The Brook Trout is a beautifully-colored fish, iridescent blue to green with yellow spots and sometimes orange to red spots with blue halos across its side. The back may darken to an olive green with dark, wavy, worm-like lines which are lacking in other salmonids. While their undersides lighten to a silvery white, their lower fins are orange with white margins. They have teeth located only in the front of their mouths. Average size of the fish is ten to twelve inches long and one to four pounds, but largest on record was over 14 pounds. The Brook Trout eats a wide variety of insects and small animals. A juvenile will eat insect larva, plankton, and small crustaceans while a larger adult may eat small fish and crayfish.

In the late fall the female will scoop out a shallow hole in the gravel of the streambed or lake bottom around the shoreline. The male and female together then extrude eggs and milt into the hole, the female then covering the fertilized eggs (100 to 5000, depending on her size) to incubate them during the winter. In two or three months the surviving eggs hatch. The young go through a couple of stages before they reach adulthood. During the fry and fingerling stages they eat plankton and as they grow into adulthood they will begin to eat insects and larger prey. The Brook Trout commonly lives its entire life in the same streams and lakes in which it was born or sometimes it may travel out to sea, returning to freshwater to spawn. Maximum life expectancy is about five years old.

Although the Brook Trout is more commonly found at high elevations in the cold water of mountain streams, rivers, lakes and ponds, it populates many watersheds in New England at nearly all elevations. It requires high oxygen content in the water and does not do well in water that gets above 68 degrees in the summer. The Brook Trout is distinguished as being the only trout native to New England waters: brown trout originated from Europe, and rainbow trout came from the northwest United States.

Occurs in clear, cool, well-oxygenated creeks, small to medium rivers, and lakes (Ref. 5723, 44894, 10294). Nerito-pelagic (Ref. 58426). In its native range, general upstream movements have been observed in early spring, summer and late fall; downstream movements, in late spring and fall (Ref. 28546, 28548, 28549, 28550). Some fish, popularly known as salters, run to the sea in the spring as stream temperatures rises, but never venture more than a few kilometers from river mouths. It may remain at sea for up to three months (Ref. 28546, 28549, 28551). Feeds on a wide range of organisms including worms, leeches, crustaceans, insects (chironomids, caddisflies, blackflies, mayflies, stoneflies and dragonflies (Ref. 5951), mollusks, fishes and amphibians (Ref. 3348, 10294); also small mammals (Ref. 1998). Stomachs of some individuals contained traces of plant remains (Ref. 1998). There are reports of introduced fish reaching 15 years of age in California, USA (Ref. 28545). Cultured for food and for stocking (Ref. 27547). Extensively used as an experimental animal (Ref. 1998). Marketed fresh and smoked; eaten fried, broiled, boiled, microwaved, and baked (Ref. 9988).

Brook trout are found as far south as Georgia in the Appalachian mountain range and extend north all the way to Hudson Bay. From the east coast their native range extends westward to eastern Manitoba and the Great Lakes (Willers, 1991). The fish has been introduced, very successfully in some areas, into many parts of the world including western North America, South America, New Zealand, Asia, and many parts of Europe (Scott and Crossman, 1973).

Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced ); oriental (Introduced ); neotropical (Introduced ); australian (Introduced )

Newfoundland to western side of Hudson Bay; south in Atlantic, Great Lakes, and Mississippi River basins to Minnesota and northern Georgia

Baltic sea, British Columbia, Canadian Exclusive Economic Zone [Arctic part], Canadian Exclusive Economic Zone [Pacific part], Coastal Waters of Southeast Alaska and British Columbia, FAO fishing area 67, Gulf of Maine, Gulf of St. Lawrence, Hudson Bay, Hudson Strait, New Zealand Exclusive Economic Zone, North East Pacific, North Pacific, North West Atlantic, North West Territories, Portugese Exclusive Economic Zone, Spanish Exclusive Economic Zone, Ungava Bay

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: 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.

Eastern North America, north to the Southern coast of Labrador, west to Minnesota, and southward to Georgia along the Allegheny Mountains.

North America: most of eastern Canada from Newfoundland to western side of Hudson Bay; south in Atlantic, Great Lakes, and Mississippi River basins to Minnesota and northern Georgia in USA. South America: Argentina (Ref. 9086). Widely introduced in temperate regions of other continents. Several countries report adverse ecological impact after introduction.

