively eat Royal Wulffs and Wooly Buggers, trout only find those flies similar to their favorite food of mayflies, caddis flies and stoneflies. And half the time, just as with lures, fancy-looking flies catch the eyes of the angler more than the trout.

You will find in books that these common aquatic insects have been given fancy scientific names. The study of these insects is called entomology. Learning Latin names doesn't make you catch more trout. Learning the stages of the insects the trout eat will help you catch more trout. It never hurts to learn all you can but at least start with the basics of fly fishing.

Flies usually don't look exactly like the insect you are trying to imitate. They are imitative, suggestive, impressionistic. They look kind of like one of the insects trout eat. They look kind of like a stage of one of the insects trout eat. They provide the proper silhouette or shade or wing pattern or size or color of the insects trout eat. But they rarely look exactly like the insect.

The most abundant insects trout eat, the insects that you will be imitating with your selections of dry flies, wet flies and nymphs are mayflies, caddisflies and stoneflies. You can find the first two in almost any trout stream and stoneflies in many of them. The life cycles of each insect vary in length and process but in general, you will be trying to imitate the stages of the cycles whether the winged adult or the immature pupa.

Why Study the Stream-Bottom Macroinvertebrates?

Stream-bottom macroinvertebrates are an important part of the community of life found in and around a stream.

Stream-bottom macroinvertebrates are a link in the aquatic food chain. In most streams, the energy stored by plants is available to animal life either in the form of leaves that fall in the water or in the form of algae that grows on the stream bottom. The algae and leaves are eaten by macroinvertebrates. The macroinvertebrates are a source of energy for larger animals such as fish, which in turn, are a source of energy for birds, raccoons, watersnakes, and even fishermen.

Stream-bottom macroinvertebrates differ in their sensitivity to water pollution.

Some stream-bottom macroinvertebrates cannot survive in polluted water. Others can survive or even thrive in polluted water. In a healthy stream, the stream-bottom community will include a variety of pollution-sensitive macroinvertebrates. In an unhealthy stream, there may be only a few types of nonsensitve macroinvertebrates present.

Stream-bottom macroinvertebrates provide information about the quality of a stream over long periods of time.

It may be difficult to identify stream pollution with water analysis, which can only provide information for the time of sampling. Even the presence of fish may not provide information about a pollution problem because fish can move away to avoid polluted water and then return when conditions improve. However, most stream-bottom macroinvertebrates cannot move to avoid pollution. A macroinvertebrate sample may thus provide information about pollution that is not present at the time of sample collection.

Stream-bottom macroinvertebrates are relatively easy to collect.

Useful stream-bottom macroinvertebrate data are easy to collect without expensive equipment. The data obtained by macroinvertebrate sampling can serve to indicate the need for additional data collection, possibly including water analysis and fish sampling.

Fly Fishing Team USA gratefully acknowledges his assistance and generous support.