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3. Autumn (September 23 - December 21). Colorado squawfish Flows of the Yampa River that favor nursery habitats in the downstream Green River should be maintained until at least November 1 of each year, for growth and survival of young. Higher Yampa River flows (about 50% exceedence or more) are desirable for adults and juveniles until ice cover, and these would reduce frequency of ice breakup, ice jams and shoreline scouring. It is preferable not to increase flows and disrupt this cover until the following spring (see winter recommendations). Razorback sucker High, fluctuating flows in late autumn resulted in increased fish activity and presumably stressed on the fish. This may be most critical with ice conditions. Moderate to average, stable flows are recommended (50-75% exceedence values). Humpback chub Low flows (in 1989) resulted in poor habitat conditions for humpback chub in Yampa Canyon. Field inspections indicated that the river consisted of semi- isolated runs and pools which effectively limited fish movement and reduced occupied habitat to a low level. Flows lower than about the 75% exceedence value are not recommended. Autumn recommendations Stable flow conditions at the 50% exceedence value are recommended to provide nursery habitat for the Colorado squawfish and humpback chub until ice formation. High flows that would cause ice breakup and jamming should be avoided. 4. Winter (December 22 - March 20) Colorado squawfish Stable winter flows reduce the scouring of shoreline habitats by ice. Flows at the 50% exceedence value (about 400 cfs) were acceptable for adult habitat during the 1986-88 winter study, when Colorado squawfish were actively foraging in shallow shoreline habitats. Razorback sucker Fluctuating winter flows with icy conditions may stress the overwintering fish. 6