Reading a shingle beach

A SHINGLE BEACH IS STEEP BECAUSE OF HOW WAVES MOVE PEBBLES. Water running up the beach carries stones with it; the backwash drains between them rather than over them, so it carries less back down. Material accumulates high up and the profile becomes steep. Sand behaves the opposite way, which is why a sand beach is flat and a shingle beach is not, and why the two are different fisheries rather than the same one with different stones.

WHAT FOLLOWS, AND ALL OF IT TRANSFERS TO ANY STEEP SHINGLE COAST IN THE WORLD.

DEEP WATER IS CLOSE IN. The steep profile continues below the waterline, so useful depth is reached within metres of the edge. This is the single most important consequence and it inverts the usual beach assumption: the long cast is frequently the wrong cast, and fish feeding in the trough at the base of the steep face are inside the distance most anglers are throwing over.

THERE IS A POWERFUL UNDERTOW. Water thrown up a steep face has to drain back, and it does so as a fast, concentrated flow down the slope, dragging shingle with it. That flow moves a lead, loads the line, and — for anybody standing in it — takes the ground out from under them. It is also what suspends food, which is why fish feed in it.

THE DRIFT RUNS ALONG THE BEACH. Waves arriving at an angle move material laterally, sometimes for miles. On a long shingle bank this sorts the stones by size along its length, and where the stone size changes, the ground beneath the water changes with it — which is why some stretches hold different species from others on what looks like a uniform beach.

THE SPECIES MIX FOLLOWS THE GROUND. Deep water close in brings species that would be well offshore on a shallow beach. Shingle and the coarse ground beyond it hold different invertebrates from clean sand, so the fish that feed on them differ too.

HOW TO READ ONE ON ARRIVAL. Find the STEP — the abrupt change of slope at the low water mark, best seen at low tide. Look for where the stone grade changes along the beach. Watch where the backwash concentrates, which marks a drainage channel. And look at what the sea has thrown up on the strand line, because it is a sample of what lives on the ground in front of you.

AND THE HAZARD IS THE SAME MECHANISM. A steep face of loose, mobile stones with deep water at the bottom of it and a strong backwash is difficult to climb and easy to fall down, and somebody who goes in is immediately out of their depth in moving water.