7152

• UCREFRP Catalog Number: 7152
• Author: Holden, P. B.
• Title: Relationship between Flows in the Yampa River and Success of Rare Fish Populations in the Green River System.
• USFW Year: 1980.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

16

Vanicek (1967) studied the Green River in Dinosaur National
Monument in 1964-1966. The major objective of his study was to deter-

mine the downstream effects of Flaming Gorge Dam, which was closed in
November 1962, on the fishes in the Green River. He sampled stations
which included Echo Park, the confluence of the Green and Yampa
rivers; Island Park, about 10 river miles below Echo Park; and Split
Mountain, about 10 miles below Island Park. He also sampled several

stations in the Green River between the mouth of the Yarnpa River and

Flaming Gorge Dam. His seining effort was high and included several days
of sampling at each station during 3 or 4 months each year.
Table 2 shows the young squawfish collected by Vanicek (1967).

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This data indicates that Colorado squawfish spawned in Dinosaur
National Monument all years between 1962-1966, but that success was

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It should be noted that in 1965, 4 members of the Aqe class III, 1962

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lower in 1965, and perhaps 1962, than the other years. The 1962 year

class was not sampled until age II, when low numbers are usually found.

cohort, were found, whereas in 1966, 5 members of the Age III, 1963
cohort, were collected. Since the 1963 year class was supposedly
IIstrong" due to large numbers of Age I and II fish caught in 1964 and
1965, respectively, the capture of similar numbers of Age III fish in-
dicates that 1962 may also have been a good year for squawfish repro-

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II,

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II,

ductive success.

Figure 8 is the length/frequencies of young squawfish presented
by Vanicek (1967). Collections in 1964 in June show large numbers of
Age I fish which ranged from 30 mm to 80 rom. In 1965, Age I fish were
30-50 mm and Age II fish were indicated to be 55-110 mm in June.

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