Salmo trutta

History of Spread

Salmo trutta (Brown Trout) is native to 'Iceland, Ireland, Great Britan, North Africa (northern Morocco, Algeria, Tunisia) and Eurasia (Spain to northern Scandinavia, eastward to the Timaskiy-Ural mountain ranges, southward into Lebanon, tributaries of the Caspian Sea in Turkey, southeastward to the Amu Darya drainage of the Aral Sea, through Afghanistan to West Pakistan, Corsica, Sicily and Sardinia)' (Courtenay et al. 1984). This trout frequently develops anadromous populations in coastal regions (Scott and Crossman 1973).

Salmo trutta were first stocked in North America in 1883, in the Pere Marquette River, MI and soon were widely introduced in North America by the United States Fish Commission (USFC) and many state agencies, and, in many states, are stocked annually to the present day. This species has been stocked in 47 U.S. states (Fuller et al. 1999). Thirty-six states have established populations, but attempts to establish the species in FL, OK, OH, and KS were unsuccessful (Courtenay et al. 1984). Anadromous populations of S. trutta are known on the Pacific Coast from British Columbia, and are suspected to occur in the Columbia River and San Francisco Bay as well (Bisson et al. 1986; Dill and Cordone 1997; Scott and Crossman 1973). Worldwide, S. trutta has been introduced to tropical mountain regions and temperate habitats in India, South Africa, New Guinea, Australia, New Zealand, and South America (Lever 1996).

On the Atlantic Coast of the US, established populations of S. trutta occur in inland and coastal streams from the Great Lakes (Mills et al. 1993) and Maritime Provinces south (including the Hudson River Basin, Mills et al. 1997) to upper Chesapeake Bay. In the Potomac River and southward, S. trutta are confined to upper Piedmont and Mountain regions (Jenkins and Burkhead 1993; Lee et al. 1980). Anadromous populations are known to occur at least as far south as Long Island NY (Johnson 2000), but in Chesapeake and Delaware Bay, these trout appear to be just occasional strays ('boundary residents') in estuaries.

The first S. trutta in VA were received at the Wytheville VA hatchery 1885, and the first VA stockings in the Potomac drainage took place in 1893-94 (Jenkins and Burkhead 1993). Detailed records of stocking in the Chesapeake region of MD and PA are not included in USFC records, and so must have been done by the state fish commissions in the late 1880s-early 1890s. Salmo trutta were considered 'well-established' in PA, NY, and MD by 1893 (Bean 1893).

Potomac River- Salmo trutta has established populations in the mountain tributaries of Shenandoah and a small one in Difficult Run VA, just below Great Falls (Jenkins and Burkhead 1993).

Patuxent River- Salmo trutta was stocked in upper Piedmont tributaries (Mansueti 1950).

Susquehanna River- Salmo trutta is frequently collected from the Susquehanna below Conowingo Dam (McKeown 1984).

Upper Bay and Tributaries -Salmo trutta 'may be expected in upper Chesapeake Bay during the cooler months'and in the 'lower reaches of MD tributaries' (Musick 1972a). A specimen was caught in a pound net at 'Cedar Point Hollow, Chesapeake Bay'in 1943, but since the Bay has many Cedar Points, the exact location is unclear (U.S. National Museum of Natural History 2001).

Eastern Shore Tributaries - In DE, the last trout stockings of the year are Salmo trutta because of their higher temperature tolerance (Raasch and Altemus 1991). They are stocked in MD also, and do not survive the summer (McIninch 1995, personal communication).

History References - Bean 1893; Bisson et al. 1986; Courtenay et al. 1984; Dill and Cordone 1997; Fuller et al. 1999; Jenkins and Burkhead 1993; Johnson 2000; Lee 1976; Lever 1996; Mansueti 1950; McKeown 1984; Mills et al. 1993; Mills et al. 1997; Musick 1972a; Raasch and Altemus 1991; Schwartz 1963; Scott and Crossman 1973; Smith and Bean 1898; U.S. National Museum of Natural History 2001

Invasion Comments