The brook trout's body is elongate with an average length of 38.1-50.8 cm, is only slightly laterally compressed; the body has its greatest depth at or in front of the origin of the dorsal fin (Scott and Crossman, 1985). Another physical characteristic of the brook trout is an adipose fin and a caudal fin that is slightly forked (Hubbs and Lagler, 1949). Brook trout have 10-14 principle dorsal rays, 9-13 principle anal rays, 8-10 pelvic rays, and 11-14 pectoral rays (Scott and Crossman, 1985). The brook trout also has a large terminal mouth with breeding males developing a hook or kype on the front of the lower jaw (Scott and Crossman, 1985).

The coloration of the brook trout is very distinct and can be spectacular. The back of the brook trout is dark olive-green to dark brown, sometimes almost black, the sides are lighter and become silvery white ventrally (Scott and Crossman, 1985). On the back and top of the head there are wormy cream colored wavy lines known as vermiculations which break up into spots on the side (Scott and Crossman, 1985). In addition to the pale spots on the side there are smaller more discrete red spots with bluish halos (Scott and Crossman 1985). The fins of the brook trout are also distinct; the dorsal fin has heavy black wavy lines, the caudal fin has black lines, the anal, pelvic and pectoral fins have white edges followed by black and then reddish coloration (Scott and Crossman, 1985).

Range mass: 1 to 6 kg.

Range length: 38.1 to 50.8 cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Dorsal spines (total): 3 - 4; Dorsal soft rays (total): 8 - 14; Anal spines: 3 - 4; Analsoft rays: 8 - 14; Vertebrae: 58 - 62

Length: 40 cm

Maximum size: 860 mm SL

to 86 cm SL; max. weight: 9,390 g.

86.0 cm SL (male/unsexed; (Ref. 7248)); max. published weight: 9,390 g (Ref. 4699); max. reported age: 24 years (Ref. 72501)

Distinguished by the combination of dark green marbling on its back and dorsal fin and by the red spots with blue halos on its sides (Ref. 27547). Pelvic fins with axillary process; caudal nearly straight or with a shallow indentation (Ref. 27547). Color varies, but generally rather green to brownish on back, marked with paler vermiculations or marbling that extend onto the dorsal fin and sometimes the caudal; sides lighter than back, marked with numerous pale spots and some red spots, each of the latter surrounded by a blue halo; anal, pelvic and pectoral fins with a white leading edge followed by a dark stripe, the rest of the fins reddish (Ref. 27547). In spawning fish the lower sides and fins become red (Ref. 27547). Sea-run fish are dark green above with silvery sides, white bellies and very pale pink spots (Ref. 27547). Caudal fin with 19 rays (Ref. 2196).

Brook trout are found in three types of aquatic environments: rivers, lakes, and marine areas. Their living requirements in these environments are very specific. The freshwater populations occur in clear, cool, well-oxygenated streams and lakes (Scott and Crossman, 1985). Brook trout thrive in these environments with temperatures that remain below 18.8 C and where there is little to no siltation (LaConte, 1997). Stream dwelling brook trout require three habitat components, which include resting areas in pools, feeding sites near riffles or swiftly flowing water, and escape cover which normally is found along undercut banks, under woody debris, trees or large rock ledges ("Brook Trout," 1987). Brook trout that reside in marine environments migrate there from freshwater tributaries and tend to stay close to river mouths.

Habitat Regions: temperate ; saltwater or marine ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams; coastal ; brackish water

Other Habitat Features: estuarine

benthic

anadromous; found in cool, clear streams and lakes, most venture out to the sea for 2-3 months of the year

Depth range based on 27 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1 sample.

Environmental ranges
  Depth range (m): 0 - 4.5
  Temperature range (°C): 2.279 - 2.279
  Nitrate (umol/L): 3.660 - 3.660
  Salinity (PPS): 33.515 - 33.515
  Oxygen (ml/l): 7.696 - 7.696
  Phosphate (umol/l): 0.700 - 0.700
  Silicate (umol/l): 4.428 - 4.428

Graphical representation

Depth range (m): 0 - 4.5
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Freshwater

Comments: Most populations occur in clear, cool, well-oxygenated creeks, small to medium rivers, and lakes. Individuals may move from streams into lakes or the sea to avoid high temperatures in summer. Some populations migrate between freshwater and saltwater habitats. Other populations (known as "coasters") live in lakes and migrate to streams to spawn, or they remain in the lake to spawn. Preferred water temperature is around 14-16 C; brook trout do poorly where water temperature exceeds 20 C for extended periods (see Sublette et al. 1990). Spawning occurs in cool water (usually less than 15 C) usually over gravel beds in shallow headwaters but also may occur in gravelly shallows of lakes if spring (groundwater) upwelling and moderate current or nearby surficial inflow (Quinn 1995) are present. Eggs are buried in nests in gravel. In Ontario, eggs were buried at 7-20 cm in bottom substrate (Snucins et al. 1992).

