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26 6.) When using drift-nets that are set in order to achieve triplicated sampling, differences in water volumes sampled may become significant for sampling times exceeding one hour. It is recommended that duration of drift-net samples in the Upper Basin be regulated by existing flow and suspended debris conditions, and that these environmental factors be given primary consideration with regard to the intended sample design and data analysis. 7.) Representative sampling of drifting larval Colorado squawfish may be best achieved by combined seineidrift-net sampling or minimizing intervals between drift-net samples to 2 days or less. 8.) Results of diel drift sampling over 1983-85 indicate no generalized pattern or preference in diel drift can be concluded for Colorado squawfish or any of the Yampa River fish species. It is obvious that sampling immediately below the primary spawning area in Yampa Canyon is best suited to document diel periodicity for Colorado squawfish larvae, and that more detailed monitoring of environmental conditions such as turbidity should be incorporated into any further research in the Upper Basin regarding diel periodicity in larval transport. 9.) Peaks in predicted spawning activity by adult Colorado squawfish appear to be correlated with 'fluctuating flow conditions occurring near the baseline of the hydrograph following spring runoff. Results from 1983-1985 indicate a resurgence in flows of 30 m~/s in a period of 1-2 days marked the beginning of significant spawning activity. 10.) Decrease in flows below 55-60 m3/s appear to mark the cessation of significant spawning activity in 1983-1985. ACKNOWLEDGEMENTS The author wishes to acknowledge the assistance of Don Weber and Robert Muth in the critical review of this report, and the efforts of Steve Platania, Hal Copeland, and Richard Bullough in the collection of field data.