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Experiences applying Ecosim in the Gulf of Alaska

UBC FISHERIES CENTRE. 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. Aims.

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Experiences applying Ecosim in the Gulf of Alaska

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  1. UBC FISHERIES CENTRE Experiences applying Ecosimin the Gulf of Alaska Sheila JJ Heymans, Sylvie Guénette Villy Christensen, Andrew Trites INCOFISH WP 4 Meeting Cape Town 11-16 September 2006

  2. 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.

  3. Steller sea lion abundance 90,000 60,000 30,000 0 1956 1961 1966 1971 1976 1981 1986 1991 1996 Problem Aleutians SEAK

  4. Study areas Shelf east of 140oW 0 - 1,000m depth 91,000 km2 Southeast Alaska Aleutian Islands 170oW – 170oE 0 - 500m depth 57,000 km2

  5. 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.

  6. Aleutians biomass

  7. SE Alaska biomass

  8. Aleutians SE Alaska Estimate environmental variation 2.5 2.0 1.5 1.0 0.5 0.0 1963 1968 1973 1978 1983 1988 1993 1998

  9. Pacific Decadal Oscillation AOI, ALPI, RI NPI PDO Known environmental indices 3 15 2 14 1 13 0 12 -1 11 -2 -3 10 1963 1968 1973 1978 1983 1988 1993 1998

  10. Inverse PDO PDO Environmental variation 1.3 1.2 1.1 1 0.9 0.8 0.7 Jan-02 Jan-75 Jan-78 Jan-81 Jan-84 Jan-87 Jan-90 Jan-93 Jan-63 Jan-66 Jan-69 Jan-72 Jan-96 Jan-99

  11. Fishing Environ. variation Steller sea lions Atka mackerel 1,200,000 12,000 10,000 900,000 8,000 PDO 6,000 600,000 4,000 300,000 2,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Adult pollock Arrowtooth flounder 750,000 50,000 600,000 40,000 450,000 30,000 20,000 300,000 10,000 150,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Pacific Ocean perch Sablefish 80,000 150,000 Relative SS = 1 60,000 100,000 40,000 Relative SS = 0.99 50,000 20,000 Relative SS = 0.97 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Fitting the modelsAleutians - biomass Biomass

  12. Forced catch Fishing Steller sea lions Atka mackerel Environ. variation 100 140,000 80 105,000 60 70,000 40 PDO 20 35,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Adult pollock Arrowtooth flounder 7,500 140,000 6,000 105,000 4,500 70,000 3,000 1,500 35,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Pacific Ocean perch Sablefish 4,500 16,000 12,000 3,000 8,000 Relative SS = 1 1,500 4,000 0 0 Relative SS = 0.99 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Relative SS = 0.97 Fitting the modelsAleutians - catch Catch

  13. Biomass Fishing Environ. variation PDO Relative SS = 1 Relative SS = 0.8 Relative SS = 0.63 Fitting the modelsSE Alaska - biomass Salmon Steller sea lions 4,000 200,000 3,000 150,000 100,000 2,000 50,000 1,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Pacific Ocean perch Sablefish 250,000 100,000 200,000 80,000 150,000 60,000 100,000 40,000 50,000 20,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Halibut Herring 100,000 500,000 80,000 400,000 300,000 60,000 200,000 40,000 100,000 20,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998

  14. Forced catch Fishing Environ. variation Salmon 350,000 280,000 210,000 PDO 140,000 70,000 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Sablefish Pacific Ocean perch 18,000 15,000 12,000 9,000 6,000 3,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998 Herring Halibut 14,000 Relative SS = 1 10,500 7,000 Relative SS = 0.8 3,500 Relative SS = 0.63 Fitting the modelsSE Alaska - catch Catch Steller sea lions 7 6 5 4 3 2 1 0 40,000 30,000 20,000 10,000 45,000 30,000 15,000 0 0 1963 1968 1973 1978 1983 1988 1993 1998 1963 1968 1973 1978 1983 1988 1993 1998

  15. Fishing Fishing Predation Predation 40,000 Competitive Interactions Competitive Interactions 30,000 Abundance 20,000 10,000 Ocean Climate Change 0 1960 1980 2000 Steller sea liondecline Aleutian Islands Guenette, Heymans, Christensen & Trites (in prep)

  16. 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.

  17. Total systems throughput 6500 Aleutians 5500 4500 SEAK 3500 Jan-02 Jan-75 Jan-78 Jan-81 Jan-84 Jan-87 Jan-90 Jan-93 Jan-99 Jan-63 Jan-66 Jan-69 Jan-72 Jan-96

  18. 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).

  19. Information A C Φ Information theory Organization & Specialization Φ = C - A Ulanowicz 1986

  20. Abs. diff. between value and 5 yr average Finn cycling index 3.5 1.2 3.0 1.1 2.5 1.0 SEAK Aleutians 0.9 2.0 1.5 0.8 1.0 0.7 0.5 0.6 Jan-75 Jan-78 Jan-81 Jan-84 Jan-87 Jan-90 Jan-93 Jan-96 Jan-63 Jan-66 Jan-69 Jan-72 Jan-99 Jan-02

  21. Abs. diff. between value and 5 yr average Ascendency 80 32 31 75 30 70 29 SEAK 65 28 Aleutians 27 60 26 55 25 50 24 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

  22. Respiration Export Flow Abs. diff. between value and 5 yr average Ascendency - Aleutians 80 60 40 20 0 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-63 Jan-65 Jan-95 Jan-97 Jan-99 Jan-01

  23. Abs. diff. between value and 5 yr average Redundancy 38 49 37 48 36 47 35 46 Aleutians SEAK 34 45 33 32 44 Jan-78 Jan-81 Jan-84 Jan-87 Jan-90 Jan-93 Jan-96 Jan-75 Jan-63 Jan-66 Jan-69 Jan-72 Jan-99 Jan-02

  24. 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.

  25. 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

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