Transcript Document

A Climate Angle on Uncertainty
in Salmon Recovery Scenarios
Nate Mantua Ph D
Joint Institute for the Study of the
Atmosphere and Oceans
University of Washington
Key Points
• Spatial variability:
– Complex topography in PS region yields complex
spatial patterns of hydro-climate
• Temporal variability:
– Climate and weather variations cause habitat variations
at time scales from days to decades
• Salmon in the future?
– Don’t buy into long-term climate predictions!
– Careful considerations of climate uncertainty will help
paint more realistic pictures of the true uncertainty in
recovery scenarios
The predictable part: seasonal rhythms
Puget Sound Precip
Insolation
Oct
Jan
May
Feb
Jun
Upwelling winds at 48N
Oct
Feb
Jun
Amphitrite Pt SST
Oct
Feb
Sep
Jun
The predictable part: seasonal rhythms
Puget Sound Precip
Oct
Feb
Skagit
Jun
Oct
Feb
Jun
Puyallup
Oct
Feb
Jun
Skokomish
Oct
Feb
Jun
Why is climate important?
• salmon have successfully colonized and
occupied each stream type (snow-melt, runoff,
and everything in-between)
– Different stocks employ distinct life history
behaviors tuned to the predictable seasonal rhythms
– “stability” and “variability” of seasonal climate and
environmental changes have obviously played a role
in shaping salmon behavior at the stock level
Variations on the seasonal rhythms
Monthly Puget Sound Precip
70
75
80
85
90
95
Skagit
00
75
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90
95
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75
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85
90
80
85
90
95
00
70
75
80
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95
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Skokomish
Monthly Amphitrite Pt SST
70
75
Puyallup
Daily Upwelling winds
70
70
95
00
70
75
80
Upwelling impacts (August 2000)
temperature
Chlorophyll
upwelling food webs in our coastal ocean:
the California Current
Cool water, weak stratification
high nutrients, a productive
“subarctic” food-chain with
abundant forage fish and few
warm water predators
Warm stratified ocean, few
nutrients, low productivity
“subtropical” food web, a
lack of forage fish and
abundant predators
Alaska and PNW
salmon production
are out of phase
(Hare et al 1999, Fisheries)
future climate?
TWO STREAMS OF UNCERTAINTY:
1. Natural Variability (El Niño, PDO, other)
2. Anthropogenic change
•
•
Future emissions and greenhouse gas
concentrations
Climate system response to increased
concentrations of greenhouse gases
•
future climate change is now assessed with a range
of models and scenarios …
Uncertainty in future climate
Part 1: GG Emissions and concentrations
IPCC Summary for Policymakers 2001
Temperature Change (C)
Uncertainty in future climate
Part 2: Climate Sensitivity
What might climate change look
like in the Northwest?
• We looked at 7 scenarios of
future climate from climate
models
• Averages of 7 scenarios,
compared to 20th century:
– 2F warmer by 2020s
– 4F warmer by 2050s
– slightly wetter
• Winters wetter
• Summers ???
20th century
average
Impacts of hydrologic changes
• Less snow, earlier melt means less water in summer
–
–
–
–
irrigation
urban uses
fisheries protection
energy production
• More water in winter
– energy production
– flooding
Natural Columbia River flow at the Dalles, OR.
recommendations
• Consider climate as a source of habitat
uncertainty
– develop recovery scenarios based on past
climate records and/or future scenarios, perhaps
bounded by “best” and “worst” cases
• Consider potential roles for stock diversity
– explore a range of functional relationships
between habitat state and survival
– examine the importance of straying between
different population segments
OPI (hatchery) coho marine survival
0.14
Question: WHY?
0.12
leading hypothesis:
changes in ocean
conditions impact the
entire marine foodweb
0.08
0.06
0.04
0.02
Return Year
1998
1996
1994
1992
1990
1988
1986
1984
1982
1980
1978
1976
1974
1972
0
1970
Survival
0.1
“Ocean Conditions Model” hindcasts for 1948-1968
0.16
Ocean conditions appear
to+/- 1be
S.E. an important piece of
Washington-Oregon-California
the OPI hatchery coho
coho landings
story; they may or may not
explain an important part
of 48-68 coho landings.
6
4
2
6
0.12
0.1
10
OPI marine survival
8
0.14
8
0.08
6
4
0.06
4
0.04
2
2
0.02
WOC Coho production
Year
GAM modelled survival
Observed survival
GAM forecast survival
GAM hindcast survival
2001
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
1971
1969
1967
1965
1963
1961
1959
1957
1955
1953
1951
1949
0
1947
0
OPI survival rate (%)
- millions of fish
of coho
in millions
Catchproduction
10
Wild Spawners
The Doomsday Clock 2001
Their approach amounts to a
“persistence forecast” based on
expectations for continued “nonreplacement productivity”
observed in the 1985-1994 period
Brood year
1999
2020
Oosterhout and Mundy, 2001
Hatcheries: a fish is a fish
Ex: smolt migration timing in wild and hatchery coho
Spring transition date
Wild coho smolt migration
Hatchery coho releases
Mar
Apr
May
June
July
ocean temperature deviations from normal
February-April 2002