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“It moves as you go...” baselines in Limfjorden environmental history

“It moves as you go...” baselines in Limfjorden environmental history DK INCOFISH unit: Poul Holm Bo Poulsen Anne H. Marboe Department of History and Social Theory University of Roskilde INCOFISH, WP2 Workshop Tallin, 3 March 2006 Limfjorden Salinity 5000BP - 1990s.

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“It moves as you go...” baselines in Limfjorden environmental history

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  1. “It moves as you go...” baselines in Limfjorden environmental history DK INCOFISH unit: Poul Holm Bo Poulsen Anne H. Marboe Department of History and Social Theory University of Roskilde INCOFISH, WP2 Workshop Tallin, 3 March 2006

  2. Limfjorden

  3. Salinity 5000BP - 1990s.

  4. Limfjord baselines c. 1980-2006 • Mussel scraping • Suffering from depletion of grounds • Mussel & oyster farming • No other commercial fishery • Some angling Data: gov. Statistics, ongoing sci. surveys

  5. Baselinesc. 1860-1980 • Commercial fishing for • Eel • Plaice • Herring • Cradle of modern Danish fishing • Most important fishing area in DK until c. 1900 • Regime shift c. 1980 • Data: gov. Stats., pioneering mar. Bio. In 19th c.

  6. Lif JacobsenThe Limfjord fishery: Economic and ecological explanations for the collapse of the 1920´s Key events in the Limfjord fishery (1890-1925): 1888 First national Fishery Law Introduction of motor driven boats in the fisheries around 1905. Increasing number of fishermen. Increasing amount of fishing gear. 1923/25 Legislation of motor driven winches for pulling seines onboard. Focus on the main species: Eel, plaice, cod and herring Based on: The Danish Annual Fishing Report 1888-1921 Copy of The Fishing Controls correspondence, etc Reports from The Danish Biological Station etch

  7. Growing fishing effort, 1890-1925 • Due to the increasing number of: • Fulltime fishermen. • Motor driven boats (from 1905) • Amount of fishing gear. (“standing gear”)

  8. Relationship between effort, cost and yield. TC, (total cost) and Effort continually increasing. SMEY, (static maximum economic yield) reached by 1895. TR, (total revenue) become smaller due to a negative development in prices (from 1917) foa, (bio economical equilibrium) reached by 1921. MSY, (maximum sustainable yield): ? The interrelationship between the various objectives. Source: Cunningham m.f.: Fisheries Economics an introduction.p.118.

  9. Baselinesc. 1825-1850s • Period of transition • Commercial fishery • Herring collapse • Eel crisis • Whitefish disappears • Emergence of plaice • Emergence of Aurelia • Invention of Danish seine

  10. Limfjorden

  11. North Sea breach in 1825

  12. Baselinesc. 1600-1825 • Phases of very large herring fisheries • Also commercial fisheries for: • Eel (Anguilla anguilla) • Whitefish, (Coregonus lavaretus) Data: pre-stat. era; but proxy data from historical archives

  13. 400 years of catching herring

  14. Time series of fishing effort • Pound nets

  15. Pound nets 1752-1862

  16. Beach seines

  17. Seines in different areas

  18. Gill nets

  19. Eksport af ål

  20. Bundgarn til helt

  21. Cpue whitefish

  22. Social consequences

  23. Baseline(s) report • ‘Same’ water - very different ecosystems over 4 centuries • Causes of change? Depending on baseline • Regime shifts • Fishing mortality • Climate change • Hydrographic change • Episodic events • Societal changes

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