Bull trout
Encyclopedia
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
" (S. malma), but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S. Endangered Species Act
.
, including Yukon
, British Columbia
, Washington, Oregon
, Idaho
, western Montana
, as well as the Jarbidge River
of northern Nevada
. A population of bull trout exists east of the Continental Divide
in Alberta
, where the bull trout is the provincial fish. The historical range of bull trout also included northern California
, but they are likely extirpated
.
(S. fontinalis) by the absence of distinct spots on the dorsal fin
, as well as yellow, orange, or salmon-colored spots on the back as opposed to red spots with blue haloes on the brook trout. Bull trout lack the deeply forked tail fin of lake trout
(S. namaycush, another char).
beds, deep pools, complex cover such as snag
s and cut banks, and large systems of interconnected waterways to accommodate spawning migrations. Thus, they favor the deep pools of cold lakes and large rivers, as well as high, cold mountain headwaters. Bull trout may be anadromous in coastal rivers, and individual bull trout have been found to have migrated from one coastal river to another via the ocean.
Young bull trout feed on zooplankton
and zoobenthos, especially chironomids. As they grow larger, they begin to feed heavily upon other fish. In coastal Washington state, some of the southernmost populations of bull trout feed heavily on salmon
eggs and fry, as well as fish.
throughout their range in the contiguous United States
. Bull trout are used as a management indicator species for several national forests, including Boise National Forest
and Sawtooth National Forest
(Sawtooth National Recreation Area
). Bull trout reproduction requires cold water and very low amounts of silt
, both of which are negatively impacted by road building and logging. Additionally, the bull trout's need to migrate throughout river systems may be hindered by impassible fish barriers such as dams.
Bull trout populations are also in danger from hybridization with non-native brook trout
.
They are a prized game fish
in Northern Canada
. Indeed, the fish was once maligned out of fear that they threatened populations of other native species more prized by anglers.
. This was likely due to over-lapping ranges and similar appearances among members of the two species.
The first recorded use of the name "Dolly Varden" for a fish species was applied to members of S. confluentus caught in the McCloud River
in northern California
in the early 1870s. In his book, Inland Fishes of California, Peter Moyle recounts a letter sent to him on March 24, 1974 from Mrs. Valerie Masson Gomez:
In 1874, Livingston Stone, a naturalist working for the U.S. government wrote of this fish:
It is currently unknown whether the name "Dolly Varden" was later applied to S. m. malma because of its similar appearance to S. confluentus; the two may have even been believed to be the same species. The name "Dolly Varden" may have also been given to S. m. malma independent of the McCloud River fish.
Ironically, it appears that the original "Dolly Varden" trout (i.e., S. confluentus) likely became locally extinct in the McCloud River in the 1970s, although reports continue of its being caught. Other fish species, typically introduced trout, will out-compete S. confluentus, and can interbreed resulting in sterile hybrids. An attempt to re-introduce S. confluentus to the McCloud was unsuccessful, and no additional attempts are expected.
, and S. m. miyabei, found on the island of Hokkaidō
in Japan
.
The name has also been applied to S. alpinus
, today more commonly known as Arctic char.
and other rivers in Scotland
and North East England
. Victorian anglers and others classified these as a separate race, but today they are biologically classified along with all other UK brown and sea-trout as Salmo trutta. This does not deny that populations of S. trutta can differ appreciably in habits, size and appearance from place to place, or indeed in the same river or lake.
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...
of the family Salmonidae
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...
native to northwestern 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...
. Historically, S. confluentus has been known as the "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...
" (S. malma), but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S. Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
.
Range
S. confluentus is found in the cold, clear waters of the high mountains and coastal rivers of northwestern North AmericaNorth 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...
, including Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Washington, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, western Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, as well as the Jarbidge River
Jarbidge River
The Jarbidge River is a , high altitude river in northern Nevada and southwest Idaho in the United States. The Jarbidge originates as two main forks in the Jarbidge Mountains of northeastern Nevada and then flows through basalt and rhyolite canyons on the high plateau of the Owyhee Desert before...
of northern Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
. A population of bull trout exists east of the Continental Divide
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...
in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, where the bull trout is the provincial fish. The historical range of bull trout also included northern 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...
, but they are likely 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...
.
Description
Like other species of char, the fins of bull trout have white leading edges. Its head and mouth are unusually large for salmonids, giving it its name. Bull trout have been recorded measuring up to 103 centimetres (41 in) in length and weighing 14.5 kilograms (32 lb). Bull trout may be either migratory, moving throughout large river systems, lakes, and the ocean, or they may be resident, remaining in the same stream their entire lives. Migratory bull trout are typically much larger than resident bull trout, which rarely exceed 2 kilograms (4 lb). Bull trout can be differentiated from brook troutBrook trout
The brook trout, Salvelinus fontinalis, is a species of fish in the salmon family of order Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous population in Lake Superior are known as coaster trout or, simply, as coasters...
