Transcript Fisheries and Marine Mammal interaction in Southeastern

Experiences applying
Ecosim
in the Gulf of Alaska
Sheila JJ Heymans, Sylvie Guénette
Villy Christensen, Andrew Trites
INCOFISH WP 4 Meeting
Cape Town
11-16 September 2006
UBC
FISHERIES
CENTRE
Aims
• 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.
Problem
90,000
Steller sea lion abundance
Aleutians
60,000
30,000
SEAK
0
1956 1961 1966 1971 1976 1981 1986 1991 1996
Study areas
Southeast Alaska
Aleutian Islands
170oW – 170oE
0 - 500m depth
57,000 km2
Shelf east of 140oW
0 - 1,000m depth
91,000 km2
Methodology
• 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 biomass
2,000,000
1,500,000
1,000,000
500,000
0
1963
1968
1973
1978
Arrowtooth
1983
Atka
1988
1993
1998
Pollock
200,000
150,000
100,000
50,000
0
1963
1968
1973
1978
POP
1983
1988
Sablefish
1993
1998
SE Alaska biomass
600,000
500,000
400,000
300,000
200,000
100,000
0
1963
1968
1973
Salmon
1978
Herring
1983
POP
1988
1993
1998
Sablefish
120,000
100,000
80,000
60,000
40,000
20,000
0
1963
1968
1973
1978
Halibut
1983
Pacific cod
1988
1993
1998
Estimate environmental variation
2.5
2.0
1.5
1.0
0.5
Aleutians
SE Alaska
0.0
1963
1968
1973
1978
1983
1988
1993
1998
Known environmental indices
Pacific Decadal Oscillation
15
2
14
1
13
0
12
-1
11
-2
-3
1963
10
1968
1973
1978
1983 1988
1993
1998
NPI
AOI, ALPI, RI
PDO
3
0.7
Jan-02
Jan-99
Jan-96
Jan-93
Jan-90
Jan-87
Jan-84
Jan-81
Jan-78
Jan-75
Jan-72
Jan-69
1.2
Jan-66
Jan-63
Environmental variation
1.3
Inverse PDO
1.1
1
0.9
PDO
0.8
Fitting the models
Biomass
PDO
Fishing
Environ.
variation
Aleutians - biomass
Steller sea lions
12,000
Atka mackerel
1,200,000
10,000
900,000
8,000
6,000
600,000
4,000
300,000
2,000
0
0
1963
1968
1973
1978
1983
1988
1993
1998
1963
1968
Adult pollock
750,000
40,000
450,000
30,000
300,000
20,000
150,000
10,000
1978
1983
1988
1993
1998
Arrowtooth flounder
50,000
600,000
1973
0
0
1963
1968
1973
1978
1983
1988
1993
1963
1998
1968
1973
Pacific Ocean perch
80,000
1978
1983
1988
1993
1998
Sablefish
150,000
60,000
Relative SS = 1
Relative SS = 0.99
100,000
40,000
50,000
20,000
0
0
1963
1968
1973
1978
1983
1988
1993
1998
1963
1968
1973
1978
1983
1988
1993
1998
Relative SS = 0.97
Fitting the models
Aleutians - catch
Steller sea lions
100
Atka mackerel
140,000
80
105,000
60
70,000
40
20
Forced
catch
Catch
PDO
Fishing
Environ.
variation
35,000
0
1963
1968
1973
1978
1983
1988
1993
1998
0
1963
Adult pollock
1968
1973
1978
1983
1988
1993
1998
Arrowtooth flounder
7,500
140,000
6,000
105,000
4,500
70,000
3,000
1,500
35,000
0
0
1963
1963
1968
1973
1978
1983
1988
1993
1968
1973
1978
1983
1988
1993
1998
1998
Pacific Ocean perch
Sablefish
4,500
16,000
12,000
3,000
8,000
1,500
Relative SS = 1
4,000
0
0
1963
1968
1973
1978
1983
1988
1993
1998
1963
1968
1973
1978
1983
1988
1993
1998
Relative SS = 0.99
Relative SS = 0.97
Fitting the models
SE Alaska - biomass
Salmon
Steller sea lions
4,000
200,000
3,000
150,000
2,000
100,000
1,000
50,000
Biomass
Environ.
