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I I I I I I I I I I I I I I I I I I I the Yampa River in May and June to the point that Little Snake River minimum temperatures often exceeded maximum temperatures on the Yampa River. In later months during baseflow, average daily temperatures were similar between both rivers but the Little Snake River had diel fluctuations as high as 200C between its daily high and low temperatures. Our most significant finding was the scarcity of nonnative fishes. Of 4,490 fish collected, 69% were native species. Five native and seven nonnative species were collected. Native species included roundtail chub, speckled dace, bluehead sucker, flannel mouth sucker, and mottled sculpin. Nonnative species included red shiner, common carp, fathead minnow, redside shiner, sand shiner, white sucker, and channel catfish. No endangered fishes were seen or collected. Species in highest abundance were native bluehead sucker (31 %), flannelmouth sucker (23%), and nonnative redside shiner (20%). Other numerically abundant species included speckled dace and sand shiner. Few common carp, white sucker, channel catfish, fathead minnow, or red shiner were collected. Larvae were collected for all species except common carp and channel catfish. Few roundtail chub larvae were collected even though juveniles and adults were fairly common. All five native species spawned within the Little Snake River. Spawning was also confirmed for five of the seven nonnative species. Channel catfish and common carp larvae were not collected and their spawning was not confirmed. The small number of nonnative fish larvae collected implied limited spawning by most nonnative fishes in the Little Snake River. After July, discharge in the Little Snake River decreased so low that many reaches were essentially devoid of fish due to insufficient water levels. During this low-flow period, fish of all sizes tended to congregate in refugia pools located in the Upper and Lower reaches. During July base-flows, the removal sampling method was effective for sampling refugia pools. The technique provided a good v