2006 Green River Watershed Native Non-Game Fish Species Research: Phase II

Publication Information

Aaron Kern
Rob Keith
Publication Date: 2007-03
Tags: WLCI Agency Report, WLCI


Flannelmouth sucker (Catostomus latipinnis), bluehead sucker (Catostomus 
discobolus), and roundtail chub (Gila robusta), hereafter target species, are native to the 
Colorado River basin and have undergone declines in both abundance and distribution 
throughout their ranges.  Due to these declines, state and federal agencies have entered 
into a range-wide conservation agreement and strategy to ensure the persistence of these 
species in their native ranges (Utah Division of Wildlife Resources 2006) 
Weitzel (2002) reports that these three species were historically abundant in the 
Green River watershed of southwestern Wyoming.  However, populations have declined 
in Wyoming (Weitzel 2002) and throughout the Colorado River drainage (Bezzerides and 
Bestgen 2002).  The Wyoming Natural Diversity Database assigns bluehead sucker 
(BHS) the global ranking of G4 suggesting this species is abundant and globally secure, 
although it may be quite rare in portions of its range and should therefore be an object of 
long-term concern (Keinath et al. 2003).  Flannelmouth sucker (FMS) have been assigned 
the global ranking of G3/G4, which suggests its existence is uncertain.  It is uncommon 
but appears to be locally secure.  Roundtail chub (RTC) have been assigned the ranking 
of G3, which suggests its existence to be quite rare throughout its range or locally 
abundant and highly restricted.  Additionally, the Wyoming Game and Fish Department 
classifies these three species as NSS1 species, meaning that they are rare and their habitat 
is declining or vulnerable.  
Baxter and Simon (1970) and Wheeler (1997) represent the only drainage-wide 
fish surveys conducted in the Green River watershed of southwest Wyoming.  The recent 
surveys conducted by Wheeler (1997) show that from 1965 to 1995 the three species 
declined in the Wyoming portion of the Green River drainage at three spatial scales (site, 
stream, and sub-drainage).  In 1995, Wheeler documented BHS in the Hams Fork 
drainage, and RTC in the Hams Fork, Blacks Fork and Little Snake River drainages. In 
1995, FMS were documented throughout the Green River drainage downstream of 
Fontenelle Reservoir and in the Little Snake River drainage (Wheeler 1997).  In addition 
to these drainage-wide survey efforts, the Bitter Creek sub-drainage was surveyed in 
1993 (Carter and Hubert 1995) and the Big Sandy River sub-drainage was surveyed in 
the 1960’s and 1970’s (Miller 1978).   


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