Brook trout

Brook trout

Overview
The brook trout, Salvelinus fontinalis, (sometimes called the eastern brook trout) is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the salmon
Salmonidae
Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...

 family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...

 population in Lake Superior
Lake Superior
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...

 are known as coaster trout or, simply, as coasters. Though commonly called a trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

, the brook trout is actually a char
Salvelinus
Salvelinus is a genus of salmonid fish often called char or charr; some species are called "trout". Salvelinus is a member of the Salmoninae subfamily of the Salmonidae family. Charr may be identified by light cream pink or red spots over a darker body. Scales tend to be small, with 115-200 along...

, along with lake trout
Lake trout
Lake trout is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char , touladi, togue, and grey trout. In Lake Superior, they can also be variously known as siscowet, paperbellies and leans...

, bull trout
Bull trout
The bull trout, Salvelinus confluentus, is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden" , but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S....

, Dolly Varden
Dolly Varden trout
The Dolly Varden trout, Salvelinus malma malma, is a subspecies of anadromous fish in the salmon family, and is technically a char. Although many of the fish are anadromous, the fish also exists in landlocked waters.- Range :The subspecies S. m...

 and the Arctic char
Arctic char
Arctic char or Arctic charr is both a freshwater and saltwater fish in the Salmonidae family, native to Arctic, sub-Arctic and alpine lakes and coastal waters. No other freshwater fish is found as far north. It is the only species of fish in Lake Hazen, on Ellesmere Island in the Canadian Arctic...

.

The term fontinalis comes from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 fontīnālis (of or from a spring or fountain).

The brook trout is native to small streams, creeks, lakes, and spring ponds.
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Encyclopedia
The brook trout, Salvelinus fontinalis, (sometimes called the eastern brook trout) is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the salmon
Salmonidae
Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...

 family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...

 population in Lake Superior
Lake Superior
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...

 are known as coaster trout or, simply, as coasters. Though commonly called a trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

, the brook trout is actually a char
Salvelinus
Salvelinus is a genus of salmonid fish often called char or charr; some species are called "trout". Salvelinus is a member of the Salmoninae subfamily of the Salmonidae family. Charr may be identified by light cream pink or red spots over a darker body. Scales tend to be small, with 115-200 along...

, along with lake trout
Lake trout
Lake trout is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char , touladi, togue, and grey trout. In Lake Superior, they can also be variously known as siscowet, paperbellies and leans...

, bull trout
Bull trout
The bull trout, Salvelinus confluentus, is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden" , but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S....

, Dolly Varden
Dolly Varden trout
The Dolly Varden trout, Salvelinus malma malma, is a subspecies of anadromous fish in the salmon family, and is technically a char. Although many of the fish are anadromous, the fish also exists in landlocked waters.- Range :The subspecies S. m...

 and the Arctic char
Arctic char
Arctic char or Arctic charr is both a freshwater and saltwater fish in the Salmonidae family, native to Arctic, sub-Arctic and alpine lakes and coastal waters. No other freshwater fish is found as far north. It is the only species of fish in Lake Hazen, on Ellesmere Island in the Canadian Arctic...

.

The term fontinalis comes from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 fontīnālis (of or from a spring or fountain).

Habitats and range


The brook trout is native to small streams, creeks, lakes, and spring ponds. Some brook trout, referred to as sea-run brook trout, are anadromous
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...

. It is native to a wide area of eastern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 but increasingly confined to higher elevations southward in the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...

 to northern Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 from the Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

 basin east, the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

Saint Lawrence
Saint Lawrence River
The Saint Lawrence is a large river flowing approximately from southwest to northeast in the middle latitudes of North America, connecting the Great Lakes with the Atlantic Ocean. It is the primary drainage conveyor of the Great Lakes Basin...

 system, and the upper Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 drainage as far west as eastern Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...

.

Typical pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 range
: 5 to 7.5
Unusual pH recordings: 3.5, 9.8.
Typical temperature range: 34 to 72°F (1 to 22°C)

Description


Colouration: green to brown basic colouration with a distinctive marbled pattern (called vermiculations) of lighter shades across the flanks and back and extending at least to the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

, and often to the tail. There is a distinctive sprinkling of red dots, surrounded by blue haloes, along the flank. The belly and lower fins are reddish in color, the latter with white leading edges. Often the belly, particularly of the males, becomes very red or orange when the fish are spawning. The species reaches a maximum recorded length of 86 cm (33 in) and a maximum recorded weight of 6.6 kg (14.5 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

). It can reach at least seven years of age, with reports of 15-year-old specimens observed in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 habitats to which the species has been introduced.
Typical length: 25 to 65 cm (10 to 26 in). Typical weight: 0.3 to 3 kg (11 oz to 7 lb).

Environmental requirements


S. fontinalis prefers clear waters of high purity and a narrow pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 range in lakes, rivers, and streams, being sensitive to poor oxygenation, pollution, and changes in pH caused by environmental effects such as acid rain
Acid rain
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions . It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of carbon dioxide, sulfur dioxide and nitrogen...

