7166

• UCREFRP Catalog Number: 7166
• Author: Miller, W. H., et al.
• Title: Yampa River Fishes Study
• USFW Year: 1982.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

Adult Colorado squawfish recaptured in the Yampa River displayed
two types of behavior, noted by others (Funk 1957, Tyus et al. 1981).
dive "mobile" Colorado squawfish moved from 38 to 204 mi (60 km to 326
km) and three "sedentary" fish were recaptured within 2 mi (3 km) of
their release site after 12 to 18 months freedom (Table 20). The
remaining three Colorado squawfish were local recaptures, captured less
than a month and within one mile of their respective release sites.
Collections of YOY (including larvae) Colorado squawfish in the
Green River in 1979-1981 (Tyus et al. 1982) indicate a drift mechanism
for larvae. According to the theory advanced, it appears the larvae
actively drift downstream, away from the harsh environment of the
spawning site, and select quiet backwater nursery areas. Such a drift
mechanism is well known for many stream fishes. This premise tends to
explain the relatively low numbers of young Colorado squawfish collected
to the Yampa River, and illustrates the importance of passage for the
early life history stages.
Long distance (over 100 km) spawning migration in freshwater fish
species is generally uncommon in North America although Nikolsky (1961)
cites examples in Asia of pisciverous cyprinid fishes that migrate long
distances (e.g. As ius aspius, Rutilu rutilus). Other fishes of the
genus Ptychocheilus include the northern squawfish P. oregonensis and
the Sacremento squawfish (P. grandis). These two squawfishes, the only
living congeners of the Colorado squawfish, also make freshwater spaw-
nin$ migrations (Reid, 1971 and Moyle, 1976).
Other workers have postulated spawning migrations in Colorado
pquawfish and there are many reports of spring spawning migrations by
early settlers who called the Colorado squawfish "salmon" (Sigler and
Miller 1963). Joseph et al. (1977) provided a review of known inform-
ation concerning movement and spawning and concluded that large indi-
viduals possibly migrate long distances. Holden and Stalnaker (1975b)
reported increased numbers of ripe Colorado squawfish in the lower',Yampa
River in July 1968-1970. Collections made by Seethaler (1978) also
indicated increased numbers of Colorado squawfish in the lower Yampa
River in July 1974-75. Although the lower 20 mi (32 km) of the Yampa
River, was repeatedly sampled adult Colorado squawfish were found there
only between 5 June and 9 July. These findings substantiate the results
o tained by these earlier workers.
Identification and protection of long distance spawning migrations
of. Colorado squawfish may be the most significant factor for the preser-
vation of this endangered fish. The loss of fish passage may offer an
explanation for its disappearance from the lower Colorado River basin.
Plockage of such spawning migrations by the construction of dams may
result in its loss from the upper basin as well however, it is possible
that passageways might be utilized by Colorado squawfish since northern
squawfish have been reported to use them (Park and Farr 1972).
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