endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Pacific versant in Oregon, Washington, Idaho, Montana, Nevada, Wyoming and possibly northeast California. Missouri drainage in Montana and Wyoming and Utah. Only extant member of its genus east of the North American continental divide (Hobbs, 1989; Rogers, 2005).
The pilose crayfish is widespread and often abundant in the Bear and River drainages.
Pigmented, eyes normal; rostrum with margins converging to indistinct acumen and with at least 3 pr lateral marginal spines, carinate; postorbital ridges without posterior spines or tubercles; dorsal surface of palm studded with minute tubercles and 2 conspicuous longitudinal clusters of setae.
Habitat Type: Freshwater
Comments: It 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).
Habitat and Ecology
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Home range probably does not exceed 50 m.
Comments: No data; probably opportunistic.
Comments: The pilose crayfish is widespread and often abundant in the Bear and River drainages (Johnson, 1986) and also abundant in Salt Creek.
Life History and Behavior
Comments: Data suggest most active after sundown, but sometimes move about stream bed in day hours.
Data suggest spring breeding.
National NatureServe Conservation Status
Rounded National Status Rank: N4 - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: This species is common and wideranging across the Pacific Northwest and Rocky Mountains. Population information is not known but it is abundant in some drainages. Some extirpations have occurred due to exotic crayfish introductions (Montana).
IUCN Red List Assessment
Red List Category
Red List Criteria
Degree of Threat: Unknown
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.
AFS Currently Stable (Taylor et al. 2007).
Relevance to Humans and Ecosystems
Comments: No known economic value.
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