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The sea around us project : assessing the impact of fisheries on marine ecosystems and food security Pauly, D. (Daniel); Tavakolie, Ar’ash; Zeller, Dirk, 1961- 2012-11-01

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The Sea Around Us Project: Assessing the impact of Fisheries on Marine Ecosystems and Food Security Daniel Pauly, Ar’ash Tavakolie and Dirk Zeller Sea Around Us Project Fisheries Centre, UBC    Open Access Week @ UBC This graph, illustrating a Canadian tragedy, leads to several questions. One of them is: how typical is the story of the Northern cod fishery? Can we generalize? And it goes on! We can define, for each catch time series … Now let’s apply these definitions to the global FAO catch statistics…  Fully exploited Developing Underdeveloped… Over-exploited Crashed S to c k s  ( % ) The overall picture is easy to interpret… Developing Fully exploited Over-exploited Crashed Underdeveloped Also, it is tempting to project these trends… S to c k s  ( % ) 2048 ? Let’s generalize: ecosystems are ‘pyramids’ of flows: . . . . . . . . . . . *. . . . . . *. *. *. *. *. *. * . . . . . . .  10%  10%  10% *. 4 3 2 1 and each species tends to have its own trophic level… The expansion starts: marine ‘primary production’ required by fisheries in the 1950s… 1950 0% 30% 2005 0% 30% The expansion continues: marine ‘primary production’ required by fisheries in the 2000s Change in the fraction of the ocean under fisheries exploitation, 1950 to present Fisheries have expanded not only offshore, but also deeper and southward 1950 1960 1970 1980 1990 2000 Year 2000 1500 1000 500 0 D e p th  ( m )  0 1 2 3 4 5 6 7  High catch Low catch 3.2 3.3 3.4 3.5 3.6 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Year T ro p h ic  l e v e l Global coastal North Atlantic 2000 Another generalization emerges when we compute the mean trophic level of world catches. This shows a global decline… Pauly et al. (Science, 1998) And this means that ‘fishing down’ is everywhere We can see from space how trawlers stir up sediment… Photo courtesy of Dr. Kyle van Houten (Duke University) Here: shrimp trawlers off the Texas Coast, Gulf of Mexico Dead zones are increasing in number and size. One example of this is in the northern Gulf of Mexico, whose extent broadly overlaps with sources of jellyfish outbreaks The effect of all this is that jellyfish appear to increase almost everywhere... Increase Stable/Variable Decrease To test this, a global analysis was conducted of cases of increases, decreases or no changes on a global basis. The key result is here: Brotz al. (Hydrobiologia, 2012) Meanwhile, thing are heating up… ……….. Al Gore & IPCC: Nobel Prize 2007 Observed climate-induced shifts in distribution ranges Perry et al. (Science, 2005) Cod Angler fish Snake blenny Poleward shifts in distribution ranges of marine species, e.g., in the North Sea. Probability of occurrence by water temperature Simulating poleward shifts using temperature- abundance profiles… Small yellow croaker (Larimichthys polyactis) Relative abundance 0 0 - 0.00015 > 0.0015 - 0.0038 > 0.0038 - 0.0062 > 0.0062 - 0.0095 > 0.0095 - 0.012 > 0.012 - 0.016 > 0.016 - 0.023 > 0.023 - 0.030 > 0.030 - 0.040 > 0.040 Low High Relative abund nce 0.00 0.05 0.10 0.15 0.20 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Temperature (degree C) P ro b a b il it y  o f o c c u rr e n c e Small yellow croaker Year 0 Year 2 Small yellow croaker Year 4 Small yellow croaker Year 6 Small yellow croaker Year 8 Small yellow croaker Year 10 Small yellow croaker Year 12 Small yellow croaker Year 14 Small yellow croaker Year 16 Small yellow croaker Year 18 Small yellow croaker Year 20 Small yellow croaker Year 22 Small yellow croaker Year 24 Small yellow croaker Year 26 Small yellow croaker Year 28 Small yellow croaker Year 30 Small yellow croaker  Projected change in catch potential in 50 years Cheung, Lam, Kearney, Sarmiento, Watson, Zeller and Pauly (Global Change Biology, 2009) Changes in catch potential, by EEZ Cheung, Lam, Kearney, Sarmiento, Watson, Zeller and Pauly (Global Change Biology. 2009)       Kleisner et al. 2012. Using global catch data for inferences on the world’s marine fisheries. Fish and Fisheries. Kleisner et al. 2012. Using global catch data for inferences on the world’s marine fisheries. Fish and Fisheries. Kleisner et al. 2012. Using global catch data for inferences on the world’s marine fisheries. Fish and Fisheries. Acknowledgements… • Thanks to the Pew Environment Group and Lenfest Ocean Program for funding    • Fisheries Centre, University of British Columbia  • Members of the Sea Around Us Project: and many others. visit us at


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