6028

• UCREFRP Catalog Number: 6028
• Author: Wick, E. J., D. L. Stoneburner and J. A. Hawkins.
• Title: Observations on the Ecology of Colorado Squawfish ‎(
• USFW Year: 1983.
• Copyright Material: NO

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by the highly altered and changing flow and temperature regimes occurring
on the Green River after inlet modification in 1978. Since the decline
of squawfish numbers in the river reach between Flaming Gorge Dam and
the Yampa River was probably temperature related, one can logically
expect changing fish behavior patterns resulting from changes in
temperature regimes due to inlet modification. The reproductive
behavior of Colorado squawfish in the Upper Green has very likely been
in an altered and often changing state for the last 20 years.
CONCLUSION
The Green River Basin below Flaming Gorge Dam is now the most
productive refuge remaining for Colorado squawfish. Largely because of
the Yampa River and its amelioratory effects on the Green River, this
refuge provides the most pristine aquatic habitat available to squawfish.
The Colorado squawfish is historically the top predator in the
Colorado River system. Throughout its life cycle, this relatively
long-lived and wide-ranging fish requires a variety of habitats and, as
with most top predators, requires considerable territory. Adults live
and travel throughout the basin, sometimes migrating more than 350
kilometers. Adults migrate either upstream or downstream and between
different rivers, if necessary, to specific spawning sites, then return
to their prespawning locations. Larvae drift or migrate downstream from
the spawning grounds to nursery areas in lower portions of the basin.
As they grow, juvenile fishes expand their range, and just before
adulthood some move up tributary rivers and establish residency.
The history of extirpation in the Lower Colorado River Basin is
evidence of the vulnerability of Colorado squawfish to (1) disruptions
in migratory routes; (2) alterations in temperature, flow, and habitat;