Common name:Brown trout
Scientific name:Salmo trutta
Alternative common names:
Finnock, peal, mort, and white trout (English).
Brown trout have a streamlined, spindle-shaped body which is silver to olive-brown, yellow, with small scales and covered with large reddish-brown spots. In South African dams, this species can grow up to 75 cm in length and over 6 kg in weight, whereas in rivers, smaller specimens are found. This fish feeds on invertebrates, insect larvae, flying insects, and molluscs, as well as fish and frogs.
Where does this species come from?Europe.
What is its invasive status in South Africa?Brown trout is not listed as an invader in any law in South Africa. Brown trout is proposed as a Category 2 invasive species in proposed amendments to the Alien Invasive Species Regulations (February 2018). These regulations have not been passed into law, to date.
Where in South Africa is it a problem?Southern and Eastern Cape, the Drakensberg in KwaZulu-Natal and highland areas of Mpumalanga and Limpopo Provinces.
How does it spread?Self-sustaining populations are known from several river systems but they are sensitive to water quality and not as widespread as the rainbow trout.
Why is it a problem?Brown trout have been linked to the decline of indigenous fish to predation and competition, most notably the Maloti minnow (Pseudobarbus quathlambae) in KwaZulu-Natal.
What does it look like?Description: Brown trout have a streamlined, spindle-shaped body which is silver to olive-brown, yellow, with small scales and covered with large reddish-brown spots. It is a medium-sized fish, growing to 6kg or more and a length of about 75cm. They grown larger in dams and smaller in rivers. It has a very small scales and small fins. Habitat: Brown trout form stream-resident populations, typically in high-altitude streams, but sometimes in large rivers. They are more likely to be found near submerged rocks & logs, undercut banks, and overhanging banks. They can also be found in heavy and strong currents. They are sensitive to water quality and prefer cold, mountain streams and rivers. Breeding: A typical female produces about 2,000 eggs per kilogram of body weight when spawning. Breeds in autumn or early winter.