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Experiences applying Experiences applying EcosimEcosim
in the Gulf of Alaskain the Gulf of Alaska
Sheila JJ Heymans, Sylvie GuénetteSheila JJ Heymans, Sylvie Guénette
Villy Christensen, Andrew TritesVilly Christensen, Andrew Trites
UBCFISHERIESCENTRE
INCOFISH WP 4 Meeting INCOFISH WP 4 Meeting Cape TownCape Town
11-16 September 200611-16 September 2006
AimsAims
• To evaluate how fishing and climate change have impacted the ecosystem resources of the Northeast Pacific;
• Used two systems: Aleutians and SE Alaska ~ species, notably Steller sea lions and other mammals, have different trajectories.
ProblemProblem
AleutiansAleutians
SEAKSEAK
Steller sea lion abundance
0
30,000
60,000
90,000
1956 1961 1966 1971 1976 1981 1986 1991 1996
Study areasStudy areas
Aleutian IslandsAleutian Islands
Southeast AlaskaSoutheast Alaska
Shelf east of 140oW0 - 1,000m depth
91,000 km2
170oW – 170oE0 - 500m depth
57,000 km2
MethodologyMethodology• Construct models of both ecosystems
(1963);• Driven by fisheries (i.e. using C/B); • Fitting: change vulnerabilities, feeding
time, P/B, etc.;• Estimate forcing function;• Correlate to environmental parameters;• Enter environmental function to fit
model.
Aleutians biomassAleutians biomass
0
500,000
1,000,000
1,500,000
2,000,000
1963 1968 1973 1978 1983 1988 1993 1998
Arrowtooth Atka Pollock
0
50,000
100,000
150,000
200,000
1963 1968 1973 1978 1983 1988 1993 1998
POP Sablefish
SE Alaska biomassSE Alaska biomass
0
100,000
200,000
300,000
400,000
500,000
600,000
1963 1968 1973 1978 1983 1988 1993 1998
Salmon Herring POP Sablefish
0
20,000
40,000
60,000
80,000
100,000
120,000
1963 1968 1973 1978 1983 1988 1993 1998
Halibut Pacific cod
Estimate environmental variationEstimate environmental variation
0.0
0.5
1.0
1.5
2.0
2.5
1963 1968 1973 1978 1983 1988 1993 1998
Aleutians SE Alaska
Known environmental indicesKnown environmental indices
-3
-2
-1
0
1
2
3
1963 1968 1973 1978 1983 1988 1993 199810
11
12
13
14
15
AO
I, A
LP
I, R
I
NP
I
Pacific Decadal Oscillation
PD
O
Environmental variationEnvironmental variation
0.7
0.8
0.9
1
1.1
1.2
1.3Ja
n-63
Jan-
66
Jan-
69
Jan-
72
Jan-
75
Jan-
78
Jan-
81
Jan-
84
Jan-
87
Jan-
90
Jan-
93
Jan-
96
Jan-
99
Jan-
02
Inverse PDO
PDO
Fitting the modelsFitting the models Aleutians - biomass
Biomass
PDO
Relative SS = 1
Environ.variation
Relative SS = 0.97
Fishing
Relative SS = 0.99
Steller sea lions
0
2,000
4,000
6,000
8,000
10,000
12,000
1963 1968 1973 1978 1983 1988 1993 1998
Atka mackerel
0
300,000
600,000
900,000
1,200,000
1963 1968 1973 1978 1983 1988 1993 1998
Adult pollock
0
150,000
300,000
450,000
600,000
750,000
1963 1968 1973 1978 1983 1988 1993 1998
Pacific Ocean perch
0
20,000
40,000
60,000
80,000
1963 1968 1973 1978 1983 1988 1993 1998
Sablefish
0
50,000
100,000
150,000
1963 1968 1973 1978 1983 1988 1993 1998
Arrowtooth flounder
0
10,000
20,000
30,000
40,000
50,000
1963 1968 1973 1978 1983 1988 1993 1998
Fitting the modelsFitting the models Aleutians - catch
Catch
Relative SS = 0.99
Fishing
Relative SS = 0.97
Environ.variation
Relative SS = 1
PDO
Forced catch
Steller sea lions
0
20
40
60
80
100
1963 1968 1973 1978 1983 1988 1993 1998
Atka mackerel
0
35,000
70,000
105,000
140,000
1963 1968 1973 1978 1983 1988 1993 1998
Adult pollock
0
35,000
70,000
105,000
140,000
1963 1968 1973 1978 1983 1988 1993 1998
Pacific Ocean perch
0
4,000
8,000
12,000
16,000
1963 1968 1973 1978 1983 1988 1993 1998
Arrowtooth flounder
0
1,500
3,000
4,500
6,000
7,500
1963 1968 1973 1978 1983 1988 1993 1998
Sablefish
0
1,500
3,000
4,500
1963 1968 1973 1978 1983 1988 1993 1998
Fitting the modelsFitting the modelsSE Alaska - biomass
Salmon
1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998
BiomassEnviron.variation
Relative SS = 1
PDO
Relative SS = 0.8
Fishing
Relative SS = 0.63
Steller sea lions
0
1,000
2,000
3,000
4,000
1963 1968 1973 1978 1983 1988 1993 1998
0
50,000
100,000
150,000
200,000
1963 1968 1973 1978 1983 1988 1993 1998
Herring
0
100,000
200,000
300,000
400,000
500,000
Pacific Ocean perch
0
