Brown trout

Where does the brown trout live?

Home: Cool, clean rivers and lakes across Europe and western Asia.

In the wild it lives in these countries: Norway, the United Kingdom, Ireland, France, Germany, Switzerland, Austria, Spain.

Conservation status from the IUCN: not in danger.

The short profile

Fully grown: often 20–50 cm long, up to about 1 m. It weighs about 1 kilograms. On the menu: meat.

The story behind it

Brown trout hold their place in the current, facing upstream, and let the water bring food to them. A good spot is behind a boulder or under an overhanging bank, where the flow is slower but the drifting insects still pass close by. In the evening they rise to take mayflies from the surface, leaving rings that spread across the pool. In late autumn the females dig nests in clean gravel, turning on their sides and beating their tails until a hollow forms; these nests are called redds. The eggs lie hidden in the gravel all winter and hatch in spring, and the tiny fish carry a yolk sac like a packed lunch for their first days. Trout need cool water, and above about 20 °C they struggle, which is why shady trees along a stream matter so much. Some stay in their home stream all their lives and stay small; others run to the sea and come back heavy and silver. Most live around ten years, and a few live much longer.

Find it on the globe

Brown trout is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.

It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.