9533

• UCREFRP Catalog Number: 9533
• Author: Muth, R. T. and E. Wick.
• Title: Field Studies on Larval Razorback Sucker in Canyonlands National Park and Glen Canyon National Recreation Area, 1993-1995.
• USFW Year: 1997.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

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patterns of growth and survival; data could be used in developing recruitment models for
razorback sucker early life stages.

Beginning in 1997, a study funded by the USGS (in cooperation with the NPS, Utah
Division of Wildlife Resources, and LFL) will be conducted to quantify the temporal
abundance of zooplankton, phytoplankton, and benthic invertebrates in selected nursery
habitats on the lower Green River during spring-early summer; selected water-quality
parameters will also be measured.

. The importance of the Colorado River inflow to Lake Powell in providing nursery
habitat for larval razorback sucker during certain years is unknown. The capture of 15
larvae in Sheep Canyon in 1993 suggests that flowing, lotic conditions throughout the
inflow are necessary for larval transport into nursery habitats. Sampling for razorback
sucker larvae in the Colorado River inflow should be resumed to address this
question.

. Effective methods for capturing razorback sucker juveniles need to be
developed. A NPS/NRPP proposal has been submitted to begin addressing this need
in the Colorado River inflow to Lake Powell in 1998, and sampling for early juveniles
using light traps with 6-mm wide fish-entry slots was attempted by the Utah Division of
Wildlife Resources as part of the razorback sucker monitoring program in 1996 but
without success.

REFERENCES

Brothers, E. B. 1990. Otolith marking. American Fisheries Society Symposium 7: 183-202.

Buckley, R. M., and H. l. Blankenship. 1990. Internal extrinsic identification systems: overview
of implanted wire tags, otolith marks, and parasites. 7: 173-182.

Dabrowski, K., and K. Tsukamoto. 1986. Tetracycline tagging in coregonid embryos and
larvae. Journal of Fish Biology 29:691-698.

FLO Engineering, Inc. 1996. Green River flooded bottom lands investigation Ouary Wildlife
Refuge and Canyonlands National Park, Utah. Final report to the Recovery
Implementation Program for the Endangered Fish Species in the Upper Colorado River
Basin, Denver, Colorado.

Hawkins, J. A., and T. P. Nesler. 1991. Nonnative fishes of the upper Colorado River basin: an
issue paper. Final report of Colorado State University Larval Fish Laboratory to the
Recovery Implementation Program for the Endangered Fish Species in the Upper
Colorado River Basin, Denver, Colorado.

Lanigan, S. H., and H. M. Tyus. 1989. Population size and status of the razorback sucker in
the Green River basin, Utah and Colorado. North American Journal of Fisheries
Management 9:68-73.

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