1 Independent Scientific Advisory Board June 12, 2003 A Review of Salmon and Steelhead...
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Transcript of 1 Independent Scientific Advisory Board June 12, 2003 A Review of Salmon and Steelhead...
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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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6
10
15
86
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3 2 1 0 1 2
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Adult Production from Breeding
Fre
qu
en
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
0.0
1.0
2.0
3.0
4.0
1974 1979 1984 1989 1994
Brood Year
Ln
(R)
JohnDayUmatillaJoseph
Productivity Variation in Oregon Steelhead
17Summer Chinook Aerial Redd Counts
0
50
100
150
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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
Red
ds
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
Nat
ura
l sp
awn
ing
adu
lts
of n
atu
ral o
rigi
n
Supplemented
Nat
ura
l sp
awn
ing
adu
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of n
atu
ral o
rigi
n
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Quantifying Benefits and Risks:Performance indicators and standards - Reference Streams
Demographically Successful Supplementation
Supplemented
Reference
Nat
ura
l sp
awn
ing
adu
lts
of n
atu
ral o
rigi
n
Supplemented
Reference
Unsuccessful Supplementation
Nat
ura
l sp
awn
ing
adu
lts
of n
atu
ral o
rigi
n
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)
0
100
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300
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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
0.0
10.0
20.0
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40.0
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70.0
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Run Year
Pro
po
rtio
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f P
op
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tio
n
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.