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Chasmistes cujus

Scientific Name:Chasmistes cujus
Common name:Cui-ui
Rank and Status   
Global Rank:G1 Native Status:Native
Subnational (State) Rank:S1 Endemic:Yes
US ESA Status:Listed endangered Sand Dunes:No
NNHP Tracking Status:At-Risk List Wetland:Yes
Other Agency Status Status Last Updated Status Comments
Bureau of Land Management - Nevada Sensitive BLM Nevada Sensitive Species List dated 2017-10-01
State of Nevada Protected Endangered Fish NAC 503.065.2
Nevada Wildlife Action Plan - 2012 Species of Conservation Priority
Nevada Wildlife Action Plan - 2005 Species of Conservation Priority
CCVI Score Moderately Vulnerable Conf. VH; Factors contributing to increased vulnerability are natural and anthropogenic barriers, and historical and physiological hydrological niche.
Distribution (NV Counties)

Status: Confident or certain

Summary Occurrence Data
Occurrence Count:1
Total Observed Area (hectares):Not Available
Maximum Known Elevation (m):Not available
Minimum Known Elevation (m):1170
Chasmistes cujus data at NatureServe
Chasmistes cujus photos and data at Encyclopedia of Life
Character Abstract
Identification Comments:
Subspecies Comments:
Food Habits:The cui-ui feeds mainly on bottom-oriented zooplankton and macroinvertebrates such as ostracods, CYCLOPS, and chironomid larvae and pupae (Scoppettone and Vinyard 1991). Cui-ui feed somewhat above the bottom in water 10-30 m deep. (Sigler and Sigler 1987).
Phenology Comments:
Reproduction Comments:
Migration Mobility:
Habitat Comments:Cui-ui prefer inshore areas of the lake with extensive shoals and shallow bars. They generally avoid deep-water areas and inshore areas with steep dropoffs (though Page and Burr [1991] described the habitat as "deep water"). Usually this is at less than 46 m (Sigler and Sigler 1987). The cui-ui spawns in the Truckee River over gravel beds in relatively shallow water (21-140 cm) where flow is rapid. When runs are disturbed by low water levels, they may spawn at the river mouth. Cui-ui may spawn in Pyramid Lake, but extreme alkalinity and elevated salinity preclude successful reproduction there (Scoppettone and Vinyard 1991). Newly emerged young remain a few days or weeks in the spawning stream.
Ecology comments:Most adult mortality probably occurs during spawning runs (Sigler et al. 1985). Direct predation by humans was a significant cause of mortality until the 1970s. In recent years white pelicans have become a significant source of mortality (Scoppettone and Vinyard 1991).
Version Date:
adult specimen
Photographer: Glenn Clemmer, Nevada Natural Heritage Program
Photo Date:
habitat, Pyramid Lake
Photographer: Glenn Clemmer, Nevada Natural Heritage Program
Photo Date: