Salvelinus fontinalis

Analyses of mtDNA variation indicate that diversity is highest in the southern part of the range and lowest in the north; mid-Atlantic populations are transitional between these regions of high and low haplotypic diversity (Perkins et al. 1993, Hayes et al. 1996, Hall et al. 2002).

Genetic data from 30 populations representing six major river drainages in Maine "provided evidence for the role of contemporary landscape features in shaping the observed pattern of genetic diversity at smaller geographic scales (within and among populations within river drainage). On a broader geographic scale, contemporary landscape structure appeared to be only a minor factor determining the observed pattern of genetic structuring among drainages" (Castric et al. 2001).

Hybrids between this species and Salmo trutta and Salvelinus namaycush are known. Extinct subspecies agassizi (silver trout) sometimes has been regarded as a distinct species. The aurora trout, maintained only as hatchery stocks in lakes in the Temiskaming District of Ontario, may be a distinct subspecies, S. f. timagamiensis (Page and Burr 1991).

This species is native to most of eastern Canada and the northeastern United States, from Newfoundland to the southwestern side of Hudson Bay, and south in the Atlantic, Great Lakes, and Mississippi River basins to Minnesota, northeastern Iowa, Wisconsin, Lake Michigan (but not Illinois streams), Chagrin River (Lake Erie drainage) in northeastern Ohio, northern New Jersey, New England, and southward in the Atlantic and Mississippi basins of the Appalachian Mountains to northern Georgia (Smith 1979, Trautman 1981, Becker 1983, Cooper 1983, Smith 1985, Etnier and Starnes 1993, Jenkins and Burkhead 1994, Menhinick 2001, Behnke 2002, Hartel et al. 2002, Moyle 2002, Bailey et al. 2004). Sea-run populations at least formerly extended from the Atlantic provinces of Canada to Long Island, New York (Scott and Crossman 1973), including Hudson Bay (Behnke 2002). Brook trout have been introduced in most of the lower peninsula of Michigan, western North America, and temperate regions in many other parts of the world.

This species is represented by a large number of subpopulations and locations.

Poor land management associated with agriculture and urbanization ranks as the most widely distributed negative impact on stream populations of brook trout across the range in the eastern United States (Hudy et al. 2005, Trout Unlimited 2006). Non-native fishes rank as the largest biological threat to lake populations (Hudy et al. 2005, Trout Unlimited 2006).

Range has contracted in southern Appalachian region due to impacts of logging, fires, river impoundment, road and railroad construction, land clearance for agriculture and human habitation, and encroachment of introduced rainbow trout and brown trout (Larson and Moore 1985, Galbreath et al. 2001). Introduction of hatchery-reared brook trout from the northeastern United States has also affected native populations, but genetic sampling of populations in the Pigeon River system in North Carolina indicates that a high proportion of sampled populations consist of unaltered native fish (Galbreath et al. 2001).

Sea-run populations in eastern Canada and the northeastern United States were decimated over the past 200 years by overharvest, habitat degradation, and stocking of hatchery-reared brook trout and other non-native salmonids (Ryther 1997).

Historically, most of Lake Superior's 3,000 miles of shoreline and tributary streams supported coaster brook trout populations. In the mid-1800s, unregulated fishing decimated these stocks, and in-stream habitat loss due to wide-scale logging further reduced numbers and prevented stocks from recovering (USFWS, Region 3). Exploitation of coaster stocks and demands on their habitat accelerated in the twentieth century. The opening of the Lake Superior watershed by road, rail, and water removed protection by isolation. Fishing pressure increased, and habitat damage from hydroelectric dams, road and railway construction, and mining probably also contributed to the decline. In some areas, sea lamprey (Petromyzon marinus) predation, which peaked in the late 1950s (Curtis 1990), and the introduction of Pacific salmon and rainbow trout (Onchoryhychus mykiss) and brown trout (Salmo trutta) were additional stressors that probably reduced coaster abundance and distribution (Newman and DuBois 1996). By the mid-1900s only a handful of tiny remnant stocks still existed (USFWS, Region 3).

In general, brook trout populations respond most negatively to factors that decrease survival of large juveniles and small adults and that decrease growth rates of small juveniles (Marschall and Crowder 1996).