Biology

At the sea, it occurs along coast at depths of up to 50 m. Resident part of populations live in streams and uppermost reaches with fast current, cold clear water and stone or gravel bottom. Parrs and resident adults prey on aquatic and terrestrial invertebrates. Anadromous and large lacustrine individuals feed predominantly on fish, but also take large crustaceans. Undertakes migration to hill streams. Usually spawns in the upper reaches of rivers with fast current. Damming hinders both migrating juveniles to reach the sea and returning adults to reach spawning sites. Species survival depends solely on resident populations (Ref. 59043).