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For rainbow and cutthroat trout. the density and biomass estimates for October 1992 still remain significantly below the September 1989 levels for 35 of 36 comparisons (Tables 5 through 10). However, this phenomenon is probably due to other factors and probably is not a continuing reflection or delayed impact of the 100 days of 20 cfs discharge in the spring of 1990. The data contained in Table 11 support the preceding &tatement. These annual estimates of brown, rainbow. and cutthroat trout density and biomass reflect the condition of the trout population for the entire 12 mile reach of the Dolores River from Metaska Campground to the Bradfield Bridge for the spring/summer periods of 1991. 1992, and 1993. Except for Snake River cutthroat trout. almost all estimates of brown, rainbow, and total trout density and biomass increased in June 1992 and July 1993 over the levels observed in May 1991. Moreover, brown trout reproductive success in the upstream segment of the river has been continually increasing since 1988 (Table 12) with even greater numbers of young- of-the-year brown trout fingerlings collected at the three standard fall sampling sites in October 1992 than any year previously. Fish Lenqth Frequency Distributions from 1993 Samplinq Length-frequency distributions of the larger fish (~ 15 cm or 6 inches) captured during the electro fishing operations for each of the four river segments are shown in Figures 1 - 27 in the Appendix. Brown trout encountered in the three upstream river segments were quite similar in size, ranging from 10 to 54 cm total length (TL). (See Figures 1. 7, 14, and 21 for details). In the most downstream reach brown trout numbers decreased and the largest fish was 38 cm TL. The greatest numbers and largest sizes of stream-reared ("wild") rainbow trout of were found in river segment RM 1-12, ranging in size from 8 to 56 cm TL, becoming less abundant and generally smaller in size as distance from McPhee Dam increased. (See Figures 2, 8, 15, and 22 for details) . McPhee Lake rainbow trout were captured in all four river segments (Figures 4,10,16, and 23) but were most abundant in river segment RM 1-12, ranging in size from 13 to 46 cm TL. The size distribution was bi-modal indicating that representatives of at least two year classes of lake rainbow trout were encountered during sampling and most likely more than that. Like the lake rainbow trout, the size distribution of the kokanee was bi- modal as well (Figures 5, 11, 20, and 24) with most of the salmon occurring in the upstream segment (RM 1-12). Size ranged from 17 to 44 cm TL. Cutthroat trout, the least abundant of the four salmonid species encountered, were found in the two upstream river segments (Figures 3 and 9). The largest individuals, ~ 50 cm occurred in river segment RM 1-12. Large flannelmouth suckers were encountered in all four river segments (Figures 6, 12, 18, and 25) with specimens exceeding 50 cm TL occurring in every segment. Bluehead suckers (Figures 13 and 19) were relatively rare in the sample and much smaller in size-thanflannelmouthsuckers. Ripe males (extruding milt) as small as 21 cm were encountered. The roundtail chubs encountered ranged in size from 24 to 37 cm and were displaying breeding coloration, with red margins on the fins and underparts of the body. Smallmouth bass (Figure 26) ranged in size from 32 to 45 cm TL, with the majority of the sample ranging between 32 and 38 cm TL. The length frequency distribution of yellow perch (Figure 27) was tri-modal, indicating the presence of at least three year classes in the sample. Visual Implant (VI) Taqqinq and Movement Studies Beginning in April 1991, the CDOW began fish tagging operations in the -14-