Depth: 15 - 27m.
From 15 to 27 meters.

Habitat: demersal.

Demersal; freshwater; brackish; marine; depth range 15 - 27 m. Occurs in clear, cool, well-oxygenated creeks, small to medium rivers, and lakes. ?Salters? run to the sea in the spring as stream temperatures rises, remain close to river mouths. May stay at sea for up to three months.

demersal; anadromous (Ref. 51243); freshwater; brackish; marine; depth range 15 - 27 m (Ref. 3899)

This species has been introduced or released in Dutch waters.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Some populations spawn and undergo considerable development in fresh water but also feed and develop to some extent in salt water (Hartel et al. 2002). These "salters" or "sea trout" may coexist with nonmigratory brook trout. The timing of seaward migration is variable but generally occurs in spring in northern latitudes (Naiman et al. 1987). Migrants spend a few days to 4 months in coastal seawater not far (usually less than 45 kilometers) from their natal stream (Mullan 1958, Smith and Saunders 1958, Bergin 1984, Naiman et al. 1987, Montgomery et al. 1990, Ryther 1997). Although sea-run populations often are referred to as being "anadromous," they are most accurately classified as "amphidromous" because they make regular feeding migrations to the sea while still undergoing significant freshwater growth (Collette and Klein-McPhee 2002).

Adults in some populations migrate seasonally between lakes and tributary streams. In the Great Lakes, these brook trout are known as "coasters." Some coasters remain permanently in lakes.

Movement can be extensive even within streams. For example, in the Kennebecasis River, New Brunswick, brook trout moved upstream 65-100 kilometers in spring after ice loss; summer movements were minimal; movements to spawning areas in fall were less than 10 kilometers, then the fish moved back downstream to wintering areas in the lower to middle reaches of the river (Curry et al. 2002).

Anadromous. Fish that ascend rivers to spawn, as salmon and hilsa do. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.

The food habits of brook trout vary according to their age and life history stage. As fry, or very young fish, brook trout feed primarily on immature stages of aquatic insects (Everhart, 1961). In general a brook trout's diet can be likened to a smorgasbord of organisms with prey ranging from mayflies to salamanders (Wittman, 2001). A brook trout will virtually eat anything its mouth will accommodate, including mostly many aquatic insect larvae such as caddisflies, mayflies, midges, and black flies. Other organisms consumed include worms, leeches, crustaceans, terrestrial insects, spiders, mollusks, a number of other fish species (cannibalism is limited to spawning time and spring), frogs, salamanders, snakes and even small mammals like voles (e.g. Microtus, Cleithrionomys), should they find one in the water (Scott and Crossman, 1985). As brook trout become larger their diet shifts more towards a piscovourus one (Everhart, 1961). Sea-run brook trout eat fish and intertebrates that are commonly found in marine environments (Scott and Crossman, 1985).

Animal Foods: mammals; amphibians; reptiles; fish; insects; terrestrial non-insect arthropods; mollusks; aquatic or marine worms; aquatic crustaceans

Primary Diet: carnivore (Piscivore , Insectivore )

Inhabits cold, well-oxygenated waters of rivers, lakes and reservoirs (Ref. 30578). Anadromous (Ref. 5951). Feeding effort in juveniles is directed toward sub-surface, invertebrate drift (Ref. 28091). It is preyed upon by eels, white perch, yellow perch, chain pickerel, eastern belted kingfisher and American merganser (Ref. 5951).

Comments: Feeds opportunistically on various invertebrate and vertebrate animals, including primarily terrestrial and aquatic insects and planktonic crustaceans. In estuarine and marine habitats, the diet includes various fishes and crustaceans (see Collette and Klein-McPhee 2002).

Wide range of organisms including worms, leeches, crustaceans, insects, mollusks, fishes, amphibians, and small mammals.

Salvelinus fontinalis (Brook trout (N=2)) is prey of:
Salvelinus fontinalis

Based on studies in:
USA: New York, Bridge Brook (Lake or pond)

This list may not be complete but is based on published studies.

