Strategies to Maximize the Efficiency of Using Parentage-based Tagging as a Tool to Meet

Management and Research Objectives

By Carl StiefelIdaho Department of Fish and Game

Idaho’s Hatchery Steelhead Programs

• 5 Hatcheries• Annually Release

– 7.6 m hatchery smolts– Of which, 1.9 m (25%)

are coded-wired tagged (CWT)

Salmon River

Clearwater River

SnakeRiver

• Anderson and Garza (2005)• Annual sampling and genotyping of broodstock• Parental genotype database• Assign the progeny to parents• Essentially all fish are genetically tagged• Pilot Study (Steele et al. IDFG Report 11-111)

– 100 % assignment accuracy– 97.3% assignment rate

Parentage-based tagging (PBT)

or

• Advantages of PBT• Noninvasive tag• No tag loss• No tag induced effects• Near complete representation of production• Nonlethal sampling• Extremely high resolution, identify parents!!!

• Brood Year• Hatchery• Rearing information

Why use PBT?

Can PBT be applied at a mass production scale and still meet management and research needs?

Depends on • Ability to track family units through culture phase of

life cycle.• Level of interest.

– Large scale• To brood year, hatchery, and stock.

– Adult accounting

– Moderate scale• To release group.

– Fishery management– Straying

– Fine scale• To experimental group.

– Heritability of Age at Maturity– Manipulative Rearing Experiments

Facility/program characteristics that facilitate tracking of family units to release group

• Every hatchery will require a unique PBT Plan/Model.

• Lumping family units is good.• Splitting family units may cause

complications if not managed.• Release goals set in intervals of the

largest group of intact family units.

Best case scenariolumping to the release

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Largest group of intact family units

Best case scenariolumping to the release

Worst case scenariolumping and splitting

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Maximized PBT Scenario

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Release group size are in intervals of your largest group of intact family units.

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M&E activities do not have to dictate release goals!!!!

Egg

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sAlternative scenario

lumping and managed splitting

Alternative scenario lumping and managed splitting

Vat-A

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Vat-C

ReleaseGroup A

ReleaseGroup B

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M&E activities do not have to dictate release goals!!!!

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Vat-A

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M&E activities do not have to dictate release goals!!!!

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75% PBTTagging Rate

60% PBTTagging Rate

Alternative scenario lumping and managed splitting

Approaches to tracking family units to release group

– Set release group size in intervals of the largest group of intact family units.

– When not possible due to logistics or management needs.

• Limit the number of split family units.– Apply a “PBT tagging rate”.

• Pool multiple release groups into a single release group.

Considerations for hatcheries regarding PBT

• More detail oriented than “standard production”– Minimize or eliminate “topping off” to meet production goals– Develop egg request for each release group

• Maintaining intact family units during– Egg enumeration– Marking

• Catastrophic events may impact ability to track family units– This has happened and has been managed effectively

• Coordination of information essential– Tracking family groups– Relating release information to recovered samples

Sounds like a logistic nightmare?

• Not really– Initial PBT plan development

• Requires a lot of work and coordination• Unique for each facility

– Subsequent PBT plan refinement/modification• Is much easier

Proposed PBT Tagging Rate Brood Year 2012

• Of the 7.6 m steelhead to be released.• Approximately 6.8 m (90%) will be PBT tagged

to release group.– The remaining 10% will be PBT tagged to hatchery.

• 24 out of 28 release groups have a PBT tagging rate of at least 80%.

By tracking family units to release group you can…

• Assess contribution to run.• Evaluate contribution to fisheries.• Evaluate hatchery straying into natural

production areas.• Conduct other research

– Manipulative Rearing Experiments

Conclusions• M&E and hatchery staff need to work closely together to develop a PBT

plan for each facility.• Facility/program characteristics that facilitate tracking family units to

release group.– Lumping production to release.– Large release group sizes.– Release group size in intervals of your largest group of intact family units.

• Even with less than ideal circumstances a large proportion of family units can be tracked to release group resulting in a high “PBT tagging rate”.

• These same strategies could be employed at a finer scale, such as experimental unit, as well.

• Get creative, you would be surprised at what can be accomplished in maximizing the opportunities to utilize PBT.

Acknowledgments

• IDFG Genetics Lab– Matt Campbell– Craig Steele

• Hatchery Staff– Clearwater, Dworshak National,

Hagerman National, Magic Valley, Niagara Springs fish hatcheries.

• PSMFC Marking Crew• Stuart Rosenberger –IPC• Brian Leth

Questions?