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Drift net samples collected in the Green River just upstream of the Yampa River in 2002 to 2004 were used to describe species composition and abundance patterns of fish larvae transported downstream and to determine if upstream spawning of Colorado pikeminnow had occurred. Samples were collected daily in the morning (ca. 0700 to 0900 h) with conical drift nets (0.15 mZ mouth diameter, 4 m long, 560 µm mesh) set near shore in water 30 to 50-cm deep. Three nets were set on each sampling occasion for up to 2 h, but sampling ceased if debris load exceeded 3.8 L/sample. Water depth at which a white object disappeared from sight was recorded as a measure of water turbidity. General Oceanics flow meters (model 2030) suspended in each net mouth recorded water velocity. Samples were fixed immediately in 100% ethanol and fish were removed from debris within 4 h and preserved in 100% ethanol. Ethanol was used to ensure that fish otoliths or other tissues were useful for later analysis, if desired. Collection of large-bodied fish.-Most collections of large-bodied fishes were by electrofishing and (mostly in Whirlpool Canyon) trammel nets; angling was used on a limited basis. Two electrofishing sampling trips were made each year from 2002 to 2004, one in mid to late July and one in mid to late September. Inflatable raft-based Smith-Root electrofishers were employed. Water conductivity was 300 to 700 microsiemens and electrofishing units usually produced 3-6 amperes with about 350 volts. Generally, 1.5 to 3 km reaches were electrofished before fish were identified, and lengths and weights taken on about every other sample. Electrofishing effort was continuous throughout the reach and concentrated along river banks, in deep pools, riffles, eddies, or near cover. We attempted to capture all fishes that were stunned. Electrofishing samples collected in 2002 in summer (both rafts) and autumn (one raft) were potentially biased downward compared to samples collected in 2003 and 2004 because the anode and cathode plugs were switched. This caused the relatively small surface area dropper sphere in the front of the raft to become the cathode and the relatively large surface area cables positioned mid-raft to become the anodes. The result was fewer fish were attracted to the anode and sometimes came up at the side of the raft rather than the front, which resulted in less efficient sampling. However, mean capture rate of all species combined over the study period was only slightly higher when the 2002 data was excluded (2.65 fish/h average per all species, 95% CI = 9