50,000
100,000
150,000
200,000
250,000
1963 1968 1973 1978 1983 1988 1993 1998
Sablefish
0
20,000
40,000
60,000
80,000
100,000
1963 1968 1973 1978 1983 1988 1993 1998
Halibut
0
20,000
40,000
60,000
80,000
100,000
Fitting the modelsFitting the modelsSE Alaska - catch
Steller sea lions
0
1
2
3
4
5
6
7
0
15,000
30,000
45,000
1963 1968 1973 1978 1983 1988 1993 1998
10,000
20,000
30,000
40,000
0
1963 1968 1973 1978 1983 1988 1993 1998
Relative SS = 1
Environ.variation
Relative SS = 0.8
PDO
Catch
Forced catch
Relative SS = 0.63
Fishing
1963 1968 1973 1978 1983 1988 1993 1998
Salmon
0
70,000
140,000
210,000
280,000
350,000
1963 1968 1973 1978 1983 1988 1993 1998
Herring
Pacific Ocean perch
0
1963 1968 1973 1978 1983 1988 1993 1998
Sablefish
0
3,000
6,000
9,000
12,000
15,000
18,000
1963 1968 1973 1978 1983 1988 1993 1998
Halibut
3,500
7,000
10,500
14,000
Fishing
1000 0 1000 2000 3000 4000 Kilometers
N
Competitive Interactions
Fishing
Ocean Climate Change
Predation
Steller sea lionSteller sea lion declinedecline
Aleutian Islands
Guenette, Heymans, Christensen & Trites (in prep)
1960 1980 20000
10,000
20,000
30,000
40,000
Ab
un
da
nc
e
Competitive Interactions
Predation
ConclusionsConclusions
• Both external forces (fishing & climate change) have caused the changes in these two ecosystems;
• Fishing important for POP, herring and sablefish;• Environmental forces such as PDO combined with
fishing important for Steller sea lions, halibut and pollock;
• Sea lion decline explained by climate and predation• Unable to fit salmon as effects are larger scale than
these models.
Total systems throughputTotal systems throughput
3500
4500
5500
6500Ja
n-6
3
Jan
-66
Jan
-69
Jan
-72
Jan
-75
Jan
-78
Jan
-81
Jan
-84
Jan
-87
Jan
-90
Jan
-93
Jan
-96
Jan
-99
Jan
-02
Aleutians
SEAK
Network Analysis IndicesNetwork Analysis Indices
• Finn cycling index: relative amount of cycling in the ecosystem as a percentage of the total systems throughput (Finn 1976).
• Ascendency: indicator of the specialization and organization in the ecosystem (Ulanowicz, 1986).
• Redundancy: Internal flow overhead is an indication of the internal redundancy in the system (Mageau et al. 1998).
Information theoryInformation theory
Ulanowicz 1986
Organization & Specialization
Info
rmat
ion
CΦ A
Φ = C - A
Finn cycling indexFinn cycling index
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Jan-
63
Jan-
66
Jan-
69
Jan-
72
Jan-
75
Jan-
78
Jan-
81
Jan-
84
Jan-
87
Jan-
90
Jan-
93
Jan-
96
Jan-
99
Jan-
02
0.6
0.7
0.8
0.9
1.0
1.1
1.2A
leu
tian
s
SE
AK
0
0.3
0.6
0.9
1.2
1.5
Abs. diff. between value and 5 yr average
AscendencyAscendencyA
leu
tian
s
SE
AK
50
55
60
65
70
75
80
Jan-
63
Jan-
66
Jan-
69
Jan-
72
Jan-
75
Jan-
78
Jan-
81
Jan-
84
Jan-
87
Jan-
90
Jan-
93
Jan-
96
Jan-
99
Jan-
02
24
25
26
27
28
29
30
31
32
0
2
4
6
8
10
12
14
16
Abs. diff. between value and 5 yr average
0
20
40
60
80Ja
n-63
Jan-
65
Jan-
67
Jan-
69
Jan-
71
Jan-
73
Jan-
75
Jan-
77
Jan-
79
Jan-
81
Jan-
83
Jan-
85
Jan-
87
Jan-
89
Jan-
91
Jan-
93
Jan-
95
Jan-
97
Jan-
99
Jan-
01
Ascendency - AleutiansAscendency - Aleutians
Flow
Export
Respiration
0
4
8
12
16
Abs. diff. between value and 5 yr average
RedundancyRedundancy
32
33
34
35
36
37
38
Jan-
63
Jan-
66
Jan-
69
Jan-
72
Jan-
75
Jan-
78
Jan-
81
Jan-
84
Jan-
87
Jan-
90
Jan-
93
Jan-
96
Jan-
99
Jan-
02
44
45
46
47
48
49A
leu
tian
s
SE
AK
0
1
2
3
4
Abs. diff. between value and 5 yr average
ConclusionsConclusions
• Effects of environmental variation is seen in the total systems throughput, ascendency and redundancy;
• Finn cycling index shows less direct effects and might be more useful as index of emergent effects;
• Change from the running average increased after regime shift in most indices;
• Difference less in SEAK than in AI;• AI: largest fluctuations in respiration for both
ascendency and overhead.
AcknowledgementsAcknowledgements
• Support from NOAA through the North Pacific Universities Marine Mammal Research Consortium and the North Pacific Marine Science Foundation
• Colleagues from DFO, ADF&G, NMFS, MMU
• Carl Walters, Steve Martell