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Independent Scientific Advisory BoardJune 12, 2003

A Review of Salmon and Steelhead Supplementation

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Supplementation1 is an artificial production strategy to increase abundance of a natural population, while maintaining fitness of the natural population and limiting ecological impacts on non-target species

1 RASP (1992)

time

Salmon Abundance

3Conventional Strategy - Segregated Population

Natural Population

Hatchery Population

Conventional Artificial Production vs. Supplementation

Natural-origin smolts

Natural-origin adults

Common Migration and Marine Environments

Mixture of hatchery-origin andnatural-origin fish

Hatchery-origin smolts

Hatchery-origin adults

Hatchery Strays

4Supplementation Strategy - Integregated Population

Natural Population

Hatchery Population

Conventional Artificial Production vs. Supplementation

Natural-origin smolts

Natural-origin adults Common

Migration and Marine Environments

Mixture of hatchery-origin andnatural-origin fish

Hatchery-origin smolts

Hatchery-origin adults

Natural-origin adults

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Requires females spawning in a hatchery to exceed the productivity of females spawning naturally

Hatchery Productivity (Ra)

Natural Productivity (Rw)

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Requires reproduction of hatchery-origin adults in the wild

Hatchery Component

Natural Component

N = 5 N = 6 N = 7

T0 T1T2

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Uncertainties

Habitat:

Genetic/Evolutionary:

Demographic:

The question still remains, is supplementation effective?

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NOAA request: Consider the benefits and risks of supplementation to natural populations of salmon and steelhead.

Council request: Can artificial and natural production be integrated to increase the capacity and productivity of the combined population over the foreseeable future.

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The ISAB Investigated:

Ecological and Genetic Theory Applied to Supplementation

Columbia River Basin Supplementation Experiments

Supplementation Risk-benefit Assessment Tools

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Genetic Theory:Genetic risks to a natural populations

Natural PopulationGene Pool

Domestication SelectionAdaptation to hatchery spawning, rearing, and release

Inbreeding Depressionsmall founding numbersproduce large numbersof related individuals

Outbreeding Depressionhorse x donkey = sterile mulefall x spring chinook = ?

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Genetic Theory:Domestication Selection-Adaptation to a Hatchery Environment

Selection is a consequence of the differential survival (production) of adults by different families

Differential success of reproduction in Forks Hatchery steelhead

Differential reproduction can be large among hatchery-spawned families providing the opportunity for domestication selection

Differential Success of Reproduction

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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Adult Production from Breeding

Fre

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cy Females

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Ecological Theory:Any benefit to population abundance depends on:

Intrinsic biological parameters of the stock in its environment

Productivity of the hatchery (Ra) and natural (Rw) spawners

Policy constraints and management control variables

Broodstock mining rate

Proportion of natural population that consists of hatchery-origin adults

Harvest rate

Harvest selectivity

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Ecological Theory:Conclusions from Modeling

Ongoing supplementation can be expected to increase the number of naturally spawning salmon and the potential for harvest.

The increased population size and productivity attributable to supplementation will likely not persist once supplementation ceases.

Supplementation can reduce natural spawning fitness which will persist for some number of generations after the termination of supplementation.

Natural spawning fitness can decrease with increases in the broodstock mining rate, the harvest rate, and in the proportion of hatchery-origin versus natural-origin adults taken for broodstock.

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Quantifying Benefits and Risks:Performance indicators and standards

Abundance:Abundance of Natural-Origin AdultsAbundance of Hatchery-Origin Adults

Productivity:Replacement rate of Natural spawning (Rw)

Replacement rate of Hatchery spawning (Ra)

Long-term Fitness:Rw after supplementation ceases

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Quantifying Benefits and Risks:Performance indicators and standards - Adult Abundance

Natural-origin and hatchery-origin adult abundance is required to confirm thathatchery-origin adults are “adding to”, not replacing or substituting for, natural-origin adults.

Natural Adults

Hatchery Adults

Hatchery Adults

Natural Adults

Demographically Successful Supplementation

Unsuccessful Supplementation

Total Adults Total Adults

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Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams

The challenge to quantifying supplementation effects is detecting treatmenteffects against a background of high natural variability

-2.0

-1.0

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1974 1979 1984 1989 1994

Brood Year

Ln

(R)

JohnDayUmatillaJoseph

Productivity Variation in Oregon Steelhead

17Summer Chinook Aerial Redd Counts

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78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00

Year

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Okanogan River

Similkameen River

Reference sites are required to distinguish effects of supplementation from local background variation and out-of-basin effects.

Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams

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Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams

Judging Supplementation as a Success or Failure?

Supplemented

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Supplemented

Nat

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Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams

Demographically Successful Supplementation

Supplemented

Reference

Nat

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adu

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Supplemented

Reference

Unsuccessful Supplementation

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Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams

Judging Supplementation as a Success or Failure?

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Quantifying Benefits and Risks:Performance indicators and standards - Cohort Analysis

Estimating population statistics is difficult because salmon and steelhead have very complex life-histories.

Brood Year

Return Year

1 2 3

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Assessing Columbia River Basin Supplementation Experiments

Projects:1. Hood River winter-run steelhead

2. Umatilla River summer-run steelhead

3. Yakima River spring-run chinook

4. Wenatchee River spring-run chinook

5. Similkameen River summer-run chinook

6. Tucannon River spring-run chinook

7. Imnaha River spring-run chinook

8. Imnaha River summer-run steelhead

9. Idaho Supplementation Studies spring-run chinook

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Assessing Columbia River Basin Supplementation Experiments

What is known about supplementation and largely undisputed.

