1. Importance of Water Level Management to Kokanee and Bull Trout in Lake Pend Oreille

2. Lake Pend Oreille Pend Oreille River Cabinet Gorge Dam Clark Fork River Albeni Falls Dam Bayview Hope Sandpoint 10 Km IdahoIdaho MontanaMontana Idlewild Bay Scenic Bay Size = 38,300 ha, Maximum Depth = 351m

3. Natural elevations for Lake Pend Oreille

4. Natural and Managed Lake Levels Natural Managed

5. Why are kokanee important to bull trout? 60-80% of their diet is kokanee. Without kokanee, lake trout and bull trout would be in direct competition for a limited food supply.

6. Estimates of Adult Kokanee Abundance 1952 dams were built Year 1966 consistently deep lake drawdowns begin

7. Spawning habitat is the limiting factor

8. Gravel at Farragut March 2004

9. Water line Shoreline at low pool Larger rocks

10. Can we show that a varied winter water level will increase kokanee egg survival?

11. Winter Elevations in Lake Pend Oreille Experimental years

12. Methods Trawling Hydroacoustics Fry net used on trawler

13. Results

14. Lowered lake level Wild egg-to-fry survival

15. Raised lake level

16. Lowered lake level Wild egg-to-fry survival Raised lake level

17. Lowered lake level Wild egg-to-fry survival Raised lake level P< 0.05 2.4 fold increase

18. 1.Vary winter lake level 4 ft in different years. 2.Maintain a higher winter pool level for 3 years, then lower lake to replenish gravel. 3.Time full drawdown to coincide with years when kokanee numbers are low. Lake Level Management

19. 2051’ 2055’ Yes Start Is there a declared power emergency ? YesNo Rainfall prediction for Nov -Jan for Columbia River Basin Are female kokanee spawners above 70k? Was lake at 2051’ the previous year? Was lake at 2055’ each of 3 previous years? Was lake at 2051’ each of previous 2 yrs? Below normal NoYes NoYesNo Are female kokanee spawners above 70k? NoYes Was lake at 2051’ the previous year? YesNo Equal chance, normal, or above normal Was the previous year successful for chum salmon spawning (< ? % of redds dewatered)? No Yes Will this be the second year in a row the lake is lowered to 2051’? Yes No