2005 Green River Watershed Native Non-Game Fish Species Research: Phase II
Author(s):Publication Date: 2006-02
Tags: WLCI Agency Report, WLCI, Green River
Conservation efforts to protect and restore native fish species of the Colorado River basin
are underway (Utah Division of Wildlife Resource 2004a and 2004b). Flannelmouth sucker
(Catostomus latipinnus), bluehead sucker (Catostomus discobolus), and roundtail chub (Gila
robusta), hereafter target species, are three species native to the Colorado River basin that have
been targeted by these efforts.
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 in other areas 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 to be 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 subdrainage). 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 subdrainage was surveyed in the 1960’s and 1970’s (Miller 1978). Bluehead sucker and RTC were
not documented in the 1993 Bitter Creek survey, but FMS were documented from a site near the
Bitter Creek-Green River confluence (Carter and Hubert 1995).