The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)
IUCN 2008: T5439A15364219
Cottus extensus, Bear Lake Sculpin
Assessment by: NatureServe
View on www.iucnredlist.org
Citation: NatureServe. 2013. Cottus extensus. The IUCN Red List of Threatened Species 2013:
e.T5439A15364219. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Actinopterygii
Scorpaeniformes
Cottidae
Taxon Name: Cottus extensus Bailey & Bond, 1963
Common Name(s):
• English:
Bear Lake Sculpin
Assessment Information
Red List Category & Criteria:
Vulnerable D2 ver 3.1
Year Published:
2013
Date Assessed:
November 9, 2011
Justification:
This species is listed as Vulnerable because it occurs naturally in only one location and thus may be
vulnerable to events (e.g., introduction of non-native species) that could lead to major declines or
extirpation. Population size is very large.
Previously Published Red List Assessments
1996 – Vulnerable (VU)
1994 – Rare (R)
1990 – Rare (R)
1988 – Rare (R)
1986 – Rare (R)
Geographic Range
Range Description:
Endemic to Bear Lake, Utah and Idaho (Page and Burr 2011). Introduced in Flaming Gorge Reservoir,
Utah and Wyoming (Sigler and Sigler 1987), where apparently established.
Country Occurrence:
Native: United States
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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Distribution Map
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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Population
One population in Bear Lake.
Abundance varies widely from year to year; counting only those individuals more than 1 year old, total
estimated minimum population size over seven years varied from about 1.5 million to 5+ million
(Wurtsbaugh and Luecke 1998).
Trend over the past three generations is unknown but probably relatively stable or slowly declining.
Current Population Trend: Unknown
Habitat and Ecology (see Appendix for additional information)
This is a benthic species that occurs in a large lake, from shorelines to depths of 53 meters or more (Lee
et al. 1980). Usually it is on rocky bottoms at depths of 15 meters or more when not breeding. Spawning
occurs among rocks close to the shore. Eggs are deposited on underside of rocks or other material
(Simpson and Wallace 1982).
Systems: Freshwater
Use and Trade
This species is not utilized.
Threats (see Appendix for additional information)
Threats include habitat degradation and perhaps predation by introduced non-native species. Based on
historical massive die-offs of other fish species in large lakes (e.g., in the Great Lakes), this species may
be vulnerable to events that could lead to major declines or extirpation.
Conservation Actions (see Appendix for additional information)
Better information is needed on life history and reproductive biology. Bear Lake needs to be protected
from alterations that would be harmful or fatal to this species.
Credits
Assessor(s):
NatureServe
Reviewer(s):
Smith, K. & Darwall, W.R.T.
Facilitators(s) and
Compiler(s):
Hammerson, G.A. & Ormes, M.
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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Bibliography
IUCN. 2013. IUCN Red List of Threatened Species (ver. 2013.1). Available at: http://www.iucnredlist.org.
(Accessed: 12 June 2013).
Koster, W.J. 1936. The life history and ecology of the sculpins (Cottidae) in central New York. Ph.D. thesis,
Cornell University.
Koster, W.J. 1937. The food of the sculpin (Cottidae) in central New York. Transactions of the American
Fisheries Society 66: 374-382.
Lee, D.S., Gilbert, C.R., Hocutt, C.H., Jenkins, R.E., McAllister, D.E. and Stauffer, J.R. Jr. 1980. Atlas of
North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North
Carolina.
Nelson, J.S. 1984. Fishes of the world. John Wiley & Sons, New York, New York.
Nelson, J.S., Crossman, E.J., Espinosa-Perez, H., Findley, L.T., Gilbert, C.R., Lea, R.N. and Williams, J.D.
2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American
Fisheries Society, Bethesda, Maryland.
Page, L.M. and Burr, B.M. 1991. A field guide to freshwater fishes: North America north of Mexico.
Houghton Mifflin Company, Boston, Massachusetts.
Page, L.M. and Burr, B.M. 2011. Peterson field guide to freshwater fishes of North America north of
Mexico. Houghton Mifflin Harcourt, Boston, Massachusetts.
Robins, C.R., Bailey, R.M., Bond, C.E., Brooker, J.R., Lachner, E.A., Lea, R.N. and Scott, W.B. 1991.
Common and scientific names of fishes from the United States and Canada. American Fisheries Society.
Sigler, W.F. and Sigler, J.W. 1987. Fishes of the Great Basin: a natural history. University of Nevada Press,
Reno, Nevada.
Simpson, J. and Wallace, R. 1982. Fishes of Idaho. The University Press of Idaho, Moscow, Idaho.
Wurtsbaugh, W. and Luecke, C. 1998. Limnological relationships and population dynamics of fishes in
Bear Lake (Utah/Idaho). Final report to Utah Division of Wildlife Resources. Salt Lake City.
Citation
NatureServe. 2013. Cottus extensus. The IUCN Red List of Threatened Species 2013: e.T5439A15364219.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
For Images and External Links to Additional Information, please see the Red List website.
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
5. Wetlands (inland) -> 5.5. Wetlands (inland) - Permanent Freshwater
Lakes (over 8ha)
-
Suitable
Yes
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.1.
Unspecified species
Ongoing
Whole (>90%)
-
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Whole (>90%)
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
9. Pollution -> 9.3. Agricultural & forestry effluents ->
9.3.4. Type Unknown/Unrecorded
-
-
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
1. Land/water protection -> 1.1. Site/area protection
1. Land/water protection -> 1.2. Resource & habitat protection
2. Land/water management -> 2.1. Site/area management
2. Land/water management -> 2.3. Habitat & natural process restoration
4. Education & awareness -> 4.3. Awareness & communications
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
1. Research -> 1.3. Life history & ecology
Additional Data Fields
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
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Habitats and Ecology
Movement patterns: Not a Migrant
© The IUCN Red List of Threatened Species: Cottus extensus – published in 2013.
http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T5439A15364219.en
6
The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN
Red List Partners are: BirdLife International; Botanic Gardens Conservation International; Conservation
International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas
A&M University; Wildscreen; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™