Using PIT tags to evaluate the post- release survival of spring chinook salmon following their...
-
Upload
cecil-barton -
Category
Documents
-
view
217 -
download
0
Transcript of Using PIT tags to evaluate the post- release survival of spring chinook salmon following their...
![Page 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/1.jpg)
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
![Page 2: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/2.jpg)
Why selective fisheries?
Harvest commingled populations at different rates.
1. Increase harvest rates on hatchery production.
2. Minimize impact to depressed and endangered stocks.
![Page 3: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/3.jpg)
Visual mark—adipose fin clip
![Page 4: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/4.jpg)
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.
![Page 5: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/5.jpg)
Chinook salmon with gill and wedge marks
![Page 6: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/6.jpg)
Chinook salmon with tangle marks
![Page 7: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/7.jpg)
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.
![Page 8: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/8.jpg)
Upriver
Toward Pacific Ocean
Fish Trap
Beacon Rock
![Page 9: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/9.jpg)
![Page 10: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/10.jpg)
Evaluate condition and length
![Page 11: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/11.jpg)
![Page 12: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/12.jpg)
Immediate survival
Study year
Mesh size (inches)
Immediate survival
%N
2003 Tangle 98.0 1172
No significant difference between immediate mortality for spring chinook salmon captured in 4.5” and 4.25” nets.
![Page 13: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/13.jpg)
Catch efficiency for paired nets
2003: No significant difference between 4.5” and 4.25” tangle nets.
![Page 14: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/14.jpg)
Bycatch
Primarily sturgeon and suckers
Reduced by avoiding fishing in concentration areas.
![Page 15: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/15.jpg)
![Page 16: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/16.jpg)
Preliminary 2003 survival estimates
GroupJaw tag recovery rate
PIT tag detection rate
Jaw tag survival estimat
e
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 net 12.7% 79.5%
![Page 17: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/17.jpg)
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
![Page 18: 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,](https://reader030.fdocuments.in/reader030/viewer/2022033105/56649f255503460f94c3c121/html5/thumbnails/18.jpg)
Next steps:Evaluate passage timing.Evaluate survival excluding Bonneville detections.
Recommendations:Additional year with two controls. Additional year with PIT tags.Evaluate spawning success.