A. There is a juvenile survival benefit attributable to rearing in the protected hatchery environment

Egg-to-Smolt Survival Rate

HatcheryHood River winter-run steelhead 68.0%Tucannon River spring-run chinook 73.0%

NaturalHood River winter-run steelhead 1.2%Tucannon River spring-run chinook 4.2%

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Assessing Columbia River Basin Supplementation Experiments

B. Smolt-to-adult return rates (SARs) are typically higher for natural-origin adults than for hatchery-origin adults.

Smolt-to-Adult Survival Rate

HatcheryHood River winter-run steelhead 0.68%Tucannon River spring-run chinook 0.22%Yakima River spring-run chinook 5.85%

NaturalHood River winter-run steelhead 3.80%Tucannon River spring-run chinook 1.63%Yakima River spring-run chinook 6.50%

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Assessing Columbia River Basin Supplementation Experiments

C. Adult replacement rate (adult recruits per spawner) is greater for hatchery than for naturally reared juveniles

Adult Recruits Per Spawner

Hatchery (Ra) Imnaha River spring-run chinook 4.00Tucannon River spring-run chinook 2.52Hood River winter-run steelhead 8.49Umatilla River summer-run steelhead 2.86

Natural (Rw)Imnaha River spring-run chinook 0.50Tucannon River spring-run chinook 0.86Hood River winter-run steelhead 0.94Umatilla River summer-run steelhead 0.60

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SAR Adult Production

Standard

(%)

Observed1 Standard Observed1

Hood - SH 4.5 0.68 3800 320

Umatilla - SH 2.7 0.40 1500 592

Imnaha - Ch 0.65 ------ 3210 462

Imnaha - SH 0.61 0.27 2000 849

Tucannon - Ch 0.87 0.15 1152 432

Assessing Columbia River Basin Supplementation Experiments

D. SARs for hatchery produced smolts were substantially lower than programs targets. Consequently, the yield of adult salmon and steelhead did not achieve performance standards.

1. Based on different sets of years

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Assessing Columbia River Basin Supplementation Experiments

E. Hatchery-origin adults on the spawning grounds in the late 1980s and early 1990s did not prevent declines in the abundance of natural-origin adults in the mid-1990s.

0200400600800

100012001400160018002000

Natural

Hatchery

Imnaha River Summer-run Steelhead

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Assessing Columbia River Basin Supplementation Experiments

E. (continued)

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NaturalHatchery

Tucannon spring-run chinook

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Assessing Columbia River Basin Supplementation Experiments

F. Relatively large proportions of hatchery-origin adults are being used as broodfish in hatchery spawning

Range MeanHood River winter-run steelhead 0 - 47 45Umatilla River summer-run steelhead 0 - 33 8Wenatchee River spring-run chinook 0 - 79 NASimilkameen River summer-run chinook 36 -67 45Yakima River spring-run chinook 0 0Imnaha River summer-run steelhead 0 - 92 54Imnaha River spring-run chinook 0 - 97 65Tucannon River spring-run chinook 0 - 97 50

Proportion of hatchery-origin adults used as broodfish in hatchery spawning

As the proportion of hatchery-origin adults are used in hatchery spawning, projects will become increasingly more “conventional” in their management. Hatchery-origin adults from conventional production have poor natural spawning fitness.

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Stream CategoryNumber of

YearsPercent Stray

Hatchery Adults

American River Treatment 7 61Big Flat Creek Treatment 7 63Brushy Fork Creek Control 7 44Clear Creek Treatment 7 31Colt Killed Creek Treatment 6 64Crooked Fork Creek Control 7 58Crooked River Treatment 7 30Eldorado Creek Control 3 22Herd Creek Treatment 4 8Lolo Creek Treatment 7 38Newsome Creek Treatment 5 44Papoose Treatment 7 41Pete King Creek Treatment 1 0Red River Treatment 7 43Squaw Creek Treatment 3 33White Cap Creek Control ND1. From Lutch et al. (2003)

Assessing Columbia River Basin Supplementation Experiments

G. Stray adults from conventional hatcheries compromise experimental designs

Stray hatchery chinook salmon recovered in ISS study streams in the Clearwater subbasin during carcass surveys.

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Assessing Columbia River Basin Supplementation Experiments

H. Stray adults from conventional hatcheries are producing de facto supplementation with the worst possible breeding protocol.

ODFW data

Stray Hatchery Adults in the Deschutes River

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Natural Adults

Sub basin Hatchery Adults

Stray Hatchery Adults

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Assessing Columbia River Basin Supplementation Experiments

H. The full suite of performance indicators is available for only a few projects

Hood River winter-run steelhead Abundance and ProductionStandards

Adult Returns DispositionProduction

Rates

Hatchery NaturalNaturalSpawning

HatcherySpawning

Harvest Ra Rw

3800 1200 2400 90 2510 42 0.50

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ISAB Recommendations

Use supplementation sparingly.

Only use natural-origin adults from the target population as parents in hatchery spawning.

Establish and monitor performance standards.

Conduct all supplementation projects with explicit experimental designs.

Coordinate the multiple supplementation projects as a basinwide adaptive management experiment.

Ensure that individual projects are collecting the data necessary to test their effectiveness and ensure regional coordination of the multiple experiments.

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NOAA Question

NOAA: What are the benefits and risks of supplementation to natural populations?

ISAB response:Benefit – Supplementation has the potential

to forestall imminent extinction.Risk – Supplementation will cause a reduction

in natural spawning fitness to the target population.

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Council Question

Council: Can production (natural and artificial) be integrated to increase productivity?

ISAB response:

Yes, but at some cost to the capacity of the natural population to be self-sustaining.