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Fisheries

Fisheries. Fish as Food Commercial Fisheries Trends in World Fisheries Solutions?. Commercial Fisheries. Traps Trawls Purse seines Gillnets Longlines etc…. Purse seining. Trawling. Fish size-selective grid Cod Fishery - Norway. Gillnetting. Longlining.

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Fisheries

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  1. Fisheries Fish as Food Commercial Fisheries Trends in World Fisheries Solutions?

  2. Commercial Fisheries • Traps • Trawls • Purse seines • Gillnets • Longlines • etc…

  3. Purse seining

  4. Trawling

  5. Fish size-selective grid Cod Fishery - Norway

  6. Gillnetting

  7. Longlining

  8. Technological Improvement in Fisheries

  9. Tuna catches under floating objects

  10. Corrected Non corrected World Fishing Fleet Capacity 40 30 GrossRegisteredTonnage (106tons) 20 10 0 1990 2000 1970 1980 1960

  11. 100 Capture 80 60 Million tonnes 40 20 mariculture 0 2000 1990 1950 1960 1970 1980 Production of Marine Fisheries

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

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

  14. Phase IV - Senescent Development Phases of World Fisheries 100% 90% 80% 70% Phase III - 60% Mature Percentageofresources 50% 40% Phase II - Developing 30% 20% Phase I - 10% Undeveloped 0% 1951 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993

  15. State of Fish Stocks 1999 Recovering Depleted Overexploited Fully exploited Moderately exploited Undeveloped 0% 10% 20% 30% 40% 50%

  16. Trends in States of Fish Stocks 60% Fully Fished 50% 40% Moderately fished: U+M 30% 20% Overfished: O+D+R 10% 0% 1970 1975 1980 1985 1990 1995 2000 2005

  17. Ratio between Present & Historical Landings 1 . Antarctic 0.14 ANT 2. Atlantic, Southeast 0.39 ASE 3. Pacific, Southeast 0.43 PSE 4. Atlantic, Northwest 0.44 ANW 5. Atlantic, Western Central 0.71 ACW 6. Pacific, Eastern Central 0.73 PEC 7. Med it . & Black Sea 0.81 MBS 8. Pacific, Northeast 0.83 PNE 9. Atlantic Southwest 0.86 ASW 10. Atlantic Eastern Central 0.87 AEC 11. Atlantic Northeast ANE 0.92 12. Indian Western 0.94 IW 13. Pacific Central Western 14. Pacific Southwest PCW 1.00 15. Pacific Northwest PSW 1.00 16. Indian Eastern PNW 1.00 1.00 IE 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

  18. Maximum Sustainable Yield Population Size (N) = Growth = Maximum Sustainable Yield Time (t)

  19. Maximum Sustainable Yield Growth / Yield Fishing effort

  20. Simple Abundance Model

  21. Single Species Models • Assessment models are biased because they do not incorporate the predation by other species. • Assessment models are limited because of their emphasis on equilibrium solutions, such as MSY. • Assessment models do not usually account for environmental changes, whether interannual or interdecadal. • A correct assessment approach requires that a multi-species framework be used. • Harvest recommendations from single-species assessment do not consider the needs of other species. • Harvest recommendations from single-species assessment involve the deliberate fishing down of a population and therefore adversely change the ecosystem. • The single-species approach is invalidated, because overfishing has occurred for at least a majority of the world’s fisheries. • Single-species approaches do not account for the indirect effects of fishing (e.g. bottom fishing on habitat quality).

  22. Fishing at MSY level: is it good or bad? 0% 50% 100 50% 100 % PSE AEC MBS ANT ANE ASW PNE PNW ACW PEC IE ANW PCW IW PSW PEC PSW ANT PCW PNW IE ANW ASW MBS ANE ASE AEC PSE IW ACW “BAD” “GOOD” “BAD” “GOOD” A: if fishing at MSY is “good” B: if fishing at MSY is “bad”

  23. Neoclassical Sustainability

  24. Modern Sustainability

  25. Fishery induced changes in world fish composition

  26. Fishing Down the Food Web

  27. Shark Populations NE Atlantic Baum et al. 2003

  28. Fisheries at the crossroad • Fisheries have significantly contributed to human development and can still do so • There are problem areas and avenues for positive change • Change will never be at no cost; but….

  29. The status quo is not an option !

  30. Solutions?

  31. Historical Succession of Coastal Ecosystems • Over-exploitation of large predators • Collapse “Ecosystem Engineering” species • Rise of Microbes Jackson et al. 2001

  32. Historical fishing consequences Jackson et al. 2001

  33. Historical fishing consequences Jackson et al. 2001

  34. Historical fishing consequences Jackson et al. 2001

  35. Jackson et al. 2001

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