Reading the Water

Knowing where to put the fly is the single most important skill in trout fishing.

An angler who can read water but can't cast well will outfish a skilled caster who cannot read water—every time.

Reading trout streams can be tricky on some rivers, but there are some general principles that apply to trout just about anywhere you fish.

To learn how to read water, an angler must consider the habitat from the trout's perspective. A trout has three major concerns in finding a place to hold:

The trout needs cover to protect him from osprey, eagle, beaver, kingfishers, and other predators—including humans.

The trout must locate a lie that doesn't require him to expend any more energy than he will take in.

The trout needs food, so his lie must provide him with opportunities to feed frequently. Let's break down each factor:

Cover: Trout don't need much structure for cover. Trout will use rocks, fallen trees, limbs, undercut banks, weedbeds, roots, and even shade for cover. Depressions in the streambed make for good cover because the trout's back markings and the depth of the water make it difficult to spot.

Energy: Trout will rarely hold in fastwater for very long. During hatches, trout will move out into the riffles to feed, but will typically return to a less demanding holding spot when the hatch is over. If a trout were to hold in the faster water for too long, it would quickly burn up more energy than it could consume in insects or other food. Trout will hold in the slower water, near the faster water—the water that carries food.

Food: Food is the main thing on a trout's little mind. They look for food all day long, usually insects, and search out the places where those insects live and collect. Ever see those stretches of foam on the surface of a river? Those are floating cafeterias full of trapped insects, both dead and alive, and hungry trout eagerly line up alongside them for lunch.

Fish against the Grain
Let's dispel one myth right off the bat: Trout do not always face upstream. They certainly face upstream a great deal of the time—but not always.

If a trout holds in an eddy, it is entirely likely that since the water swirls around, his eyes might be trained downstream instead. Angular cutbanks where trout might hide can make trout face across stream.

Trout will hold around rocks, but since the biggest fish get the best lies (the lie with most cover, the least resistance, and the most food), other fish will hold in several places around the rock, and not always upstream.

Water running downstream takes circuitous routes, and as such, trout will face whatever direction the water happens to be bringing them food.

Be Edgy
A simple and effective method to read water is to think "edges" or "seams." These occur where the faster water meets the slower water, places where the water is broken by a rock, a limb, or a different current. Look for edges where there is any change in the water, such as where a chute of water dumps through a channel, leaving the fastwater churning in the middle. The edges of the fastwater are where the trout will be holding. In a pool, the smaller trout will hold at the edges of the head of the pool while the larger trout will hold at the edges of the tail of the pool. The current through the pool will bring the fish a continuous supply of food while they sit on the sidelines, rising or cutting out into the food line only when they spot a piece of pie or a cut of meat that pleases them. So think edges and seams. Cast your pattern in the seam between the quick current and the slower current and you'll be surprised by how many more hookups you'll get.

Article © Mark D. Willliams, 2000