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Fisheries Oceanography

Fisheries Oceanography. SST anomalies off Peru coastline. ENSO impacts on pelagic fishes: variable catch reductions (Peru). A. Bertrand. 12. 8. Catch (M. tons). El Nino. 4. 0. 1950. 1960. 1970. 1980. 1990. (Yánez et al. 1992). A. Bertrand. Space. Large scale forcing.

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Fisheries Oceanography

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  1. Fisheries Oceanography

  2. SST anomalies off Peru coastline

  3. ENSO impacts on pelagic fishes: variable catch reductions (Peru) A. Bertrand 12 8 Catch (M. tons) El Nino 4 0 1950 1960 1970 1980 1990 (Yánez et al. 1992)

  4. A. Bertrand Space Large scale forcing Inter-decadal regime Ocean ENSO strength and duration Stock conditionbefore ENSO Basin Fishery pressure Small scale forcing Regional Adapted reproduction Local Upwelling Local Time Day Month Season Year Decade Inter-annual Spatio-temporal scales of effects on peruvian pelagic fisheries

  5. Pacific Decadal Oscillations

  6. ENSO and pelagic fisheries: regime shift Chavez et al. 2003

  7. Clupeidae American shad Alosa sapidissima Engraulidae baelama anchovy Thryssa baelama

  8. A. Bertrand (Chavez et al. 2002)

  9. A. Bertrand (Chavez et al. 2002)

  10. Pacific Decadal Oscillation Warm Phase Cool Phase Wintertime Wind (arrows) and Sea SurfaceTemp (colors) - Affect the N. Pacific, with secondary signatures in the tropics (opposite for ENSO)

  11. Pacific Decadal Oscillation(PCA of N. Pacific SST) 20-30 year duration

  12. A. Bertrand Chavez et al 2003

  13. A. Bertrand Chavez et al 2003

  14. Humans as Top Predator

  15. Global Trend in Landings 100 EEZs Claims million tonnes) 50 Production ( 1800 1840 1880 1920 1960 2000 Year

  16. A. Bertrand Expansion of fisheries Non-registered catches (Pauly et al., 2002)

  17. A. Bertrand Expansion of fisheries Non-registered catches (Pauly et al., 2002)

  18. Trawling

  19. Humans as “engineer species” • Trawling disrupts sea bottom…… • Trawling ecosystem effects: • Decrease of spatial complexity • Decrease of target and bycatch species • Increase of scavenger species • Overall loss of biodiversity (macro-organism level)

  20. Un-trawled Trawled

  21. Trawling Impact Un-trawled Area Trawled Area (bottom sonar images)

  22. Bycatch of unwanted species

  23. Turtle Excluder Device (TED)

  24. Trawling frequency by german vessels between 1993 & 1996 P. Cury (Rijnsdorp 1997)

  25. Marine Protected Areas No Trawling Area Gulf of Maine

  26. Gillnetting

  27. Bycatch of unwanted species

  28. A. Bertrand Expansion of fisheries Non-registered catches (Pauly et al., 2002)

  29. Purse seining

  30. Schooling behavior

  31. Bycatch of unwanted species

  32. A. Bertrand Expansion of fisheries Non-registered catches (Pauly et al., 2002)

  33. Longlining

  34. Bycatch of unwanted species

  35. A. Bertrand Expansion of fisheries Non-registered catches Why steady increase? (Pauly et al., 2002)

  36. Catches per 100 hooks (Japanese fleet) 1952 1958 1964 1980 Myers & Worm, 2003

  37. Shark Populations NE Atlantic Baum et al. 2003

  38. Fishing Down the Food Web

  39. Fishery induced changes in world fish composition

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