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Pacifastacus gambelii

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA ARTHROPODA MALACOSTRACA DECAPODA ASTACIDAE

Scientific Name: Pacifastacus gambelii
Species Authority: (Girard, 1852)
Common Name/s:
English Pilose Crayfish

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor/s: Schuster, G.A., Taylor, C.A. & Cordeiro, J.
Reviewer/s: Collen, B. & Richman, N.
Contributor/s: Livingston, F., Livingston, F., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.
Justification:
Pacifastacus gambelii has been assessed as Least Concern.  This species is widespread across several states in the Pacific Northwest, and is considered to be abundant where it is found. Furthermore, it has been assessed as Currently Stable by the American Fisheries Society.  However it may be undergoing localised declines as a result of pollution and siltation that compromises the high quality environmental conditions this species requires. Additionally invasive species are thought to have caused declines in Montana.  Threats to the global population are currently unidentified; however its widespread distribution is likely to be a buffer against most threats.  Further research on current threats to this species and population size is recommended so that significant changes in the population can be identified.

Geographic Range [top]

Range Description: Pacifastacus gambelii is common and wideranging across the Pacific Northwest and Rocky Mountains. It is distributed along the Pacific slope and in the Missouri River drainage in California, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming, with a suspected introduction into California.
The pilose crayfish is widespread and often abundant in the Bear and River drainages.
Countries:
Native:
United States (California - Introduced, Idaho, Montana - Possibly Extinct, Nevada, Oregon, Utah, Washington, Wyoming)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The pilose crayfish is widespread and often abundant in the Bear and River drainages (Johnson 1986) and also abundant in Salt Creek.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Pacifastacus gambelii is found in lentic and lotic habitats and is likely to breed during the spring. This species is believed to be an opportunistic feeder that breeds in the springtime and has a home range estimated to be no more than 50 meters (Wyoming Game and Fish Department 2002). The pilose crayfish is belived to be intollerable of warmer waters or of the warmer water fish populations (Johnson 1986).
Systems: Freshwater

Threats [top]

Major Threat(s): Pacifastacus gambelii has been assessed as Currently Stable by the American Fisheries Society (Taylor et al. 2007). However, the government of Wyoming has stated that potential threats to this species include the requirement of high quality water coupled with a low tolerance for pollution and siltation. In addition, the sources of pollution and siltation are yet to be precisely identified (Wyoming Game and Fish Department 2002).
Pacifastacus gambelii is believed to be extirpated in Montana due to introduced species (Montana Natural Heritage Program 2008). Hubert (1988) believed that introduced species were having a negative affect on the pilose crayfish in the Snake and Bear River areas.

Conservation Actions [top]

Conservation Actions: Pacifastacus gambelii received protection under the federal Endangered Species Act of 1973 (ESA) and classified as species of concern by the Wyoming Game and Fish Department. The abundance of this species is largely unknown, and little life history information is available. In addition to this the sources of pollution and siltation are yet to be precisely identified (Wyoming Game and Fish Department 2002). Further research into the causes of potential threats are needed.

NatureServe G4G5
AFS Currently Stable (Taylor et al. 2007).
Citation: Schuster, G.A., Taylor, C.A. & Cordeiro, J. 2010. Pacifastacus gambelii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 18 April 2014.
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