PO Box 1273Helena, MT 59624-1273 • Fax 406-443-0788 800-874-4171e-mail: orders@thebookmailer.com
Search~> Flies - Gear - Supplies - Stories - AND everything else IMPORTANT: This database search does not cover our Books, Audio, Video, Software, Gift items. It searches the Flies, Gear, Supplies, Stories, and ALL other information on our site. If you are looking for a book, media, or gift item, please use this search instead.

Fly-fishermen endow the trout with the beauty, nobility and intelligence of a worthy adversary. It's easy to attribute these qualities to a fish who snubs a perfect presentation in a fit of selective temper.

Selective feeding, however, is simply a survival mechanism for fish that live in flowing water. It's not a result of intelligence; just the opposite, it's due to lack of reasoning ability, an instinct that has developed in trout because of biological pressures that have nothing to do with fly-fisherman.

A trout feeds selectively because this is an efficient way to gather insects. A fish, possessing a very small energy reserve, has to gain more energy than it expands as it feeds to survive. By holding in a single area and feeding in a set rhythm, a process of choice, the trout accomplishes this economy of motion.

There's an equation that illustrates whether or not a concentration of insects is important enough to trigger selective feeding:

As a trout feeds on a single type of insect it begins to key on visible characteristics. The recognizable features of an individual insect become the stimulae that trigger the feeding response -- and as long as the fish responds each time only to a recognizable stimulus it doesn't waste energy by grabbing at pieces of stream debris.

But because a trout doesn't have enough intelligence it cannot pick and choose. It cannot reason, "There's a big stonefly. That'll make a nice change from these caddis flies I've been eating." So it becomes locked into the visible characteristics of one type of insect.

The need for this instinct that keeps a fish from chasing all over a stream is proportionate to the size of a trout, because the greater the size the more energy expended with each movement. The bigger trout, before shifting from a fish to an insect diet, therefore requires a heavier concentration of easily gathered bugs.

How rigidly trout stick to a selective feeding pattern also depends on the velocity and clarity of the water. The clearer the water, the better the visibility for identification; the slower the water, the more deliberate the rise rhythm for better recognition.

Most fly-fishermen know that trout rising to pluck insects from the surface often feed selectively, but these same fishermen, because they can't see precisely what's happening underwater, don't know that trout foraging under the surface also feed selectively.

To consistently catch trout, either on a dry fly or a nymph, the angler has to be able to answer four questions that solve the problem of selective feeding:

With surface feeding, three of the questions -- how, where, and what -- can be answered by direct observation. The fourth question, how-to, is answered during periods of selectivity by matching the dry fly to the important visible characteristics of the natural insect.

For nymph fisherman these questions pose much greater problems. The answers, based in indirect observation at best, require a better knowledge of aquatic insects, a better understanding of trout feeding habits, and a better awareness of underwater imitation.