Bony fish · Salmoniformes · Salmonidae

Brown Trout

Salmo trutta

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

Its growth and its longevity are closely linked: fast-growing fish tend to live fewer years, while slow, steady growth goes with a longer life.

Weight

500 g – 24 kg

Size

18 cm – 1.4 m

Lifespan

5 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Irregular activity

Active at irregular times, by day or night depending on circumstances.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Unknown

FreshwaterCarnivore Variable activity Solitary Fish Freshwater

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Fun facts

Some exceptional populations, known as ferox trout, switch to an entirely fish diet and grow far larger and live far longer.
It feeds on aquatic insects and their larvae, on crustaceans, and — in larger fish — on smaller fish.
Some populations are anadromous, migrating between sea and river as the sea trout.
sentidosIt can detect subtle differences in the chemistry of its home river's water, which helps it navigate on spawning migrations.

Life cycle & biology

Skeleton type: Vertebrate - internal bony skeleton (fish)
Habitat & environment: Cold, well-oxygenated rivers, streams and lakes of Europe and western Asia; some populations are anadromous (the sea trout)
Birth weight: A ~12 mm alevin at hatching, still carrying its yolk sac
Size at birth: 12 mm long at hatching
Sexual maturity: 2-4 years
Gestation / incubation: 6-20 weeks depending on water temperature
Litter / clutch size: 200 to 1,500 eggs per female (a usual reference of ~2,000 eggs per kg of body weight)
Lifespan in captivity: Documented record of up to 25 years in some introduced populations

Sources consulted: ResearchGate (reproductive characteristics study); Wisconsin DNR; Animal Diversity Web; USGS NAS Species Profile; Bait Your Hook Blog; MDB Fish Fact Sheet; AnAge; JungleDragon; Woodland Trust; Fishing Planet Wiki; Grokipedia; FishBase; BioKIDS