Salvelinus fontinalis (Brook trout (N=2)) preys on:
Baetis bicaudatus
Cinygmula
Epeorus longimanus
Rhithrogena hageni
Ephemerella coloradensis
Ephemerella infrequens
Alloperla
Zapada haysi
Perlodidae
Simuliidae
Chironomidae
Rhyacophila acropedes
Rhyacophila valuma
Acari
emerging aquatic invertebrates
Auchenorrhyncha
Sternorrhyncha
Hymenoptera
Cottus bairdii
Eucalia inconstans
Phryganeidae
Ephemera
Baetidae
Trichoptera
Najna consiliorum
Araneidae
Poduridae
Psychodidae
Tanypodinae
Culicoides
Diptera
Coleoptera
Hirudinea
Cambarus propinquus
Limnephilidae
Ephemeroptera
Plectoptera
Odonata
Simulium
Hydropsychidae
Cambarus bartonii
Semotilus atromaculatus
Perca flavescens
Eupomotis gibbosus
Notropis cornutus
Catostomus commersoni
Rhagovelia
Anura
Notemigonus crysoleucas
Lepomis gibbosus
Ictalurus nebulosus
Actinopterygii
Salvelinus fontinalis
detritus
Terrestrial invertebrates
Aelosoma
Chauliodes
Chimarra atterima
Promoresia
Stenelmis crenata
Notropis heterolepis

Based on studies in:
USA: Colorado (River)
Canada: Ontario, Mad River (River)
Canada: Ontario (River)
USA: New York, Bridge Brook (Lake or pond)
USA: Maine, Martins (River)

This list may not be complete but is based on published studies.

Whirling Disease 3. Parasitic infestations (protozoa, worms, etc.)

Hysterothylacium Infection 8. Parasitic infestations (protozoa, worms, etc.)

Enteric Redmouth Disease. Bacterial diseases

Camallanus Infection 16. Parasitic infestations (protozoa, worms, etc.)

Adults in streams may defend small feeding territories that extend several body lengths in diameter (Grant et al. 1989). In experimental stream communities, Resetarits 1991 found that brook trout negatively affected both growth and survival of the salamander Gyrinophilus porphyriticus; the presence of Gyrinophilus had no affect on relative condition or fecundity of Salvelinus. Salvelinus and Gyrinophilus affected the growth of the two-lined salamander Eurycea and the crayfish Cambarus bartonii. Salvelinus caused Cambarus and Eurycea to alter their activity levels and habitat; Eurycea and Cambarus were able to avoid predation by Salvelinus and Gyrinophilus but at a significant cost to growth.

Comments: Most feeding in early morning and evening (Sublette et al. 1990).

Courtship begins with a male attempting to drive a female toward suitable spawning gravel. A receptive female chooses a spot and digs a redd. While the female is digging, the male continues courtship activity, darting alongside the female and quivering, swimming over and under her and rubbing her with his fins; most of the time however, is spent driving off other males. When the redd is completed, the pair enter the nest and deposit eggs and milt. After spawning the female covers the eggs by sweeping small pebbles at the downstream edge of the redd upstream. Once the eggs are completely covered, she moves to the upstream end of the redd and begins digging a new redd (Ref. 27547).

Average lifespan

Status: wild: 24.0 years.

Average lifespan

Sex: female

Status: wild: 16.0 years.

Average lifespan

Sex: male

Status: wild: 16.0 years.

Average lifespan

Status: wild: 8.0 years.

Maximum longevity: 24 years (wild) Observations: Environmental factors impact greatly on the lifespan of these animals (Das 1994).

Usually only a single male is able to fertilize the eggs that a female lays in a redd, but occasionally more than one male is able to do so. Usually the largest males are the most successful breeders.

