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coefficient. An inbreeding coefficient ranges from 0 to 1, with zero being the base level (Kincaid 1983). Assuming that the base level inbreeding coefficient for the main population is zero (as there are no historical data to measure against), it is possible to determine increases in the inbreeding coefficient that could occur above Chute Falls (because of a small founder size) or below Chute Falls (because of movement of offspring from above the falls and subsequent interbreeding with the main population). The question of concern now becomes whether or not inbreeding is likely to become a problem. There should be recognition of the power of selection to eliminate detrimental variation (P. Hedrick, ASU, and Dr. C. Walters, UBC, pers. com.). If inbreeding due to finite effective population size occurs, and the population size is in the hundreds, the negative effect of fitness would probably be small for generations, and this detrimental effect may be eliminated by selection (P. Hedrick, ASU, pers. com.). For example, even if only 50 males and 50 females survived to reproduce, this would theoretically result in a rate of inbreeding increase per generation of 0.005 (Kincaid 1983). For wild stocks, Soule (1980) states that the maximum inbreeding rate should probably not exceed 0.01. Unless the translocated population fell to < 25 pairs, this number (0.01) should not theoretically be exceeded (Kincaid 1983). This does appear to assure an appropriate level, provided that the number of breeders in the translocated population remains sufficiently large from year to year (i.e., > 25 pairs, or Ne > 50). Nevertheless, a population held in check at Ne = 50 for 20 to 30 generations will lose about 25% of its genetic variation (Soule 1980). What the preceding discussion means is that severe effects of inbreeding (loss of heterozygosity) should probably not be a concern for many generations. Since humpback chub have a generation time of 8 years (USFWS 2002a), this translates into decades. However, traits such as behavior, morphology, reproductive capacity, and physiological efficiency are likely to involve quantitative genetics (Kincaid 1983). From this respect, maintaining a translocated population at 250 pairs (Ne = 500), or higher, would be desirable (Franklin 1980, Lande 1995, Lynch et al. 1995). Another factor that may negate these concerns is that the LCR is highly stochastic in nature. A small group of founders subject to high environmental stochasticity might not be expected to persist (Leigh 1981). From this perspective, the genetic concerns about inbreeding may be minimal (i.e., the founding population may have a high probability of going extinct before genetic problems have time to develop). In addition, the above risks should be tempered with the realization that overall rapid decline in the humpback chub population could potentially have significant genetic impacts and that action to slow this is important (P. Hedrick, ASU, pers. com.). A reduction in fitness because of contemporary population decline appears to be a particular problem in species with large ancestral populations (as the humpback chub), and consequent high historical variation in fitness (P. Hedrick, ASU, pers. com.). 39