7229

• UCREFRP Catalog Number: 7229
• Author: Kaeding, L. R. and M. A. Zimmerman
• Title: Life History and Ecology of the Humpback Chub in the Little Colorado and Colorado Rivers of the Grand Canyon
• USFW Year: 1983
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

BIOLOGY OF HUMPBACK CHUBS IN THE GRAND CANYON
581
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OCT NOV DEC I JAN FEB MAR APR MAY JUN JUL AUG SEP OCT
FicuaF 2.-Chronologies of Little Colorado River- and Colorado River 5-day mean water temperatures (above) and of
Colorado River surface elevations (below). Vertical bars are ranges. Data for 180-181 are from the present study;
154-1957 data predate construction of Glen Canyon Dam on the Colorado Raver upstream of Grand Canyon.
quency distributions for fish up to about 3 years
old and 250-300 mm long (Fig. 3). New annuli
were observed on few scales collected in Feb-
ruary but were present on most scales in May.
There was no evidence of the formation of false
checks. The first annulus formed when fish
reached a length of about 100 mm and an age
of 1 year. The annual increase in length of Little
Colorado River humpback chubs was largest
during the first 3 years of life, to a total length
of 250-300 mm. Age-and-growth characteris-
tics of humpback chubs in the Little Colorado
and at the confluence of the rivers (C 4) were
similar.