Salmo trutta Linnaeus, 1758
Sea trout
Salmo trutta
photo by Lorenzoni, M.

Family:  Salmonidae (Salmonids), subfamily: Salmoninae
Max. size:  140 cm SL (male/unsexed); max.weight: 50 kg; max. reported age: 38 years
Environment:  pelagic-neritic; freshwater; brackish; marine; depth range 0 - 28 m, anadromous
Distribution:  Europe and Asia: Atlantic, North, White and Baltic Sea basins, from Spain to Chosha Bay (Russia). Found in Iceland and northernmost rivers of Great Britain and Scandinavia. In Rhône drainage, native only to Lake Geneva basin, which it entered after last glaciation. Native to upper Danube and Volga drainages. Introduced widely. Several countries report adverse ecological impact after introduction.
Diagnosis:  Dorsal spines (total): 3-4; Dorsal soft rays (total): 10-15; Anal spines: 3-4; Anal soft rays: 9-14; Vertebrae: 57-59. Fusiform body (Ref. 51442). Head little and pointed (Ref. 51442). Mouth large, extending mostly after the eye and has well developed teeth (Ref. 51442). Teeth on shaft of vomer numerous and strongly developed (Ref. 7251). Caudal fin with 18-19 rays (Ref. 2196). Caudal peduncle thick and rounded (Ref. 51442). Little scales (Ref. 51442). Body is grey-blue colored with numerous spots, also below the lateral line (Ref. 51442). Blackish colored on upper part of body, usually orange on sides, surrounded by pale halos. Adipose fin with red margin.
Biology:  Found in streams, ponds, rivers and lakes (Ref. 5951). Individuals spend 1 to 5 years in fresh water and 6 months to 5 years in salt water (Ref. 51442). Juveniles mature in 3-4 years (Ref. 6885). Lacustrine populations undertake migration to tributaries and lake outlets to spawn, rarely spawning on stone, wave-washed lake shores. Spawns in rivers and streams with swift current, usually characterized by downward movement of water intro gravel (Ref. 59043). Spawning takes place normally more than one time (Ref. 51442). They prefer cold, well-oxygenated upland waters although their tolerance limits are lower than those of rainbow trout and favors large streams in the mountainous areas with adequate cover in the form of submerged rocks, undercut banks, and overhanging vegetation (Ref. 6465). Life history and spawning behavior is similar to the salmon Salmo salar (Ref. 51442). Each female produces about 10.000 eggs (Ref. 35388, Ref. 51442). Mainly diurnal (Ref. 682). Sea and lake trouts forage in pelagic and littoral habitats, while sea trouts mainly close to coast, not very far from estuary of natal river (Ref. 59043). Juveniles feed mainly on aquatic and terrestrial insects; adults on mollusks, crustaceans and small fish (Ref. 26523, Ref. 51442). Marketed fresh and smoked; eaten fried, broiled, boiled, cooked in microwave, and baked (Ref. 9988).
IUCN Red List Status: Least Concern (LC); Date assessed: 05 March 2010 Ref. (130435)
Threat to humans:  potential pest


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