(S. fontinalis) by the absence of distinct spots on 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...
, as well as yellow, orange, or salmon-colored spots on the back as opposed to red spots with blue haloes on the brook trout. Bull trout lack the deeply forked tail fin of 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...
(S. namaycush, another char).
Habitat and behavior
Bull trout have exacting habitat demands, requiring water temperatures generally below 55 °F (13 °C), clean gravelGravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
beds, deep pools, complex cover such as snag
Snag
In forest ecology, a snag refers to a standing, partly or completely dead tree, often missing a top or most of the smaller branches. In freshwater ecology it refers to trees, branches, and other pieces of naturally occurring wood found sunken in rivers and streams; it is also known as coarse woody...
s and cut banks, and large systems of interconnected waterways to accommodate spawning migrations. Thus, they favor the deep pools of cold lakes and large rivers, as well as high, cold mountain headwaters. Bull trout may be anadromous in coastal rivers, and individual bull trout have been found to have migrated from one coastal river to another via the ocean.
Young bull trout feed on zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
and zoobenthos, especially chironomids. As they grow larger, they begin to feed heavily upon other fish. In coastal Washington state, some of the southernmost populations of bull trout feed heavily on salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
eggs and fry, as well as fish.
Conservation
Bull trout are listed as a threatened species under the U.S. Endangered Species ActEndangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
throughout their range in the contiguous United States
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....
. Bull trout are used as a management indicator species for several national forests, including Boise National Forest
Boise National Forest
The Boise National Forest is a US national forest located north and east of the city of Boise, Idaho. It is about 2,612,000 acres in size, ranging in elevation from 2,600 to 9,800 feet . The mountainous landscape developed through uplifting, faulting, and stream cutting...
and Sawtooth National Forest
Sawtooth National Forest
Sawtooth National Forest is in Idaho and Utah was protected in 1905 by U.S. President Theodore Roosevelt as the Sawtooth Forest Reserve. Today the forest administers over 2.1 million acres of some of the most remote forestland in the lower 48 states, and there are over 1,000 lakes and 3,000...
(Sawtooth National Recreation Area
Sawtooth National Recreation Area
The Sawtooth National Recreation Area is a National Recreation Area located in central Idaho, within the Boise, Challis, and Sawtooth National Forests. The recreation area is managed by the U.S. Forest Service and includes the Sawtooth Wilderness...
). Bull trout reproduction requires cold water and very low amounts of silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
, both of which are negatively impacted by road building and logging. Additionally, the bull trout's need to migrate throughout river systems may be hindered by impassible fish barriers such as dams.
Bull trout populations are also in danger from hybridization with non-native brook trout
Brook trout
The brook trout, Salvelinus fontinalis, is a species of fish in the salmon family of order Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous population in Lake Superior are known as coaster trout or, simply, as coasters...
.
They are a prized 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...
in Northern Canada
Northern Canada
Northern Canada, colloquially the North, is the vast northernmost region of Canada variously defined by geography and politics. Politically, the term refers to the three territories of Canada: Yukon, Northwest Territories, and Nunavut...
. Indeed, the fish was once maligned out of fear that they threatened populations of other native species more prized by anglers.
"Dolly Varden" in California
There has been historic confusion between S. confluentus and Salvelinus malma malma, today commonly called the Dolly Varden troutDolly 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...
. This was likely due to over-lapping ranges and similar appearances among members of the two species.
The first recorded use of the name "Dolly Varden" for a fish species was applied to members of S. confluentus caught in the McCloud River
McCloud River
The McCloud River is a river that flows east of and parallel to the Sacramento River, long, in northern California in the United States. It drains a scenic mountainous area of the Cascade Range north of Redding...
in northern 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...
in the early 1870s. In his book, Inland Fishes of California, Peter Moyle recounts a letter sent to him on March 24, 1974 from Mrs. Valerie Masson Gomez:
My grandmother's family operated a summer resort at Upper Soda SpringsUpper Soda SpringsUpper Soda Springs is on the banks of the Sacramento River in Dunsmuir, California, USA. It consists of approximately ten acres of level ground on both sides of the River, the surrounding hillsides, and continues north along the eastern bank of the Sacramento River to the Dunsmuir City Park...
on the Sacramento RiverSacramento RiverThe Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...
just north of the present town of Dunsmuir, CaliforniaDunsmuir, CaliforniaDunsmuir is a city in Siskiyou County, California, United States. The population was 1,650 at the 2010 census, down from 1,923 at the 2000 census. It is currently a hub of tourism in Northern California as visitors enjoy fishing, skiing, climbing, or sight-seeing...
