7132

• UCREFRP Catalog Number: 7132
• Author: Jensen, B. L.
• Title: Culture Techniques for Selected Colorado River Imperiled Fishes.
• USFW Year: 1983.
• USFW - Doc Type: December 6-8, 1983.
• Copyright Material: NO

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CULTURE TECHNIQUES FOR SELECTED COLORADO RIVER
IMPERILED FISHES
Buddy L. Jensen
U.S. Fish and Wildlife Service
%A Dexter National Fish Hatchery
S P.O. Box 219
Dexter, New Mexico 88230
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INTRODUCTION
The aquatic resources of the desert west have been altered
drastically during the past 100 years. The construction of large
dams in deep canyons of southwestern rivers has had a major impact
on many native fishes. The normal fluctuating flows have been
blocked, creating large reservoirs and downstream sections dried
up or altered by hypolimnetic releases of stored water. Many of
our desert springs now have reduced flows or have dried completely
as groundwater reservoirs have receded under the constant demand
of the irrigation pump (Jensen, in press). These habitat alter-
ations (lotic to lentic, different flow and temperature regimes
and drying) have resulted in a steady decline in our native
southwestern fish fauna.
The opportunity to focus attention on work with threatened
... f 1 shery resources came with assage of the Endangered Snec' es Act
of 1973. In 1974 Dexter NFH began experimenting with holding
native fishes to determine if captive populations could be reared
in a hatchery environment. The initial efforts proved successful
and by 1978 the Dexter facility was totally engaged in holding,
spawning, rearing and distributing native desert fishes. We have
held up to 20 species of imperiled fish and are presently holding
13 species (Table 1) with more introductions planned for the
4m l_
future.
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