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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
Upwelling winds at 48N
Amphitrite Pt SST
Oct Feb Jun
Oct Feb Jun
Oct Feb Jun Jan May Sep
Insolation
The predictable part: seasonal rhythms
Oct Feb Jun
Skagit
Puyallup
Skokomish
Oct Feb Jun
Oct Feb Jun
Puget Sound Precip
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
70 75 80 85 90 95 00
70 75 80 85 90 95 00
70 75 80 85 90 95 00
70 75 80 85 90 95 00
70 75 80 85 90 95 00
70 75 80 85 90 95 00
Monthly Puget Sound Precip
Daily Upwelling winds
Monthly Amphitrite Pt SST Skokomish
Puyallup
Skagit
upwelling food webs in our coastal ocean: the California Current
Cool water, weak stratificationhigh nutrients, a productive “subarctic” food-chain with abundant forage fish and few warm water predators
Warm stratified ocean, fewnutrients, low productivity “subtropical” food web, a lack of forage fish and abundant predators
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 climatePart 1: GG Emissions and concentrations
IPCC Summary for Policymakers 2001
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
– floodingNatural 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
0.02
0.04
0.06
0.08
0.1
0.12
0.1419
70
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
Return Year
Surv
ival
Question: WHY?
leading hypothesis: changes in ocean conditions impact the entire marine food-web
“Ocean Conditions Model” hindcasts for 1948-1968
Washington-Oregon-Californiacoho landings
Cat
ch in
mil
lion
s of
coh
o
2
4
6
OP
I survival rate (%)
2
4
6
8
10
Ocean conditions appear to be an important piece of the OPI hatchery coho story; they may or may not explain an important part of 48-68 coho landings.
The Doomsday Clock 2001
Oosterhout and Mundy, 2001
Brood year
Wil
d S
paw
ners
1999 2020
Their approach amounts to a “persistence forecast” based on expectations for continued “non-replacement productivity” observed in the 1985-1994 period
Hatcheries: a fish is a fish
Spring transition date
Mar Apr May June July
Wild coho smolt migration
Hatchery coho releases
Ex: smolt migration timing in wild and hatchery coho