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How to read a trout stream

Fish lie where the current brings them food without making them work hard. Learn to spot those places, approach them from downstream, low and quiet, and you will catch more fish than a better caster who walks straight up to the water.

The parts of a stream

A stream is a repeating pattern.

• Riffle: shallow, fast, broken water over stones, full of insect life and oxygen.
• Run: deeper, steadier water below the riffle.
• Pool: deep, slow water where the stream widens or turns.
• Tail of the pool: where it shallows and speeds up again.
• Pocket water: fast water broken by boulders, with small calm pockets behind them.

Along all of these run seams, where fast water meets slow.

Where fish lie

A fish needs food brought by the current, shelter from predators, and a place out of the fast water. Look where all three meet:

• along seams, in the slower water beside the fast;
• in front of and behind rocks;
• at the head of a pool, where the riffle tips food into deeper water;
• in the tail of a pool, especially in the evening;
• under overhanging banks and trees, and near weed beds;
• in deeper runs in hot weather, and in riffles when insects hatch.

Fish face upstream, waiting for food to come to them.

Approach unseen

Fish in clear streams scare easily, and every fish you frighten scares others.

• Move upstream. Start at the bottom of a stretch, so that you come from behind the fish.
• Keep low. Crouch or kneel.
• Wear quiet colours: greens, browns and greys.
• Tread softly. Fish feel vibrations through the bank.
• Watch your shadow and your line. Neither should fall on the fish.
• Fish the near water first, then further out.

The dry fly upstream

When fish are rising:

1. Cast a metre or two upstream of the rise, so that the fly drifts down to the fish.
2. Let the fly drift at the same speed as the current. The enemy is drag: the line pulling the fly faster than the water, or across it. Fish ignore a dragging fly.
3. Avoid drag by leaving a little slack in the leader, and by mending: flipping the line upstream with the rod tip as it drifts.
4. Gather the slack as the fly comes back to you.
5. When the fish takes, lift the rod smoothly. Wait a moment for the fish to turn down, especially a big, slow one.

Nymphing upstream

Most of the time fish feed under water, so a nymph catches more fish.

• Cast a weighted nymph upstream, so that it sinks close to the bottom before it reaches the fish.
• Let it drift naturally, gathering slack.
• Watch the end of the line or a strike indicator. If it stops, twitches or moves sideways, lift gently.

If you never touch the bottom, the nymph is not deep enough. Add weight or lengthen the leader. If you catch the bottom on every cast, go lighter.

Wading

• Wade only where you can see the bottom, in water below your knees to start with.
• Move slowly, sliding your feet.
• Never wade through water that you or another angler will fish.
• Stay out when the river is high or coloured.

Keep a record

Sketch each stretch and mark where the fish were, what they took, the time, the weather and the water level. After a season, the sheet tells you where to start.

This guide is based on Chapter 7 of Fly Fishing in South Africa.