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Overview
Modeling to date:– Distribution of mortality– Achieving improvements with specific actions
Building scenarios Dealing with uncertainty – some ideas
Snake River Spring/Summer Chinook Life Cycle
2 spawners 4,000-5,000 eggs
120-151 1-year-oldsto Lower Granite Dam
95-119 Migrants Below Bonneville Dam (77%
transported, 23% in River)
4-5 Youngsters To 2nd Birthday (Estuary & Ocean)
2-3 Adults return tomouth of Columbia
1-1.4 Migrants return to spawning grounds
0.50
0.60
0.70
0.80
0.90
1.00
1.10
Lower C
olum
bia
Upper C
olum
bia S
pr
Snake
River
Spr/S
um
Snake
River
Fal
l
Upper W
illam
ette
Colum
bia R
iver
Chum
Lower C
olum
bia
Mid
dle C
olum
bia
Upper C
olum
bia
Snake
River
Upper W
illam
ette
Po
pu
lati
on
Gro
wth
Rat
e
Hatchery fish reproductive success = 1
Hatchery fish reproductive success = 0
Rate of population change – Accounting for hatchery fish
Chinook Steelhead
Improvements to hydropower system
Past – passage improvements Future options
– Passage improvements» Flow and spill measures
– Dam breaching
Past vs. current passage survival
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Current High harvest,improved hydro
Low harvest,unimproved
hydro
High harvest,unimproved
hydro
An
nu
al p
op
ula
tio
n g
row
th r
ate
Snake River spr/sum chinook
Option 1 – anticipated changes with passage improvement
Snake River Fall Chinook High Needed Change
0.8
1.0
1.2
1.4
1.6
1.8
0.00 0.05 0.10 0.15 0.20
Direct and Indirect (D=.24) Hydrosystem Survival (Juvenile * Adult)
Pro
po
rtio
na
l Ch
an
ge
In O
the
r L
ife
Sta
ge
Su
rviv
al
100% Extinction Risk in 100 Yrs and 0% in 24 Yrs 5% Extinction Risk In 100 Yrs
50% Recovery in 48 Years 50% Recovery in 100 Years
Base (1980-96 Returns) Current
Hydro RPA
Harvest – maximum benefits
0.500 0.600 0.700 0.800 0.900 1.000 1.100 1.200 1.300 1.400
L. Columbia ChinookU. Columbia Spr Chinook
Snake R. Spr/Sum ChinookSnake R. Fall ChinookU. Willamette Chinook
L. Columbia Winter SteelheadMid Columbia Steelhead
U. Columbia SteelheadSnake R. Steelhead
U. Willamette Steelhead
Population Growth Rate
Maximum Population Growth Rate (Zero Harvest) Current PopulationGrowth Rate
Sensitivity Test – Standard reductions in mortality
0
0.1
0.2
0.3
0.4
0.5
freshwater proportiontransported
downstreamsurvival
estuary/earlyocean
adult ocean upstreammigration
harvest
% c
han
ge
in l
amb
da
Snake River Spring/Summer Chinook Life Cycle
2 spawners 4,000-5,000 eggs
120-151 1-year-oldsto Lower Granite Dam
95-119 Migrants Below Bonneville Dam (77%
transported, 23% in River)
4-5 Youngsters To 2nd Birthday (Estuary & Ocean)
2-3 Adults return tomouth of Columbia
1-1.4 Migrants return to spawning grounds
Survival vs. sedimentation
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60
Percentage Fine Sediments
Em
bry
o S
urv
ival
(%
)
Steelhead
Chinook
Hatchery – Genetic concerns
Inadvertent selection due to hatchery practices reduces fitness of hatchery fish. Interbreeding of hatchery and wild fish may affect fitness of wild fish as well.– Domestication – seen in as little as a single
generation– Stock transfers
Hatchery – Ecological concerns
10 20 30 40 5010 20 30 40 50-3
-2
-1
0
1
2
Per
cent
sur
viva
l wild
chi
nook
(lo
g)
Number of hatchery spring chinook released (millions)
r2 = 0.06 r2 = 0.73
Average Ocean Productivity Poor Ocean Productivity
Building scenarios
Combinations of actions – when one isn’t enough
Interactions between actions Continuing degradation in habitat/other
environmental factors
Major areas of uncertainty
Hatchery fish masking – what is the TRUE population status?
Interactions between life stages – does survival/growth/experience in one stage affect survival/fitness in another?
Impacts of particular actions
Snake River Spring/Summer Chinook Life Cycle
2 spawners 4,000-5,000 eggs
120-151 1-year-oldsto Lower Granite Dam
95-119 Migrants Below Bonneville Dam (77%
transported, 23% in River)
4-5 Youngsters To 2nd Birthday (Estuary & Ocean)
2-3 Adults return tomouth of Columbia
1-1.4 Migrants return to spawning grounds
Some possible approaches
Different questions –– What actions (or areas) are important
REGARDLESS of the potential future?– Are there easy actions that might be useful for
bet-hedging against an unlikely future?– Which pieces of information would be most
important to have (would help us reduce our uncertainty)?
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