. Its diverse diet includes crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s and other amphibians, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, molluscs, smaller fish, invertebrates, and even small aquatic mammals such as vole
Vole
A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars . There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America...

s. It provides food for seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...

s and suffers attack by lamprey
Lamprey
Lampreys are a family of jawless fish, whose adults are characterized by a toothed, funnel-like sucking mouth. Translated from an admixture of Latin and Greek, lamprey means stone lickers...

s. The brook trout is a short-lived species, rarely surviving beyond four or five years in the wild.

Individuals normally spend their entire life in fresh water
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

, but some—colloquially called "salters" or "sea run"—may spend up to three months at sea in the spring, not straying more than a few kilometres from the river mouth. The fish return upstream to spawn in the late summer or autumn. The female constructs a depression in a location in the stream bed
Stream bed
A stream bed is the channel bottom of a stream, river or creek; the physical confine of the normal water flow. The lateral confines or channel margins, during all but flood stage, are known as the stream banks or river banks. In fact, a flood occurs when a stream overflows its banks and flows onto...

, sometimes referred to as a "redd", where groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

 percolates upward through the gravel. One or more males approaches the female, fertilizing the eggs as the female expresses them. The eggs are slightly denser than water. The female then buries the eggs in a small gravel mound. The eggs hatch in 95 to 100 days.

A potamodromous population of brook trout native to Lake Superior, which run into inflowing rivers to spawn, are called "coasters". Coasters tend to be larger than most other populations of brook trout, often reaching 2 to 3 kg in size. Many coaster populations have been severely damaged by overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....

 and by habitat alterations, especially by the construction of hydro-electric power dams, on their inflowing streams. In Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

 and Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, efforts are under way to restore and recover coaster populations.

Angling and commercial use




The brook trout is a popular game fish with anglers
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

, particularly fly fishermen
Fly fishing
Fly fishing is an angling method in which an artificial 'fly' is used to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. Casting a nearly weightless fly or 'lure' requires casting techniques significantly different from other forms of casting...

. Today, many anglers practice catch-and-release
Catch and release
Catch and release is a practice within recreational fishing intended as a technique of conservation. After capture, the fish are unhooked and returned to the water before experiencing serious exhaustion or injury...

 tactics to preserve remaining brook trout populations, and organizations such as Trout Unlimited
Trout Unlimited
Trout Unlimited is an international non-profit organization dedicated to the conservation of freshwater streams, rivers, and associated upland habitats for trout, salmon, other aquatic species, and people. Often contracted as "TU," the organization began in 1959 in Michigan...

 have been in the forefront of efforts to institute air and water quality standards sufficient to protect the brook trout. Revenues derived from the sale of fishing licenses have been used to restore many sections of creeks and streams to brook trout habitat. Brook trout are also commercially raised in large numbers for food production, being sold for human consumption in both fresh and smoked forms. Because of its dependence on pure water and a variety of aquatic and insect life forms, the brook trout is also used for scientific experimentation in assessing the effects of pollution.

Partially as a result of its popularity as a game fish
Game fish
Game fish are fish pursued for sport by recreational anglers. They can be freshwater or marine fish. Game fish can be eaten after being caught, though increasingly anglers practise catch and release to improve fish populations. Some game fish are also targeted commercially, particularly...

, the brook trout has been introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 in some areas to which it was not originally native, and has become established widely throughout the world. In some parts of the world, the brook trout has had a harmful effect on native species, and is a potential pest.

Hybrids


Brook trout can sometimes hybridise with other species and both natural and artificial hybrids are known. Native populations of bull trout
Bull trout
The bull trout, Salvelinus confluentus, is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden" , but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S....

 (S. confluentus) are in danger of hybridization with introduced brook trout in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...

.

Tiger trout


One such intergeneric hybrid, between the brook trout and the brown trout
Brown trout
The brown trout and the sea trout are fish of the same species....

 (genus Salmo
Salmo
Salmo is a genus of fish in the salmon family that includes the familiar species Atlantic salmon and brown trout . The natural distribution of the genus is chiefly European. Only the range of the Atlantic salmon extends to northern North America...

) is the tiger trout
Tiger trout
The tiger trout is a sterile, intergeneric hybrid of the brown trout and the brook trout . The name derives from the pronounced vermiculations, evoking the stripes of a tiger. It is a rare phenomenon in the wild, with the brook trout having 84 chromosomes and the brown trout 80...

. Tiger trout occur very rarely naturally but are sometimes artificially propagated. Such crosses are almost always reproductively sterile
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...

. They are popular with many fish stocking programs because they can grow quickly, and may help keep rough fish populations in check due to their highly piscivorous (fish-eating) nature.

Splake


A less frequent natural hybrid is the splake
Splake
The splake is a hybrid of two fish species resulting from the crossing of a male brook trout and a female lake trout...

, a hybrid between the brook trout and lake trout
Lake trout
Lake trout is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char , touladi, togue, and grey trout. In Lake Superior, they can also be variously known as siscowet, paperbellies and leans...

