7614

• UCREFRP Catalog Number: 7614
• Author: Valdez, R. A.
• Title: Cataract Canyon Trip Report No. 2 -- Assess Reproductive Activity of Humpback Chub -- ‎(April 11-16, 1988)‎.
• USFW Year: 1988.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

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INl'RODUCTlOO

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Background

This report is the second of nine scheduled trip reports for the 1988
Fisheries Biology and Rafting Project (Contract No. 6-CS-40- 03980) . As
specified in Section C.9.1 and F.3 of the contract, each report will be
submitted to the Bureau of Reclamation Office in Salt Lake City, UT, no later
than 15 calendar days from the completion of each trip.

A draft Final Report summarizing the three field seasons (1986, 1987,
1988) will be submitted to BOR by January 1, 1989. This draft Final Report
will summarize all data collected with appropriate statistical analyses and
comparisons including, but not limited to: all fish collections separated by
gear type and effort expended; catch-per-effort statistics; calculations of
length/age regressions for larval Colorado squawfi sh; comparisons and
correlations for collections between years. A Results and Discussion Section
will be included in this draft Final Report with conclusions and
recommendations regarding the data collected. This section of the report will
focus on the four objectives of the study. The draft Final Report will also
have a complete slide series of photographs taken of the fish and fish habitats
during the course of the investigation. BOR will review the draft Final Report
within 30 (January 31, 1989), and BIO/WEST will submit 50 copies of the Final
Report to BOR by March 31, 1989.

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Most information in the nine trip reports is presented in table format to
provide a quick synopsis of pertinent trip details and results. This includes,
as a minimum: dates of departure, number of personnel on the trip, copies of
the original data sheets, and a summary of endangered fish collected. The
purpose of trip 1 is to assess overwinter survival of YOY Colorado squawfish in
the lower Green and Colorado Rivers; trip 2 is designed to sample for humpback
and bony tail chub in possible spawning condition; trips 3-5 are intended to
locate spawning sites of endangered fish and assess spawning success; trips 6
and 8 are to locate populations of endangered fishes and assess reproductive
success; and trip 7 is to locate concentrations of humpback chub above the
confluence.

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Trip 2 was designed to sample for humpback chub and bony tail chub in
spawning condition. The presence of ripe females with strippable eggs during
spawning season would classify Cataract Canyon as a "confirmed spawning area"
(Rare and Endangered Colorado River Fishes Sensitive Areas, UCRBCC, 1984).
Cataract Canyon is currently a "suspected spawning area" with the capture of
five or more adults in one year.

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This trip was conducted in the latter part of April, when water
temperature is highest preceeding runoff. These criteria were used to allow
for use of sample gear at low prerunoff flows, and to maximize the possibility
of capturing fish in spawning condition. Valdez and Clemmer (1982) reported
that humpbacks probably spawnE~d in Black Rocks about June 2-15 of 1980, at
water temperatures of 11.5-16.0 C and flows of 21,500-26,000 cfs. In 1981, the
fish probably spawned May 15-27, at 16.0-16.5 C and .3,000-5,000 cfs. Archer et
al. (1985) found that humpback chub spawned in late June of 1983 at water

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