Pygmy Whitefish
Encyclopedia
The pygmy whitefish, Prosopium coulterii, is a freshwater whitefish
of the genus Prosopium
in the family Salmonidae
. Found in the mountain streams and lakes west of North America, it also has isolated populations in Lake Superior
and in Ekityki Lake
, Chukchi Peninsula
.
or "parrs", are present on the young of this species, and on adults in some Alaskan populations. Commonly ranging from 3 to 15.3 cm (1.2 to 6 in) in length, it is typically 12 centimetres (4.7 in) long, and reaches a maximum length of 28 centimetres (11 in). It is identified by its small size, and its large eye, which has a greater length than its blunt snout. Its dorsal fin
and pectoral fin are usually clear, and its tail is clear with a faint dark spot. Its anal fin and pelvic fin are plain whitish. It has large scales with only 56–70 on its lateral line
, fewer gill rakers, all characteristics that indicate a degree of differentiation from the other Prosopium
fishes. Because of this, it is considered an early offshoot, or basal
, species in its genus, an especially trout-like member of a genus considered the most trout-like and primitive whitefish group.
and Rosa Smith Eigenmann
in 1892, as Coregonus coulteri. they named the species after the prominent botanist John Merle Coulter
. Since its initial description as a Coregonus
, it has been placed in the genus Prosopium
of more primitive whitefishes. The members of this genus are distinguished from the other whitefishes by several characteristics, such as a single flap of skin over the nostril, rather than one; "parr marks"; a round body; and a small toothless mouth. The genus name Prosopium, meaning "mask" in Greek
, refers to the large bones in front of its eyes.
, with three other disjunct populations. One is in Lake Superior
, another is in southwestern Alaska, and the third is in the Ekityki Lake
, Chukchi Peninsula
, Russia. The pygmy whitefish's range probably was continuous until the late Pleistocene
. In the Rocky Mountains it is found in cold and rapid streams, and in cool lakes at depths of over 6 metres (19.7 ft). In Lake Superior it is found in cooler water, at depths of 18 to 89 m (59.1 to 292 ft).
e of insects, and crustacean
s. In Lake Superior, the amphipod Pontoporeia
and various other crustaceans, mostly ostracod
s, form 77 percent of the pygmy whitefish's diet. The burbot
, kingfisher
s, and tern
s, and pikes
have been recorded preying on the pygmy whitefish.
Freshwater whitefish
The freshwater whitefish are fish of the subfamily Coregoninae in the salmon family Salmonidae. Along with the freshwater whitefish, the Salmonidae includes the freshwater and anadromous trout and salmon species as well as graylings...
of the genus Prosopium
Prosopium
Prosopium is a genus of freshwater whitefishes found in North America and parts of eastern Russia. It contains three fairly widespread species: the round whitefish, the pygmy whitefish, and the mountain whitefish. The remaining species, the Bonneville cisco, the Bonneville whitefish, and the Bear...
in 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...
. Found in the mountain streams and lakes west of North America, it also has isolated populations 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...
and in Ekityki Lake
Ekityki Lake
The Ekityki Lake is a lake in Chukotka, in the Siberian Far East. It belongs to the Ekityki river basin and the Ekityki River flows through it....
, Chukchi Peninsula
Chukchi Peninsula
The Chukchi Peninsula, Chukotka Peninsula or Chukotski Peninsula , at about 66° N 172° W, is the northeastern extremity of Asia. Its eastern end is at Cape Dezhnev near the village of Uelen. It is bordered by the Chukchi Sea to the north, the Bering Sea to the south, and the Bering Strait to the...
.
Description
The pygmy whitefish is a small herring-like fish with a long and cylindrical body by comparison to other whitefishes. Silvery in colour, it has a brownish back, and a whitish belly. Black spots on the side called "parr marks", which are present on young troutTrout
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...
or "parrs", are present on the young of this species, and on adults in some Alaskan populations. Commonly ranging from 3 to 15.3 cm (1.2 to 6 in) in length, it is typically 12 centimetres (4.7 in) long, and reaches a maximum length of 28 centimetres (11 in). It is identified by its small size, and its large eye, which has a greater length than its blunt snout. Its 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 pectoral fin are usually clear, and its tail is clear with a faint dark spot. Its anal fin and pelvic fin are plain whitish. It has large scales with only 56–70 on its lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
, fewer gill rakers, all characteristics that indicate a degree of differentiation from the other Prosopium
Prosopium
Prosopium is a genus of freshwater whitefishes found in North America and parts of eastern Russia. It contains three fairly widespread species: the round whitefish, the pygmy whitefish, and the mountain whitefish. The remaining species, the Bonneville cisco, the Bonneville whitefish, and the Bear...
fishes. Because of this, it is considered an early offshoot, or basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
, species in its genus, an especially trout-like member of a genus considered the most trout-like and primitive whitefish group.
