7735

• UCREFRP Catalog Number: 7735
• Author: Bates, B., T. Chart and M. Moretti.
• Title: Colorado Squawfish Interagency Standardized Monitoring Program, Utah, 1986-90, Lower Green and Colorado Rivers.
• USFW Year: 1993.
• USFW - Doc Type: Publication Number 93-11,
• Copyright Material: NO

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this hypothesis. The relationship did not hold true in 1990 when
catch rates fell to 5.13 fish / 100m2, however the flow spike was
estimated near 70% that year. The non-native red shiner was more
abundant in 1990 backwater collections than the previous four
years, which could certainly influence squawfish abundance.
Catch rates on the lower Green were extremely low again in 1991.

Another anomaly that must be considered when discussing low
YOY abundance in 1990 (and 1991), was the increased catch rates
of juvenile squawfish that year. Juvenile squawfish may have
reached a density in the Lower Green River that they are directly
controlling the YOY cohort strength. Feeding preference studies
(stomach pumping or lavage) of the juvenile Colorado squawfish in
the lower Green would be required to substantiate such a claim.

RECOMMENDATIONS: Based on 5 years of ISHP

Juvenile/Adult Samplinq

1. continue monitoring under present protocols with the
following modifications taken into consideration:

1. Direct half of our effort each spring towards sampling
different, currently unsamp1ed areas on the lower Green
and Colorado Rivers. Maintain one ISMP stretch (half
our current effort) on lower Green and Colorado to
provide long term trend information.

2. Investigate the merits of backwater trammel netting (i.e.
"scare and snare") on both rivers.

3. Make available a current list of PIT tags implanted and the
associated capture information and summarize recapture
information annually.

4. Review the data collected by the USFWS (CRFP) from 1979-1981
at the early monitoring sites on the Green, Colorado and
White Rivers. These data are necessary to build long term
relationships.

Post Larval Sampling

1. Reduce Reach 1 on the Colorado River from RM 110 - 0 to RM
65 - 0, due to the paucity of collections upstream of RM 65.

2. Integrate habitat dimensions quantified by aerial video into
the annual reporting done by the USFWS.

3. Recommendation # 4 above applies to the Post Larval portion
of the program as well.