Assessment of the Kokanee Salmon Stocking Program in Lake Roosevelt, WA

This study determined which kokanee stock performed best in Lake Roosevelt, WA: Lake Whatcom (LW), Meadow Creek (MC), or Lake Roosevelt (LR). The Lake Roosevelt stock was created by collecting eggs from MC, LW, and non-marked kokanee that returned to Hawk Creek and raising them to the residualized smolt stage at the Spokane Tribal Hatchery for release back into Lake Roosevelt. Historically, Lake Roosevelt has been plagued with low return runs (< .05 %) and unequal sex rations (30:1). Fall spawning run data (2009 – 2011) was analyzed to assess the percentage of each stock returning to an adult weir installed at Hawk Creek. Boat electrofishing surveys were also conducted at 30 tributary mouths historically utilized by kokanee. In 2009, 507,970 LW and 2,790 LR fish were released; 8,667 LW (1.7%) and 209 LR (7.5%) were recovered. In 2010, 118,835 MC and 12,420 LR fish were released; 7,653 MC (6.4%) and 964 LR (7.8%) were recovered. In 2011, 220,221 LW and 11,102 LR fish were released; 141 LW (0.06%) and 206 LR (1.9%) were recovered. Chi-Square test of independence indicated that significantly more LR fish than LW or MC fish were recovered per year: 2009 (χ²=9,298, p<0.0001), 2010 (χ ²=80.5, p<0.0001) and 2011 (χ ²=1,928, p<0.0001). Female/male sex ratios were 33:1 LW and 1.6:1 LR (2009); 5:1 MC and 1.4:1 LR (2010); and 6:1 LW and 1.6:1 LR (2011). Chi-Square goodness-of-fit test indicated that LR fish returned in more equal sex ratios than LW or MC fish: 2009 (χ² =7,683, p<0.0001), 2010 (χ²=3,497, p<0.0001) and 2011 (χ ²=83.5, p<0.0001).