BOARD00038 ‎(2)‎

• Board Meeting Date: 9/20/2006
• Description: WSP Section - San Juan River Recovery Implementation Program Document Revisions
• Board Meetings - Doc Type: Memo

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. Fish Fauna

Native Fish Fauna

Ichthyofaunal surveys of the San Juan basin prior to extensive European settlement were very
limited. These surveys documented the occurrence of at least eight native fish species (Table 1):
cutthroat trout, roundtail chub, Colorado pikeminnow, speckled dace, flannelmouth sucker,
bluehead sucker, razorback sucker, and mottled sculpin. Based upon two specimens from skeletal
remains in Native American middens, bonytail chub may also have inhabited the river. Of these
species, Colorado pikeminnow, razorback sucker, and bonytail chub are listed as endangered under
the Endangered Species Act of 1973. In addition, New Mexico lists the roundtail chub as
endangered; Colorado classifies the flannelmouth sucker, bluehead sucker, and roundtail chub as
species of special concern; and Utah lists the roundtail chub and Colorado River cutthroat trout as
sensitive species.

Although Colorado pikeminnow was presumed in the San Juan Basin prior to 1900, the first
confirmed records of occurrence were not until 1936 when three juveniles were captured at Alcove
Canyon, Utah. Thereafter, specimens were taken from several locations in Utah, Colorado, and
New Mexico. During a three-year study initiated in 1987, 10 adult and 18 young-of-year specimens
of Colorado pikeminnow were captured. This effort documented the persistence of the species from
about Shiprock, New Mexico, downstream to Lake Powell and successful reproduction in New
Mexico and Utah. Subsequently, nine additional specimens of Colorado pikeminnow were captured
between Shiprock and Four Comers in 1991 and one was observed about 5 miles upstream of
Shiprock.

Razorback sucker were reported ascending the Animas River in the 1890's, but specimen
confirmation of its presence in the San Juan Basin was not made until 1976 when two adults were
found in a floodplain pond near Bluff, Utah. During the 1987-1990 study, razorback sucker adults
were collected in the San Juan arm of Lake Powell and a single male was found near Bluff, Utah.

Occurrence of bonytail in the San Juan Basin is uncertain as the record consists only of skeletal
remains from Native American middens and two questionable specimens collected prior to 1930.
One specimen is a hybrid of roundtail chub and another chub species (possibly bonytail or
humpback chub), and the second has not been critically examined.

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S ecies
Colorado River Cutthroat Trout
Roundtail Chub
Bon ail
Colorado Pikeminnow
S eckled Dace
Flannelmouth Sucker
Bluehead Sucker
Razorback Sucker
Mottled Scul in

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