Taxonomy
The pygmy whitefish was first described by Carl H. EigenmannCarl H. Eigenmann
Carl H. Eigenmann was an ichthyologist who, along with his wife Rosa Smith Eigenmann, described many of the fishes of North America and South America for the first time....
and Rosa Smith Eigenmann
Rosa Smith Eigenmann
Rosa Smith Eigenmann was the first notable female ichthyologist; first publishing in her own right, she later collaborated with her husband Carl H. Eigenmann, and some 150 species of fish are today credited "Eigenmann & Eigenmann" as a result.She was born in Monmouth, Illinois, the last of nine...
in 1892, as Coregonus coulteri. they named the species after the prominent botanist John Merle Coulter
John Merle Coulter
John Merle Coulter, Ph. D. was an American botanist and educator, brother of Stanley Coulter, born at Ningpo, China. He received his education at Hanover College in Indiana. He served in the Rocky Mountains for two years as botanist to the United States Geological Survey...
. Since its initial description as a Coregonus
Coregonus
Coregonus is a diverse genus of fish in the salmon family . The type species is the common whitefish . The Coregonus species are known as whitefishes...
, it has been placed in the genus Prosopium
Prosopium
Prosopium is a genus of freshwater whitefishes found in North America and parts of eastern Russia. It contains three fairly widespread species: the round whitefish, the pygmy whitefish, and the mountain whitefish. The remaining species, the Bonneville cisco, the Bonneville whitefish, and the Bear...
of more primitive whitefishes. The members of this genus are distinguished from the other whitefishes by several characteristics, such as a single flap of skin over the nostril, rather than one; "parr marks"; a round body; and a small toothless mouth. The genus name Prosopium, meaning "mask" in Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
, refers to the large bones in front of its eyes.
Distribution
The pygmy whitefish is found mostly in the northern Rocky MountainsRocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
, with three other disjunct populations. One is 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...
, another is in southwestern Alaska, and the third is in the Ekityki Lake
Ekityki Lake
The Ekityki Lake is a lake in Chukotka, in the Siberian Far East. It belongs to the Ekityki river basin and the Ekityki River flows through it....
, Chukchi Peninsula
Chukchi Peninsula
The Chukchi Peninsula, Chukotka Peninsula or Chukotski Peninsula , at about 66° N 172° W, is the northeastern extremity of Asia. Its eastern end is at Cape Dezhnev near the village of Uelen. It is bordered by the Chukchi Sea to the north, the Bering Sea to the south, and the Bering Strait to the...
, Russia. The pygmy whitefish's range probably was continuous until the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
. In the Rocky Mountains it is found in cold and rapid streams, and in cool lakes at depths of over 6 metres (19.7 ft). In Lake Superior it is found in cooler water, at depths of 18 to 89 m (59.1 to 292 ft).
Ecology
In Lake Superior, the pygmy whitefish spawns during November and December at depths of 31 to 46 m (101.7 to 150.9 ft). Females lay an average of 362 orange eggs, with a diameter of 2.57 millimetre (0.101181102362205 in). Elsewhere, the pygmy whitefish migrates upstream to spawn, usually spawning in November or December in gravelly streams. Pygmy whitefish feed primarily on the aquatic larvaLarva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of insects, and 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. In Lake Superior, the amphipod Pontoporeia
Pontoporeia
Pontoporeia is a genus of fungi in the family Zopfiaceae....
and various other crustaceans, mostly ostracod
Ostracod
Ostracoda is a class of the Crustacea, sometimes known as the seed shrimp because of their appearance. Some 65,000 species have been identified, grouped into several orders....
s, form 77 percent of the pygmy whitefish's diet. The burbot
Burbot
The burbot is the only gadiform fish inhabiting freshwaters. It is also known as mariah, the lawyer, and eelpout. It is closely related to the marine common ling and the cusk...
, kingfisher
Kingfisher
Kingfishers are a group of small to medium sized brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species being found in the Old World and Australia...
s, and tern
Tern
Terns are seabirds in the family Sternidae, previously considered a subfamily of the gull family Laridae . They form a lineage with the gulls and skimmers which in turn is related to skuas and auks...
s, and pikes
Esox
Esox is a genus of freshwater fish, the only living genus in the family Esocidae — the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.The type species is E. lucius, the northern pike...
have been recorded preying on the pygmy whitefish.
Literature cited
- Alaska Natural Heritage Program (2005). "Pygmy Whitefish" Fishes Tracking List and Status Reports. Retrieved 10 February 2010.
- Behnke, Robert J. (2002). Trout and Salmon of North America. Free Press. ISBN 9780743222204.
- Becker, George C. (1983). Fishes of Wisconsin Madison, Wisconsin: University of Wisconsin Press. ISBN 0299087905
- Dickson, Tom (2008). The Great Minnesota Fish Book Minneapolis: University of Minnesota Press. ISBN 978-0-8166-5135-1
- Hubbs, Carl C.; Lagler, Karl F.; and Smith, Gerald R. (2004). Fishes of the Great Lakes Region revised ed. Ann Arbor: University of Michigan Press. ISBN 0-472-11371-2
- Mackay, W. C. (2000). "Status of the Pygmy Whitefish (Prosopium coulteri) in Alberta." Wildlife Status Report 27 Edmonton, Alberta: Alberta Environment, Fisheries and Wildlife Management Division, and Alberta Conservation Association. Retrieved 16 February 2010
- Page, Lawrence M., and Burr, Brooks M. (1991). A Field Guide to Freshwater Fishes Boston: Houghton Mifflin. ISBN 0-395-910910