Hooking mortality & behavior of a Puget Sound population

Charmane Ashbrook, Michael Mizell, & Ken Warheit

Tomelleri

ESA listing

Sport selective fishery impacts?

More reasonsVariable survival estimatesUse a control to extricate effects of

handling and tagging

PlanPart A, estimate survivalPart B, estimate encounter rate

Together, these estimates enable us to estimate the impact of sport selective fisheries on wild steelhead.

Example:Yearly escapement --1000 wild fish return

50% encounter rate --500 captured with sport gear

95 % survival rate -- 475 lived following release from sport gear

5% mortality rate --25 killed by sport gear

PlanPart A, estimate immediate and post-release survivalPart B, estimate encounter rate

Together, these estimates enable us to estimate the impact of sport selective fisheries on wild steelhead.

Example:Yearly escapement --1000 wild fish return

50% encounter rate --500 captured with sport gear

95 % survival rate -- 475 lived following release from sport gear

5% mortality rate --25 killed by sport gear

PlanPart A, estimate immediate and post-release survivalPart B, estimate encounter rate

Together, these estimates enable us to estimate the impact of sport selective fisheries on wild steelhead.

Example:Yearly escapement --1000 wild fish return

50% encounter rate --500 captured with sport gear

95 % survival rate -- 475 lived following release from sport gear

5% mortality rate --25 killed by sport gear

MethodsCapture 30 wild winter steelhead on hook and lineCapture 30 control fish Radio tag –small population, follow movementInsert tags surgically, potential iteroparityTrack fish using fixed and mobile (vehicle) receiversTwo year studyTag fish regardless of wounds, bleedingCollect photo, length, scale, DNA, and weight dataUse GIS to track fish

Methods II

Three parts to survival

1. Immediate : from capture until release

2. Post-release: from release until presumed spawning

3. Out-migration: from presumed spawning until out-migrate from river (kelt)

Pre-season 2009: Little water problem

Results IControl fish (trap)2008: 122009: 7

Control X fish (previously hooked)2008: 7 2009: 1

Treatment fish (sport)2008: 27 2009: 27

Estimating survival

Conceptual example :

Immediate + post-release = total survival

by Keeley, E.R.  

Results II --survivalGroup Immediate

survivalPost-release to

presumed spawning Survival

Control 100% 100%

Control X 100% 100%

Treatment 100% 100%

Estimating survival--take two

Conceptual example using out-migration as proxy for spawning:

Immediate + post-release + out-migration = total survival

Results III --survivalGroup Kelted

after spawning

Sample size

Survival relative to control %

90% confidence

intervals

2008 Treatment 17 27 75.56 51.2-99.9

2009 Treatment 22 27 95.06 67.0-100.0

Average Treatment

---------- ---------- 85.31 -------------

2008 Control X 5 7 85.71 47.4-100.0

2009 Control X 1 0 0.00 ------

2008 Control 10 12 ----- ---------

2009 Control 6 7 ----- ---------

There is a cost to being captured with sport gear.

Results IV--age structureAge Number

for 2008

Number for 2009

Notes

2.1+ 15 21 One fish had one spawning check (2009)

2.2+ 7 4

3.1+ 4 0 One fish had one spawning check (2008)

3.2+ 4 0

R.1+

10 5

R.2+

6 0 One fish had 2 spawning checks (2008)Samish steelhead can spawn multiple times but most

spawn only once and after 1 year in saltwater.

Results V --Gender Year Group Live

dDied Total

2008 Female

22 5 27

2008 Male 11 8 19

2008 Both 33 13 46

2009 Female

13 2 15

2009 Male 15 4 19

2009 Both 28 6 34

2008 more females out-migrated (kelted) than males. Consistent with other studies and evolutionary theory.

2008 Chi square test p=0.082009 Chi square test p=0.56

Results VI--DNA analysis 2009 group had 5 fish with hatchery parentage

3 controls and 2 treatment3 kelted2 with 2.1+ age structure; 2 spawn checkFeb 23rd to Mar 28th

2008 group had 8 fish with hatchery parentage7 controls and 1 treatment7 kelted3 with 3+ age structure; 1 spawn checkFeb 7th to Mar 6th

Comparison with other researchEvolution of hooking mortality studies, technology

& statistical improvementsRecent studies

California, summers, n=126 hook location & temperature >21C. 1995 & 1996. Fish observed for 36 hours.

British Columbia, winters, n=226 radio tag. Tag regurgitation, no control, bleeding fish not included?

Conclusions

There is a biological cost to sport fishing, 15%

Relatively high kelting rate may be typical for this kind of stream, low gradient and near saltwater

Fair % of “wild” fish had hatchery influence

Despite high kelting rate, relatively few fish were > first time spawners based on scale analysis

Further explorationsEvaluate in higher gradient, further in-river system;

fish that must travel further may have a lower survival

In estuary environment survival will likely be lowerEstimate recapture survival Kelt migration and movement patterns in saltwaterConsider if management objective to separate

hatchery and wild fish based on return timing is successful

Summer steelhead survival may be lower because of warmer water and longer time in freshwater

Estimate encounter rate to estimate impact to population

Acknowledgements

Samish Hatchery CrewBob Leland & Steve Schroder Equipment: USGS, University of Idaho, &

Pete HahnTechnicians: Jen Mertes, Ryan Regner, Jim

Crook, Faith Sandretzky, and Kyle Gulbranson

Earl Steele and his fisheries class at Bellingham Technical College; Jim Naranovich

Fishermen: Brett Barkdull, Curt Kraemer, and local volunteers

Hook location

Treatment (sport caught)34 maxillary1 behind eye3 snout1 top of head1 no data

Control X (hatchery weir, previously hooked)6 maxillary1 no data

Artificial baitCorkyEggsFloatSand shrimpYarn

Fishing gear

Gender

2009

Group Control Treatment

Hooked Control

Female 4 13 0

Male 3 13 1

Unknown

0 1 0

Both 7 27 1

2008

Group Control Treatment

Hooked Control

Female 8 15 4

Male 4 12 3

Unknown

0 0 0

Both 12 27 7