9383

• UCREFRP Catalog Number: 9383
• Author: SWCA, I.
• Title: Recovery Goals for the four Colorado River Endangered Fish Species.
• USFW Year: 2000.
• USFW - Doc Type: Logan.
• Copyright Material: NO

esticides and Pollutants
The potential role of pesticides and other pollutants in suppressing populations of Gila
were discussed by Wick et al. (1981). Over 16% of young roundtail chub from the Yampa and
Colorado Rivers in 1981 showed spinal deformities (Le., lordosis), possibly related to high
pesticide levels from local agricultural applications (Haynes and Muth 1981). Tyus and
Minckley (1988) c ed that spraying programs for control of pests, such as Mormon crickets
(Anabrus simplex), ose a threat to native fishes. Other pollutants in the system include
petroleum byproducts, heavy metals (e.g., mercury, lead, zine, copper), non-metalics (i.e.,
selenium), and radionucleides.
Potential spills of petroleum byproducts continue to threaten four of the six populations
of humpback chub, and could threaten the other endangered species. The Denver and Rio
Grande Western railroad tracks parallel the Colorado River at Black Rocks and upper Westwater
Canyon with risk of derailment and spill materials into the river, although no known
derailments have occurred in these ar~. susceptibility of these humpback chub populations
to toxic substances is illustrated by a large, but unquantified, fish kill in Westwater Canyon in the
1980's as the result of a large ash flow following a range wildfire high in the watershed (pers.
comm., Joe Cresto, Bureau of Land Management). The ash and large amounts of sediment
washed down Westwater Creek during a sudden thunderstorm. A similar threat from petroleum
byproducts exists for the population in the LCR with the ris cks overturning and spilling
their loads while crossing the Highway 89 bridge at Cameron zona. The Cameron bridge is
55-65 kIn upstream of the habitat occupied by humpback chu m the lower LCR. The potential
for spills of petroleum byproducts also exists for the Yampa Canyon population. Numerous
petroleum product pipelines cross or parallel the Yampa River upstream of Yampa Canyon, most
of which lack emergency shut-off valves. One pipe ruptured in the late 1980's releasing refmed
oil into the Yampa River during the spawning period for Colorado pikeminnow, possibly leading
to the complete loss of the year class (pers. comm., Steve Petersburg, National Park
State and federal hazardous wastes plans are required to be reviewed during downlist'

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Management Plan (Czapla 1999) should be used as guidelines for use of hatchery fish in

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