Mating System: monogamous ; polyandrous

Brook trout spawn in late summer or autumn depending on the latitude and temperature (Scott and Crossman, 1985). The type of area required for brook trout spawning is one that offers loose, clean gravel in shallow riffles or shoreline area with an excellent supply of upwelling, oxygen-rich water (LaConte, 1997). Mature fish have been known to travel many miles upstream to reach adequate spawning grounds (Scott and Crossman, 1985). Females are able to detect upwelling springs or other areas of ground-water flow, which make for excellent spawning grounds. Brook trout reach maturity on an average at the age of two and spawn every year, although their size at first maturity depends on growth rate and the productivity of thier habitat (Everhart, 1961). Males often outnumber females at the spawning site, but only rarely is more than one male able to fertilize the eggs in a particular redd (Scott and Crossman, 1985; Blanchfield et al., 2003). The females clear away debris and silt with rapid fanning of her caudal fin while on her side, creating a redd (Scott and Crossman, 1985). The redd is where the eggs will be deposited and fertilized after the males compete for spawning right to the female (Scott and Crossman, 1985). The redd actually resembles a pit that is 4-12 inches in depth (Everhart, 1961). To gain the spawning right of the female the males compete for position by nipping and displaying themselves to the competitor males (Mills, 1971). When spawning is actually taking place the male takes a position to hold the female against the bottom of the redd and both of the fish vibrate intensely while eggs and milt are simultaneously discharged (Scott and Crossman, 1985). Very shortly after this exchange takes place the female works to cover the fertilized eggs with gravel by digging slightly upstream and letting the current carry the gravel down to fill the redd (Everhart, 1961). The eggs are initially adhesive to prevent them from washing away so they are able to incubate within the gravel (Scott and Crossman, 1985). The total time of incubation depends on factors such as temperature and oxygen (Scott and Crossman, 1985). After hatch the fry remain in the gravel until the yolk sac is absorbed then the fry swim up out of the gravel to begin the next stage of their life (Scott and Crossman, 1985).

Breeding interval: Brook trout breed once per year

Breeding season: Spawning occurs in late summer or autumn

Average age at sexual or reproductive maturity (female): 2 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Average age at sexual or reproductive maturity (male)

Sex: male: 730 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 730 days.

Spawning occurs in late summer (in north) or fall (October-November in many areas). Eggs hatch in 47 days at 10 C, in 165 days at 2.8 C. In Ontario, alevin emergence occurred over a 71-day period, coinciding with the spring thaw and an episodic pH depression (Snucins et al. 1992). Sexually mature in 2-3 years (also reported as first year for males, 2nd year for females). Only small percentages of returning migrants actually spawn; post-spawning mortality generally is low (Stearley 1992). In dense, small-stream populations, few live more than 3 years, whereas some live 9-10 years in large rivers and lakes in the northern part of the range (Behnke 2002).

Nest built in gravel by female, while being courted by male. After spawning, female covers the eggs with small pebbles.

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 29 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 29
Species: 32
Species With Barcodes: 1

There are many extensive conservation efforts directed towards brook trout, especially naturally reproducing brook trout populations. This is because in many northeastern states and Canada brook trout, the only native stream dwelling trout in many of these places, are very susceptible to urbanization and deforestation and its effects on the surrounding aquatic ecosystems. Ohio for example has only two naturally reproducing populations of brook trout left and breeds these populations in hatcheries then placing them in other suitable habitats to reestablish these populations (LaConte, 1997). Many other states and areas in Canada are performing similar projects to preserve this treasured and threatened natural resource.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Comments: 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 damge 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).

Not Evaluated

Management Requirements: See Thompson and Rahel (1996) for information on a depletion-removal electrofishing protocol that significantly reduced populations and recruitment but did not totally eradicate brook trout in streams managed for Colorado River cutthroat trout.

As a gamefish the brook trout is very highly sought after and one of the most popular, especially in north eastern North America (Scott and Crossman, 1985). The brook trout can be caught by fishing with artificial flies, spin casting, or with live bait (Scott and Crossman, 1985). Brook trout and their vastly popular sport fishing bring to a community related recreational activities such as camping, boating, and the need for gear, guides and transportation, all of which provide positive economic opportunities (Hubbs and Lagler, 1949). Brook trout have been raised in hatcheries and distributed world wide in hope of creating the above mentioned opportunities in places where they do not natively occur or to reestablish and strengthen native populations (Scott and Crossman, 1985).

Positive Impacts: food ; ecotourism

fisheries: minor commercial; aquaculture: commercial; gamefish: yes; aquarium: public aquariums

Comments: Has been used in carcinogen testing (Metcalfe 1989).

Species Impact: Introduced populations of brook trout have contributed to the decline of native fishes (e.g., rare forms of cutthroat trout in the Rocky Mountains, bull trout in Columbia River basin), amphibians, and invertebrates in cold streams and lakes in western North America (see Adams et al. 2002). Prevention of further invasion has become a major concern (Adams et al. 2002).

Comments: 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).