1. Using PIT tags to evaluate the post- release survival of spring chinook salmon following their release from commercial nets C. E. Ashbrook, J. R. Skalski, K.W.Yi, R. Townsend, J.F. Dixon, and E. Schwartz Image provided with permission by Windsor Nature Discovery, LLC www..nature-discovery.com

2. Why selective fisheries? Harvest commingled populations at different rates. 1.Increase harvest rates on hatchery production. 2.Minimize impact to depressed and endangered stocks.

3. Visual mark—adipose fin clip

4. Short soaks and careful handling techniques are not enough to improve long-term survival of gill net captured chinook. Combined with the tangle net, they do improve long-term survival.

5. Chinook salmon with gill and wedge marks

6. Chinook salmon with tangle marks

7. Objectives Compare 4.5” and 4.25” tangle nets. Evaluate: 1, Immediate survival, catch efficiency, and bycatch. 2. Long-term (post-release) survival with jaw and PIT tags. 3. Controls released at two locations. 4. Passage timing.

8. Upriver Toward Pacific Ocean Fish Trap Beacon Rock

10. Evaluate condition and length

12. Immediate survival Study year Mesh size (inches) Immediate survival % N 2003Tangle98.01172 No significant difference between immediate mortality for spring chinook salmon captured in 4.5” and 4.25” nets.

13. Catch efficiency for paired nets 2003: No significant difference between 4.5” and 4.25” tangle nets.

14. Bycatch Primarily sturgeon and suckers Reduced by avoiding fishing in concentration areas.

16. Preliminary 2003 survival estimates Group Jaw tag recovery rate PIT tag detection rate Jaw tag survival estimate PIT tag survival estimate Control at Bonne. dam 19.0%97.6%65.4% (52.6-78.3) 79.8% (77.2-82.4) Control below Bonne. dam 16.5%95.6%75.2% (60.0-90.4) 81.5% (84.2-78.7) Tangle net12.7%79.5%

17. Long-term survival measured by releasing fish to swim freely is very different than immediate survival or net pen holding survival. PIT tag post-release survival estimates are similar to jaw tag post-release survival estimates. Conclusions

18. Next steps: Evaluate passage timing. Evaluate survival excluding Bonneville detections. Recommendations: Additional year with two controls. Additional year with PIT tags. Evaluate spawning success.