Fig. 6. (A) Gill Na⁺,K⁺-ATPase activity (µmol ADP mg^-1 protein h^-1) for fish arriving on the spawning grounds in the Harrison (H), Shuswap (Sh), Chilko (C), Quesnel (Q) Watersheds in 2002 and 2003. ^*Significant difference between years for the same stock. Samples with a common letter do not differ significantly. Sample size ranged from 15 to 30, except for Harrison, 2003 where sample size was 3. (B) The absolute change in gill Gill Na⁺,K⁺-ATPase activity between fish captured at Whonnock and fish arriving on the spawning grounds for the different stocks examined plotted as a function of migration time within freshwater. Migration rates are based on estimates from English et al. (2004) and differences in dates between sampling at the two locations.