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AMCC/WWF Roundtable Discussion on Climate Change. How Might Fish Respond to a Warming Bering Sea – The Physiological Context. by Jeffrey Short, Ph.D. Science Advisor, Alaska Marine Conservation Council. Anchorage, Alaska June 27, 2006. A Cold-Blooded Response To Global Warming. - PowerPoint PPT Presentation
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AMCC/WWF Roundtable Discussion on
Climate Change
How Might Fish Respond to a Warming Bering Sea – The Physiological Context
byJeffrey Short, Ph.D.
Science Advisor, Alaska Marine Conservation Council
Anchorage, AlaskaJune 27, 2006
A Cold-Blooded Response To Global Warming.........
Growth Rate vs Temperature & Food
Development Time vs Temperature
Sub-Arctic Ocean Production Cycle
Thermal Constraints on Population Size
Warming-Induced Northward Range Extension: Freshwater Fish
Juvenile Pollock: Metabolic Demand vs Weight
0.00
0.05
0.10
0.15
0.20
0 20 40 60 80 100 120
Weight (g)
kJ/g
*d
Juvenile Pollock: Starvation Time vs Weight
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120
Weight (g)
Day
s
Starvation Time: 2 C Temperature Rise
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120
Weight (g)
Day
s
Trade-offs Between Foraging, Structural and Storage Energy
Proportion of Respiratory Demand
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100 150 200 250 300
Length (mm)
Structure
Storage
YOY Juvenile
Bering Sea Food Web: 1980s
Food-Web Stresses
Shrinking Primary Production
Increased Apex Predators
Increased Respiration Demand
Ecosystem Resiliency – What Do We Want?
Maintain Food-Web Structure?
Promote Diversity?
Promote Fishing Opportunities?
Avoid Species Extinctions?
Thermal Constraints on Population Size
Cycles Reflect Change
Bioenergetics 101Energy content of fish varies seasonally
4
6
8
10
12
Energy Density
2002 2003 20042001
Energy Phenology in Herring
Spring Winter Spring WinterSpring Winter
Energy Density
Cycles Reflect Change in Structural and Storage Energy
Male Pacific herring protein & lipid content
20
30
40
50
60
70
0 10 20 30 40 50
Week (Sept. 27, 2004 to Sept. 9, 2005)
Mea
n p
erce
nt
of
dry
m
ass
(1 S
E)
Protein
Lipid
Nutritional Analysis Reveals Differences in Habitat Quality
Energy lost overwinter by subadult pollock (lth = 161 mm)
0
5
10
15
20
25
30
35
40
45
50
Total Structure Storage
Source of Energy
kJo
ule
s Fred. Sound
Lynn Canal
Nutritional Analysis Reveals Energy Sources Depend on Age
kJoules
Total EnergyLipidProteinMarDecMarDecMarDec
40
30
20
10
0
Total EnergyLipidProteinMarDecMarDecMarDec
Age = 0 Age = 1
Energy sources consumed by capelin over winter
63% contrib.
31% contrib.
23% loss
100% Contrib.
29% loss
No contrib.
Cycles Reflect Change
Cycles Reflect Change
Cycles Reflect Change
Cycles Reflect Change
Cycles Reflect Change