. She lived there all her life and related to us in her later years her story about the naming of the Dolly Varden trout. She said that some fishermen were standing on the lawn at Upper Soda Springs looking at a catch of the large trout from the McCloud RiverMcCloud RiverThe McCloud River is a river that flows east of and parallel to the Sacramento River, long, in northern California in the United States. It drains a scenic mountainous area of the Cascade Range north of Redding...
that were called 'calico trout' because of their spotted, colorful markings. They were saying that the trout should have a better name. My grandmother, then a young girl of 15 or 16, had been reading Charles DickensCharles DickensCharles John Huffam Dickens was an English novelist, generally considered the greatest of the Victorian period. Dickens enjoyed a wider popularity and fame than had any previous author during his lifetime, and he remains popular, having been responsible for some of English literature's most iconic...
' Barnaby RudgeBarnaby RudgeBarnaby Rudge: A Tale of the Riots of Eighty is a historical novel by British novelist Charles Dickens. Barnaby Rudge was one of two novels that Dickens published in his short-lived weekly serial Master Humphrey's Clock...
in which there appears a character named Dolly VardenDolly VardenDolly Varden may refer to:* Dolly Varden , a character in the novel Barnaby Rudge by Charles Dickens. The original usage.* Dolly Vardens , a group of Black women baseball players that comprised the first professional baseball team* Dolly Varden , a musical group from Chicago, Illinois* Dolly Varden...
; also the vogue in fashion for women at that time (middle 1870s) was called 'Dolly Varden,' a dress of sheer figured muslin worn over a bright-colored petticoat. My grandmother had just gotten a new dress in that style and the red-spotted trout reminded her of her printed dress. She suggested to the men looking down at the trout, 'Why not call them "Dolly Varden"?' They thought it a very appropriate name and the guests that summer returned to their homes (many in the San Francisco Bay area) calling the trout by this new name. David Starr JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
, while at Stanford UniversityStanford UniversityThe Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
, included an account of this naming of the Dolly Varden Trout in one of his books.
In 1874, Livingston Stone, a naturalist working for the U.S. government wrote of this fish:
Also called at (Upper) Soda Springs the 'Varden' trout. … The handsomest trout, and, on the whole, having the most perfect form of all the trout we saw on the McCloud. Also, the only fish that had colored spots. This one was profusely spotted over most of the body with redish [sic?] golden spots. ... The local name at (Upper) Soda Springs is the Dolly Varden.
It is currently unknown whether the name "Dolly Varden" was later applied to S. m. malma because of its similar appearance to S. confluentus; the two may have even been believed to be the same species. The name "Dolly Varden" may have also been given to S. m. malma independent of the McCloud River fish.
Ironically, it appears that the original "Dolly Varden" trout (i.e., S. confluentus) likely became locally extinct in the McCloud River in the 1970s, although reports continue of its being caught. Other fish species, typically introduced trout, will out-compete S. confluentus, and can interbreed resulting in sterile hybrids. An attempt to re-introduce S. confluentus to the McCloud was unsuccessful, and no additional attempts are expected.
Other uses of "Dolly Varden"
The "Dolly Varden" name is also applied to the other subspecies of S. malma: S. m. krascheninnikovaSouthern Dolly Varden
The Southern Dolly Varden is a subspecies of anadromous fish in the salmon family....
, and S. m. miyabei, found on the island of Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
The name has also been applied to S. alpinus
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...
, today more commonly known as Arctic char.
"Bull trout" in Europe
The name "bull-trout" was also given in the past to some of the large sea-trout (Salmo trutta) that run the River TweedRiver Tweed
The River Tweed, or Tweed Water, is long and flows primarily through the Borders region of Great Britain. It rises on Tweedsmuir at Tweed's Well near where the Clyde, draining northwest, and the Annan draining south also rise. "Annan, Tweed and Clyde rise oot the ae hillside" as the Border saying...
and other rivers in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
and North East England
North East England
North East England is one of the nine official regions of England. It covers Northumberland, County Durham, Tyne and Wear, and Teesside . The only cities in the region are Durham, Newcastle upon Tyne and Sunderland...
. Victorian anglers and others classified these as a separate race, but today they are biologically classified along with all other UK brown and sea-trout as Salmo trutta. This does not deny that populations of S. trutta can differ appreciably in habits, size and appearance from place to place, or indeed in the same river or lake.