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1 since sampling began in 1993; no sampling has been conducted there since 1999. Documenting consistent annual reproduction might be considered something of a surprise given the apparent rarity of wild adult razorback suckers. This is particularly true in the lower Green River, given the number of razorback sucker larvae captured is relatively high and no large spawning aggregations have ever been detected with certainty in that area (Muth et al. 1998, Chart et al. 1999}. We feel reasonably certain that larvae captured in the lower Green River were produced there rather than in the middle Green River based on the presence of larvae in that area prior to their appearance in the middle Green River. The probability of documenting reproduction in the middle Green River is perhaps more certain given that a known spawning aggregation exists, but the number of wild spawning adults was certainly low and appeared to be declining. Most razorback suckers stocked in the middle Green River from 1996 to 1999 are, or soon will be, of reproductive size and age, and captures of those fish in ripe condition on or near the spawning bar suggested that those fish may be already contributing to annual reproduction. Annual sampling with light traps appeared to be an effective sampling technique to document reproduction by rare razorback suckers in the Green River. We do not know if the number of larvae captured in light traps was a reliable indicator of their abundance. As discussed by Muth et al. (1998), annual or even inter-annual differences in environmental conditions may bias abundance indices such as CPUE that are estimated from light-trap sampling. For example, a high flow year that creates an abundance of flood plain habitat would widely disperse even a large number of larvae, whereas a lower flow year would concentrate even a few larvae into a small amount of sampling habitat. Thus, inferences about abundance data from light-trap sampling 25