. Although uncommon in nature, some jurisdictions artificially propagate splake in substantial numbers for planting into brook trout or lake trout habitats. An example would be in Ontario, where both F1
F1 hybrid
F1 hybrid is a term used in genetics and selective breeding. F1 stands for Filial 1, the first filial generation seeds/plants or animal offspring resulting from a cross mating of distinctly different parental types....

 splake and a fish known as the lake trout backcross have been planted for several years. The backcross is the result of an F1 splake male being crossed with a female lake trout (i.e., 75% lake trout and 25% brook trout).

Although splake were first described in 1880, Ontario began experimenting with the hybrids in the 1960s in an effort to replace collapsed lake trout stocks in the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

. Due to mediocre results, the experiment never really progressed beyond Georgian Bay
Georgian Bay
Georgian Bay is a large bay of Lake Huron, located entirely within Ontario, Canada...

. The theory was that splake would grow more quickly and mature sooner than lake trout with the hope that they would be able to reproduce before being attacked by the invasive
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 sea lamprey
Sea lamprey
The sea lamprey is a parasitic lamprey found on the Atlantic coasts of Europe and North America, in the western Mediterranean Sea, and in the Great Lakes. It is brown, gray, or black on its back and white or gray on the underside and can grow up to 90 cm long. Sea lampreys prey on a wide...

. Unfortunately, although splake are relatively unusual among hybrids in that they are fertile, fertility in nature is behaviourally problematic—very few natural progeny are produced by introduced splake populations.

After some experimentation in the late 1970s, stocking in the Great Lakes and, especially, in Georgian Bay, was converted entirely to the so-called lake trout backcross in the early 1980s. Although the backcross program did succeed in creating some localised angling opportunities, it never achieved any degree of success in terms of natural reproduction—the backcross was only marginally better at reproducing than was the F1 splake. The F1 splake has proved to be a success, however, in providing angling opportunities in smaller lakes and most of the planting of splake in Ontario now goes to those situations. There are two general cases. In the first case, former brook trout waters which have become infested with spiny-rayed fish to the point where they no longer produce brook trout are stocked with splake. The splake grow more quickly than do wild-strain brook trout and become piscivorous at a younger age and, hence, are more tolerant of competitors than are brook trout. In the second case, relatively small lake trout lakes that experienced poor recruitment
Recruitment
Recruitment refers to the process of attracting, screening, and selecting qualified people for a job. For some components of the recruitment process, mid- and large-size organizations often retain professional recruiters or outsource some of the process to recruitment agencies.The recruitment...

 due to insufficient deep-water juvenile lake trout habitat will support fairly good splake fisheries since splake are less dependent on extreme deep water than are the lake trout and they grow more quickly, providing a better return to anglers. In both cases, due to the behavioural sterility of splake, all such fisheries are entirely dependent on artificial propagation.

Human-caused habitat destruction


Brook-trout populations depend on cold, clear, well-oxygenated water of high purity. As early as the late 19th century, native brook trout in North America became extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...

 from many watercourses as land development, forest clear-cutting, and industrialization took hold. Streams and creeks that were polluted, dammed, or silted up often became too warm to hold native brook trout, and were colonized by transplanted smallmouth bass
Smallmouth bass
The smallmouth bass is a species of freshwater fish in the sunfish family of the order Perciformes. It is the type species of its genus...

 and perch
Perch
Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...

 or other introduced salmonids such as brown
Brown trout
The brown trout and the sea trout are fish of the same species....

 and rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

. The brown trout, a species not native to North America, has replaced the brook trout in much of the brook trout's native water. Brook trout populations, if already stressed by overharvest or by temperature, are very susceptible to damage by the introduction of exogenous species. Many lacustrine
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 populations of brook trout have been extirpated by the introduction of other species, particularly percids
Percidae
The Percidae are a family of perciform fish found in fresh and brackish waters of the Northern Hemisphere. The family contains about 200 species in ten genera...

 but sometimes other spiny-rayed fishes
Perciformes
The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...

.

In addition to chemical pollution and algae growth caused by runoff containing chemicals and fertilizers, air pollution has also been a significant factor in the disappearance of brook trout from their native habitats. In the United States, acid rain caused by air pollution has resulted in pH levels too low to sustain brook trout in all but the highest headwaters of some Appalachian streams and creeks. Brook trout populations across large parts of eastern Canada have been similarly challenged; a subspecies known as the aurora trout
Aurora trout
The aurora trout, Salvelinus fontinalis timagamiensis, is a variant or subspecies of the brook trout native to two lakes in the Temagami District of Ontario, Canada. The existence of the fish was brought to the attention of the angling world by four American anglers who were taken by Archie King of...

was extirpated from the wild by the effects of acid rain.

Today, in many parts of the range, efforts are underway to restore brook trout to those waters that once held native populations, stocking other trout species only in habitats that can no longer be recovered sufficiently to sustain brook trout populations.

Records


The current brook trout world angling record was caught by Dr. W. J. Cook on the Nipigon River, Ontario, in July 1915. The 31 inch trout weighed only 14.5 lbs because, at the time of weighing, it was badly decomposed after 21 days in the bush without refrigeration. This is the longest-standing angling world record. A 29 inch brook trout, caught in October 2006 in Manitoba, is not eligible for record status since it was released alive.