Wahleach Project Water Use Plan Wahleach Reservoir ... - BC Hydro

shifted from age 2 fish before fertilization to predominance by age 2, 3 and 4 during
fertilization (Fig. 22). This suggests that fertilization has lead to increased survival to
older ages. The mean size of the rainbow trout range from 178.6 to 253.7 mm and
71.5-186.1 g for ages 2-4. Age 3+ fish were the most common age class caught
and they were 219.9 ± 8.7 mm and 125.1 ± 14.9 g. These fish are slightly smaller
than sizes reported by Perrin et al (2006). The cutthroat trout ranged in size from
250-540 mm (mean 315 ±18.7 g) and 143-1630 g (mean 365.8 ± 84.6 g). Ages are
not available for the cutthroat trout. The kokanee captured range from 1+ to 4+ in
age, with the majority of the fish in 2006 aged 4+ (67%). The age 4+ fish ranged in
size from 185-272 mm (mean 233 mm) in fork length and 76-254 g (mean 174 g).
These fish were in good shape with a condition factor averaging ranging from 1.19-
1.37 (mean 1.28). 3 mature males, 3 immature males, 2 mature females and 4
immature females were found in the catch, but the small sample size may not
represent the kokanee population.
RBT Frequency by year
1.0
0.8
0.6
0.4
0.2
0.0
» Fertilization Period
yr1993 1994 1995 1996 1997 1998 1999 2000 2006
1+ 2+ 3+ 4+ 5+ 6+
Figure 22. Age frequency distribution of rainbow trout caught in gill nets in years
before fertilization (1993 and 1994) and in years after fertilization (2004-2006) in
Wahleach Reservoir.
Wahleach Reservoir Fertilization Project, 2004-2006.
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