Picture by Chad Thomas, Texas State University - San Marcos

Salmo trutta

brown trout

Type Locality

Europe (Linnaeus 1758).

Etymology/Derivation of Scientific Name

Salmo: the Latin name for salmon of the Atlantic; trutta: the Latin name for trout (Scott and Cross 1973).

Synonymy

Salmo trutta (Linnaeus 1758:308).

Salmo fario (Linnaeus 1758:309).

Salmo eriox (Jordan 1926:141).

Salmo levenensis (Günther 1866:101).

Characters

Maximum size:  103 cm (Fuller et al. 1999).

Coloration: Red and black spots on head and body, many spots on gill cover, usually unspotted or vaguely spotted caudal fin. In streams, olive to dark brown above, silver sheen on yellow-brown side, white to yellow below; bold black spots on head, back, dorsal, and adipose fins, and extending below lateral line on side. Rust-red spots on side, usually orange or red adipose fin. Silver overall, often with X-marks above in large lakes and ocean (Page and Burr 1991).

Teeth count: Teeth developed on upper and lower jaws (premaxillary, maxillary, and dentary), usually many teeth on head and shaft of vomer, on palatines, on tongue in 2 rows, no hyoid teeth (Scott and Crossman 1983).

Counts: 120-130 lateral scales, usually 9 dorsal rays, and 10 branchiostegal rays (Page and Burr 1991).

Body shape:  Typically troutlike, elongate, compressed laterally (Scott and Crossman 1973).

Mouth position: Terminal (Scott and Crossman 1973).

External morphology: Breeding males have hooked lower jaw, rounded anal fin, and females have falcate anal fin (Page and Burr 1991).

Distribution (Native and Introduced)

U.S. distribution: Introduced from Germany (Needham 1969). Native to Europe, North Africa, and west Asia; introduced to North America in 1883 and now widely socked throughout south Canada and much of the U.S. Locally common (Page and Burr 1991).

Texas distribution:

Abundance/Conservation status (Federal, State, NGO)

Habitat Associations

Macrohabitat: Most stocking have been into cool, high gradient streams and cold lakes. In streams, adults live in pools, young occupy pools and riffles. Some sea-run populations have become establishes (Page and Burr 1991).

Mesohabitat:

Biology

Spawning season: Late autumn to early winter (Scott and Crossman 1973).

Spawning location: Shallow, gravelly headwaters (Scott and Crossman 1973).

Reproductive strategy: Females create redds in the gravel, in which the spawning fish deposit eggs and sperm. The process in repeated many times, and then the female covers the redd with gravel (Scott and Crossman 1973).

Fecundity: Larger fish deposit more eggs, in Canada, females age 5 and 6 averaged 2020 eggs, usually 4-5 mm in diameter (Scott and Crossman 1973).

Age at maturation:

Migration: 

Longevity:

Food habits: 

Growth:

Phylogeny and morphologically similar fishes

Atlantic Salmon have 2-3 large black spots on gill cover, no red spots on body, no red or orange on adipose fin; upper jaw reaches only to below center of eye (except in large males; Page and Burr 1991).

Host Records

Fungi (5), Protozoa (12), Trematoda (32), Cestoda (12), Nematoda (20), Acanthocephala (13), Leech (2), Mollusca (Glochidia), Crustacea (7) (Hoffman 1967).

Commercial or Environmental Importance

References

Fuller, P. L., L. G. Nico, and J. D. 1999. Nonindigenous fishes introduced into inland waters of the United States. American Fisheries Society, Special Publication 27, Bethesda, Maryland 613 pp.

Hoffman, G. L. 1967. Parasites of North American Freshwater Fishes. University of California Press, Berkeley, 486 pp.

Needham, P. R. 1969. Trout streams. Holden-Day, San Francisco, Calif. 241 pp.

Page, L.M., and B. M. Burr.  1991.  A Field Guide to Freshwater Fishes of North America, north of Mexico.  Houghton Mifflin Company, Boston, 432 pp.