Hooking mortality

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Hooking mortality behavior of a Puget Sound
population

• Charmane Ashbrook, Michael Mizell, Ken Warheit

Tomelleri
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• ESA listing
• Sport selective fishery impacts?

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More reasons

• Variable survival estimates
• Use a control to extricate effects of handling
  and tagging

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Plan

• Part A, estimate survival
• Part 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

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Plan

• Part A, estimate immediate and post-release
  survival
• Part 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

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Plan

• Part A, estimate immediate and post-release
  survival
• Part 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

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Methods

• Capture 30 wild winter steelhead on hook and line
• Capture 30 control fish
• Radio tag small population, follow movement
• Insert tags surgically, potential iteroparity
• Track fish using fixed and mobile (vehicle)
  receivers
• Two year study
• Tag fish regardless of wounds, bleeding
• Collect photo, length, scale, DNA, and weight
  data
• Use GIS to track fish

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Methods II

• Three parts to survival
• Immediate from capture until release
• Post-release from release until presumed
  spawning
• Out-migration from presumed spawning until
  out-migrate from river (kelt)

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Pre-season 2009 Little water problem
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Results I
Control fish (trap) 2008 12 2009 7 Control X
fish (previously hooked) 2008 7 2009 1
Treatment fish (sport) 2008 27 2009 27
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Estimating survival

• Conceptual example
• Immediate post-release total survival

by Keeley, E.R. 
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Results II --survival
Group Immediate survival Post-release to presumed spawning Survival
Control 100 100
Control X 100 100
Treatment 100 100
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Estimating survival--take two

• Conceptual example using out-migration as proxy
  for spawning
• Immediate post-release out-migration total
  survival

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Results III --survival
Group 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.
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Results IV--age structure
Age 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.
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Results V --Gender
Year Group Lived Died 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 p0.08 2009 Chi square test
p0.56
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Results VI--DNA analysis

• 2009 group had 5 fish with hatchery parentage
• 3 controls and 2 treatment
• 3 kelted
• 2 with 2.1 age structure 2 spawn check
• Feb 23rd to Mar 28th
• 2008 group had 8 fish with hatchery parentage
• 7 controls and 1 treatment
• 7 kelted
• 3 with 3 age structure 1 spawn check
• Feb 7th to Mar 6th

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Comparison with other research

• Evolution of hooking mortality studies,
  technology statistical improvements
• Recent studies
• California, summers, n126 hook location
  temperature gt21C. 1995 1996. Fish observed for
  36 hours.
• British Columbia, winters, n226 radio tag. Tag
  regurgitation, no control, bleeding fish not
  included?

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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 gt first time spawners based on scale
  analysis

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Further explorations

• Evaluate in higher gradient, further in-river
  system fish that must travel further may have a
  lower survival
• In estuary environment survival will likely be
  lower
• Estimate recapture survival
• Kelt migration and movement patterns in saltwater
• Consider 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

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Acknowledgements

• Samish Hatchery Crew
• Bob Leland Steve Schroder
• Equipment USGS, University of Idaho, Pete Hahn
• Technicians 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

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Hook location
Treatment (sport caught) 34 maxillary 1 behind
eye 3 snout 1 top of head 1 no data Control X
(hatchery weir, previously hooked) 6 maxillary 1
no data
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Fishing gear
Artificial bait Corky Eggs Float Sand
shrimp Yarn
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Gender
2008 2008 2008 2008
Group Control Treatment Hooked Control
Female 8 15 4
Male 4 12 3
Unknown 0 0 0
Both 12 27 7
2009 2009 2009 2009
Group Control Treatment Hooked Control
Female 4 13 0
Male 3 13 1
Unknown 0 1 0
Both 7 27 1