Sturgeon chub

Sturgeon chub
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Macrhybopsis
Species: M. gelida
Binomial name
Macrhybopsis gelida
(Girard, 1856)

The sturgeon chub (Macrhybopsis gelida) is a species of ray-finned minnow fish in the Cyprinidae family. It is found only in the United States. It is a species of concern in the Charles M. Russell National Wildlife Refuge in Montana.[1]

Names and documentation

The type species was collected in the Milk River in Montana, and described by Charles Frédéric Girard in 1856.[2] Girard named it Gobio gelidus, but it was reclassified as Hybopsis gelidus in 1900 and Macrhybopsis gelidus in 1935.[2] A new classification of Hybopsis gelida was suggested in 1965.[2]

Description and habitat

The sturgeon chub is slender, streamlined fish with a long, flat snout.[3][4] The snout resembles that of a sturgeon, which gives the fish its name. Adults grow to be about 3 inches (7.6 cm) in length.[5] There is a small barbel near the corner of the mouth, and small pustules on the throat.[2] The scales on the sturgeon chub's back and sides have a small ridge-like projection known as a "keel". The purpose of the keel is not established, but may help the fish stabilize and orient itself in fast currents[3] or as a means of detecting currents.[5] The eyes are small and it does not see well.[6] The fish's color ranges from silvery-white on the belly to silvery sides, with a light-brown back.[4] The tail is deeply forked, with the lower lobe darker than the upper lobe.[4] The body fins are triangular,[7] slightly rounded,[2] and straight-edged (unlike the sicklefin chub).[8] The last dorsal fin ray extends beyond the first ray of the depressed fin.[8]

Little is known about its feeding habits,[7] although it does have teeth in its throat.[4] The body is covered with taste buds which help it locate food.[9] It lives in waters which are little populated by other small fish, but can be found associating with the flathead chub, sicklefin chub, and speckled chub.[4]

Sturgeon chub exhibits little sexual dimorphism, and neither sex exhibits color changes during breeding. However, the male does develop small tubercles behind the gills during breeding.[7] It lays eggs on gravel or clean sand to reproduce.[3] Breeding probably occurs in June.[10]

The habitat of the sturgeon chub is murky river bottoms in fast-flowing streams with gravel bottoms.[3] Its habitat extends over the Missouri River and its primary tributaries, the lower Mississippi River in the states of Mississippi and Louisiana, and some streams in northeastern Wyoming.[3] Increased silt and the construction of dams (which cause silt to settle and slow river currents) have destroyed extensive portions of its habitat.[3] It remains common in the middle Missouri River, but rare elsewhere.[8] The United States Fish and Wildlife Service (FWS) estimated in 2001 that it only inhabited about 59 percent of its former range.[11]

References

  1. ↑ U.S. Fish and Wildlife Service. Draft Comprehensive Conservation Plan and Environmental Impact Statement: Charles M. Russell National Wildlife Refuge and UL Bend National Wildlife Refuge, Montana. U.S. Department of the Interior. September 2010, p. 60. Accessed 2012-04-27.
  2. 1 2 3 4 5 Smith, Philip Wayne. The Fishes of Illinois. Chicago: University of Illinois Press, 2002, p. 78.
  3. 1 2 3 4 5 6 Marshall Cavendish Corporation. Endangered Wildlife and Plants of the World. New York: Marshall Cavendish, 2001, p. 267.
  4. 1 2 3 4 5 Pflieger, William L. and Smith, Pat. The Fishes of Missouri. Jefferson City, Mo.: Missouri Department of Conservation, 1997, p. 9.
  5. 1 2 Johnsgard, Paul A. The Nature of Nebraska: Ecology and Biodiversity. Lincoln, Neb.: University of Nebraska Press, 2005, p. 174.
  6. ↑ Marshall Cavendish Corporation, p. 267-268.
  7. 1 2 3 Marshall Cavendish Corporation, p. 268.
  8. 1 2 3 Page, Lawrence M. and Burr, Brooks. Peterson Field Guide to Freshwater Fishes of North America North of Mexico. Boston: Houghton Mifflin Harcourt, 2011, p. 104.
  9. ↑ Savage, Candace. Prairie: A Natural History. Vancouver, B.C.: Greystone Books, 2011, p. 180.
  10. ↑ Smith, p. 79.
  11. ↑ Stukel, E.D. "Sturgeon and Sicklefin Chubs." South Dakota Conservation Digest. May/June 2001, p. 25.

Further reading

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