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Spring Sexual Condition As in previous years, there was a low percentage of ripe female HBC compared to ripe male HBC during the spring sampling of 2004 (i.e., 6 ripe females/113 ripe males in spring 2004; spring 2003 = 4/115; spring 2002 = 14/123, spring 2001 = 6/84). Gorman and Stone (1999) found similar results during the spawning seasons of 1993 to 1995 (i.e., 16/93). Hoop net catch data over the years in the LCR has consistently shown that one or two ripe females are typically accompanied by numerous ripe males (GCMRC, unpublished data). Thus, this trend does seem to hold true for the population. Gorman and Stone (1999) also found that ripe females appeared to move into aggregations of ripe males to spawn, and found that while males have a protracted time span for being in a ripe condition; females are ripe for a shorter time span. The Recovery Goals make the assumption that there is a 1: 1 effective sex ratio in terms of contributors to the next generation (USFWS 2002). Even though a 1:1 sex ratio may exist in the wild for HBC (Valdez and RyeI1995), this may not necessarily equate into a 1:1 effective sex ratio during spawning activities. As SoLile (1980) stated, "breeding structure is absolutely critical." The data suggest that the breeding structure for HBC may be more complex than simply assuming a 1:1 effective sex ratio. This is important, since the effective sex ratio has an impact on the estimation of Ne, and indeed is part of the basic equation in estimating Ne (e.g., Lande and Barrowclough 1987). Fall Abundance Estimate Like the spring abundance estimates provided for this year, the fall abundance estimates had few complications (i.e., simple rather than complex stratification methods were adequate). There was no significant difference in the length frequency distributions between the marked [M] and captured [C] fish, but was significant difference between the marked [M] and recaptured [R] fish. There was also no significant difference in the mark rates within the length strata, nor within the geographic reaches. However, because there was significant difference between the length frequencies of marked [M] and recaptured [R] fish, the estimate was stratified by length. This year's fall estimate of 2,565 (SE = 519) HBC ~ 150 mm was higher (although not significantly) than the fall 2003 estimate of 1,862 (SE = 206), and all three estimates since 2002 have been significantly higher than the abundance estimate obtained during the fall of 2001 " (N= 1,064, SE = 65). Similar to the discussion above concerning the variation in spring abundance of HBC ~ 150 mm since 2001, variations in abundance during the fall also appear to reflect annual cohort strength. For example, the strong 2001 age-O cohort is well into the 150-200 mm size category by fall of 2002 (Figure 24), and might reflect the significantly higher abundance of fish ~ 150 mm compared to fall 2001 (Figure 22). It appears that the poor age-O cohort from 2002 may be reflected in the comparatively lower fall 2003 abundance of HBC ~150 mm (Figures 22). Figure 24 partially hints at this as low spot in the numbers of HBC captured in the roughly 110-170 mm size category during fall 2003. Finally, the 2003 age-O cohort can be seen entering the 150+ mm size 27