Fish of alpine streams and lakes

Between biodiversity, adaptation and fragility

While walking along the trails from Pontboset to Champorcher, you might catch a glimpse of movement beneath the clear waters of the Ayasse or the high-altitude lakes. A hidden and fascinating world, home to native species, ancient adaptations and more recent arrivals. Here are some of the key inhabitants of this mountain ecosystem.

Marbled trout

A native species with a golden-brown body and dark marbled spots along its back and sides. Once common, it is now in sharp decline, threatened by habitat loss and genetic contamination from introduced species.

Rainbow trout

Native to northwestern America, non-native in Italy but now widespread. It has a distinctive pink stripe, especially bright during breeding season. It thrives in cool, well-oxygenated waters and is more tolerant than native species. Common in fishing reserves.

Italian grayling

A native species with a streamlined body and a large, green-yellow striped dorsal fin in adult males. It once populated the mid and lower stretches of the Dora Baltea River but has nearly disappeared due to high sensitivity to environmental change.

European bullhead (sculpin)

A bottom-dwelling fish with a squat body, large head, and scaleless skin. Its grey-brown mottled coloring helps it hide among gravel and rocks. Very territorial, it can fend off much larger fish.

Minnow (sanguinerola)

A small native fish (up to 10 cm), often found in shoals in mountain lakes and streams. Frequently introduced into alpine lakes as a natural food source for trout.

Bleak (alborella)

Found mainly in still waters, where it forms large shoals near the surface. It has a green hue with silvery reflections and is one of the most iconic species of valley-bottom lakes.

Why protect them?

These species are indicators of the health of mountain ecosystems. Learning about them helps us understand the fragility of these environments and the importance of protecting them.

To walk “Au fil de l’eau” is also to look below the surface, discovering a world of balance, natural history, and hidden life.