Fish trap and stone weir (emergency knowledge)

Fish do not swim around aimlessly. They follow banks, edges, the margins of weed beds and the current, looking for food and cover. A trap makes use of this: a funnel or two angled walls guide fish to a narrow opening. Behind it lies an enclosed space in which the opening is hard to find from inside because it looks like part of the wall.

In the bottle trap the funnel is the upturned top of the bottle. A little bait inside attracts small fish; they swim in through the neck and then search along the walls for a way out. Small holes in the bottle let water and the smell of the bait flow through.

The tidal stone trap works with the water level instead of a funnel. At high tide the low wall is under water, and fish swim over it near the shore. At low tide the water falls, and fish that turn back too late are left behind in the pool behind the wall.

The location matters more than the construction. A trap belongs in calm, shallow water near the bank where small fish are moving anyway: along weed margins, in small bays, in places with slow water. It must lie on the bottom, be weighted and be secured to the bank with a cord so the current cannot carry it away.

With a stone weir in a stream, the wide side of the V faces downstream, and at the narrow point a hand-wide opening leads into the pen. The pen must be closed all round and the stones must lie close enough together. Crucially, the whole stream is never blocked: beside the weir there is always enough passage for water and fish.

A trap is only as good as its checking. Checking morning and evening is the minimum. At every check you decide immediately: young fish, crayfish, frogs, protected or unknown species are released at once; a fish you need is stunned and killed at once.

The legal situation is clear: in Austria and Germany traps, weirs and fish pens are prohibited without special authorisation under fishing law, even for anglers with a licence. Only genuine danger to life with no help within reach can justify them. Anyone who can reach help does not build a trap.

The greatest danger to you is the water. Cold water quickly makes hands and feet numb, wet stones are slippery and current can knock you over. Only build in ankle-deep, calm water, never alone in current and never when the level is rising or a storm is coming. On the coast the incoming tide can cut off your way back – know the tide table and keep watching the water.

A forgotten trap keeps killing without anyone gaining from it. That is why every trap and every stone wall is dismantled completely after the emergency: stones back, bottles and cords taken away, rods scattered. Traps that could injure people, and poison, are off limits in every case.

A trap only makes sense in a genuine emergency lasting some time, when you stay in one place, water, warmth and shelter are already secured and you can check the trap regularly. Then it works while you deal with other tasks.

In all other cases it is out of place: in a short emergency, when help can be reached, in nature reserves and spawning waters, in fast or cold water and when you have to move on. Realistically a bottle trap only yields very small fish anyway – it does not replace rescue.

Stone weirs and traps are among the oldest fishing methods. Remains of old tidal stone traps are found on many coasts of the world, and woven willow traps were used by professional fishers in Europe for centuries. Precisely because these methods can be so effective, they are strictly regulated today.

Knowing about traps also helps you understand the rules: anyone who has seen how a trap keeps catching without supervision understands why anglers may only fish with rod and line, and why bycatch and checking matter so much.