Deepwater sculpin
Deepwater sculpin (male, total length 125 mm, from Lake Michigan 2009)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Scorpaeniformes
Family: Cottidae
Genus: Myoxocephalus
Species:
M. thompsonii
Binomial name
Myoxocephalus thompsonii
(Girard, 1851)
Synonyms
  • Triglopsis thompsonii Girard, 1851

The deepwater sculpin (Myoxocephalus thompsonii) is a species of freshwater fish in the family Cottidae of order Scorpaeniformes.[2][1] It is a glacial relict, native to a limited number of deep, cold lakes in Canada and the United States.[1][3][4]

The deepwater sculpin was first described in 1851 by Charles Frédéric Girard[2] under the name Triglopsis thompsonii.[5] The description was based on specimens obtained by Spencer Fullerton Baird for the Smithsonian Institution from the stomachs of Burbot caught by fishermen on Lake Ontario.[6] The name Triglopsis referred to its resemblance to the Piper gurnard.[7] The specific epithet honored fellow naturalist Rev. Zadock Thompson of Burlington, Vermont.[6]

The similarity between this species and the Fourhorn sculpin led to some taxonomic discussion. Some authors considered it a subspecies (Myoxocephalus quadricornis thompsonii), while other authors maintained it as a species within the same genus (Myoxocephalus thompsonii).[3] Mitochondrial DNA analysis was able to establish that the two species were distinct while providing additional support for the proposal that the deepwater sculpin evolved from the fourhorn sculpin during the early Pleistocene era.[3]

The deepwater sculpin is a small fish on average between 51–76 millimetres (2.0–3.0 in) in length[3] Its body is generally flattened in shape and tapers from the head to the tail.[3] It does not have true scales.[3] Spines are present on the body and fins.[3] The skin is mottled green, gray and brown on the back and whitish underneath.[3][8] The deepwater sculpin can be distinguished from other freshwater sculpins in its range by a distinct gap between the two dorsal fins.[5][3][8] It is most similar in appearance to the fourhorn sculpin, a fish found in salt and brackish water in the arctic but lacks the four bony spines found on the head of that species.[9]

The deepwater sculpin is found from the Gatineau through the Great Lakes, Manitoba, and Saskatchewan to the Great Slave and Great Bear Lakes. It is also found in Waterton Lake within Waterton Lakes National Park and Glacier National Park.[3][10] Within its range, it is limited to deep, well oxygenated lakes with ties to former Wisconsinan glacial lakes or the Champlain Sea.[4]

The deepwater sculpin inhabits the demersal zone.[2] It prefers water temperatures that remain less than 5 °C (41 °F).[3] In lakes in the southern part of its range, it has been observed only in deep water where the water temperature remains cold year round.[3]

The deepwater sculpin feeds primarily on small crustaceans[2] Mysis diluviana and Diporeia.[3] They will also take chironomid larvae.[3][8] Zooplankton are the likely food of the larval stage.[3]

Deepwater sculpin eggs hatch from November to August, peaking in March. Larvae are initially pelagic, staying in the water column above the reach of their adults. Beginning in July, larvae that have grown to 2 centimetres (0.79 in) go through metamorphosis and settle to the bottom.[8] Fish are thought to reach maturity at three years for females and two years for males.[3]

Deepwater sculpin are a significant food source for other fish including lake trout (Salvelinus namaycush) and burbot (Lota lota).[3][8] They are an intermediate host for the parasites Bothriocephalus cuspidatus, and Proteocephalus sp. which also are found in the crustaceans they eat and the fish species that prey on them.[8]

The deepwater sculpin is an indicator species for the health of the deepwater communities in the lakes where it occurs.[3] It is of special interest to those interested in zoogeography.[3][4]

The deepwater sculpin is classified as of Least Concern by the IUCN based on the apparent stability of the population.[1] In Canada, it is considered a species at risk under the Species at Risk Act. Threats include habitat loss, lake eutrophication, invasive species, and water pollution.[3]

References

  1. ^ a b c d NatureServe (2013). "Myoxocephalus thompsonii". IUCN Red List of Threatened Species. 2013: e.T202671A18233813. doi:10.2305/IUCN.UK.2013-1.RLTS.T202671A18233813.en. Retrieved 12 November 2021.
  2. ^ a b c d "Myoxocephalus thompsonii, Deepwater sculpin". www.fishbase.se. Retrieved 12 July 2022.
  3. ^ a b c d e f g h i j k l m n o p q r s t COSEWIC (2017). "COSEWIC assessment and status report on the Deepwater Sculpin Myoxocephalus thompsonii, Great Lakes-Upper St. Lawrence populations, Southern Hudson Bay-James Bay populations, Saskatchewan-Nelson River populations, Waterton Lake population, Western Hudson Bay populations and Western Arctic populations in Canada" (PDF). Ottawa: Committee on the Status of Endangered Wildlife in Canada. Retrieved 11 July 2022.
  4. ^ a b c Sheldon, T. A.; Mandrak, N. E.; Lovejoy, N. R. (February 2008). "Biogeography of the deepwater sculpin (Myoxocephalus thompsonii), a Nearctic glacial relict" (PDF). Canadian Journal of Zoology. 86 (2). University of Toronto: 108–115. doi:10.1139/Z07-125. Retrieved 12 July 2022. The absence of the species beyond Wisconsinan glacial lake and Champlain Sea boundaries indicates that dispersal of deepwater sculpin between lakes has most likely not occurred since the late stages of the glacial lake phase of the Wisconsinan glaciation.
  5. ^ a b Girard, Charles Frédéric (1850). "Contributions to the Natural History of the Fresh Water Fishes of North America, Volume 1". Smithsonian Institution. p. 9. Retrieved 12 July 2022. Finally, we have established the genus Triglopsis for an entirely new fish discovered by Prof. Baird in Lake Ontario. It comprehends as yet, only one species, the description of which will be found in Chapter V.
  6. ^ a b Girard, Charles Frédéric (January 1, 1851). "Proceedings of the Boston Society of Natural History". Boston Society of Natural History. pp. 18–19. Retrieved 12 July 2022.
  7. ^ Girard, Charles Frédéric (1850). "Contributions to the Natural History of the Fresh Water Fishes of North America, Volume 1". Smithsonian Institution. p. 64. Retrieved 12 July 2022.
  8. ^ a b c d e f "Deepwater Sculpin - Montana Field Guide". fieldguide.mt.gov. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Retrieved 12 July 2022.
  9. ^ Stewart, Kenneth; Watkinson, Douglas A. (2004). The freshwater fishes of Manitoba. Winnipeg, Manitoba Canada: University of Manitoba Press. p. 205. ISBN 0887556787.
  10. ^ Sheldon, Tom A. (2006). "Ecology and evolution of the deepwater sculpin (Myoxocephalus thompsonii): conservation of a glacial relict" (PDF). University of Manitoba. Retrieved 12 July 2022.

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