variation
PDO
Fishing
0
0
1963
1968
1973
1978
1983
1988
1993
1998
1963
1968
1973
Pacific Ocean perch
250,000
60,000
100,000
40,000
50,000
20,000
500,000
1988
1993
1998
1993
1998
80,000
150,000
0
1963
1983
Sablefish
100,000
200,000
1978
1968
1973
1978
1983
1988
1993
1998
Herring
0
1963
1973
1978
1983
1988
Halibut
100,000
400,000
80,000
300,000
60,000
200,000
40,000
100,000
20,000
0
1963 1968 1973 1978 1983 1988 1993 1998
1968
Relative SS = 1
Relative SS = 0.8
0
1963
1968
1973
1978
1983
1988
1993
1998
Relative SS = 0.63
Fitting the models
SE Alaska - catch
Steller sea lions
7
Salmon
350,000
6
280,000
Fishing
5
210,000
4
3
Forced
catch
Catch
Environ.
variation
PDO
140,000
2
70,000
1
0
0
1963
1968
1973
1978
1983
1988
1993
1998
Pacific Ocean perch
40,000
1963
1968
1973
1978
1983
1988
1993
1998
Sablefish
18,000
15,000
30,000
12,000
20,000
9,000
6,000
10,000
3,000
0
0
1963
1968
1973
1978
1983
1988
1993
1998
Herring
45,000
1963
1968
1973
1978
1983
1988
1993
1998
Halibut
14,000
10,500
Relative SS = 1
Relative SS = 0.8
30,000
7,000
15,000
3,500
0
0
1963
1968
1973
1978
1983
1988
1993
1998
1963
1968
1973
1978
1983
1988
1993
1998
Relative SS = 0.63
Steller sea lion decline
Fishing
Aleutian Islands
Predation
Abundance
40,000
Competitive Interactions
30,000
20,000
10,000
0
1960
Ocean Climate
Change
1980
2000
Guenette, Heymans, Christensen & Trites (in prep)
Conclusions
• 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.
Jan-02
Jan-99
Jan-96
Jan-93
Jan-90
Jan-87
Jan-84
Jan-81
Jan-78
Jan-75
Jan-72
Jan-69
Jan-66
Jan-63
Total systems throughput
6500
Aleutians
5500
4500
SEAK
3500
Network 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 theory
A
Φ
C
Organization & Specialization
Φ=C-A
Ulanowicz 1986
1.5
1.2
0.9
0.6
0.3
0
Abs. diff. between value and 5 yr average
SEAK
0.6
Jan-02
0.5
Jan-99
0.7
Jan-96
1.0
Jan-93
0.8
Jan-90
1.5
Jan-87
0.9
Jan-84
2.0
Jan-81
1.0
Jan-78
2.5
Jan-75
1.1
Jan-72
3.0
Jan-69
1.2
Jan-66
3.5
Jan-63
Aleutians
Finn cycling index
50
16
14
12
10
8
6
4
2
0
Abs. diff. between value and 5 yr average
Jan-02
Jan-99
Jan-96
Jan-93
Jan-90
Jan-87
Jan-84
Jan-81
Jan-78
Jan-75
Jan-72
Jan-69
Jan-66
Jan-63
Aleutians
80
75
70
29
65
28
60
27
26
55
25
24
SEAK
Ascendency
32
31
30
0
16
12
8
4
0
Abs. diff. between value and 5 yr average
Jan-01
Jan-99
Jan-97
Jan-95
Jan-93
Jan-91
Jan-89
Jan-87
Jan-85
Jan-83
Jan-81
Jan-79
Jan-77
Jan-75
Jan-73
Jan-71
Jan-69
Jan-67
20
Jan-65
40
Jan-63
Ascendency - Aleutians
80
60
Respiration
Export
Flow
32
4
3
2
1
0
Jan-63
Abs. diff. between value and 5 yr average
Jan-02
Jan-99
Jan-96
Jan-93
Jan-90
Jan-87
Jan-84
Jan-81
Jan-78
Jan-75
Jan-72
Jan-69
Jan-66
Aleutians
Redundancy
37
35
46
34
33
45
44
SEAK
38
49
48
36
47
Conclusions
• 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.
Acknowledgements
• 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