Major Trends in Global Fisheries (and some generalizations)

1. Major Trends in Global Fisheries (and some generalizations) Daniel Pauly Sea Around Us Fisheries Centre, University of British Columbia, Vancouver 2005 Forum North American Association of Fisheries Economists Vancouver, B.C. Thusday, May 26, 2005

2. Here is a map of global marine fisheries in 1998. Not very exciting, except for the anomalies (red)…. 0 There are problem with Peru and Chile. But China?

3. The differences between this catch map, and the predictions of a statistical model of the form ‘Catch = f(PP, SST, Depth, etc.)’ are largest in Northeast Asia… ..and this is due to over-reporting by China (Watson & Pauly, Nature, 2001).

4. Correcting for this shows that global fisheries catches have been declining since the late 1980s: (Watson and Pauly, Nature, 2001).

5. In fact, the decline is even stronger if one considers discarded fish (red). This was not mentioned by FAO when the last estimate (dot E; 7-8 million tonnes) was released. Landings + discards Global landings, w/out Peruvian anchovy Peruvian anchovy Zeller and Pauly (in press)

6. Now to the ecological processes underlying overfishing: using diet composition and other biological data, we can readily construct ecosystem models such as this (though usually with more boxes), covering different areas and years…

7. Such models can be generalized, using: • Our ½ degree lat./long grid system; • For example in the North Atlantic, 23 models representing 15 North Atlantic ecosystems to supply information over time and space; • A multiple linear regression stratified over the North Atlantic area.

8. (t/km2) Biomass of table fish in 1900 (Christensen et al. 2003, Fish & Fisheries)

9. and in 2000….

10. Same thing in Northwest Africa, where European fleets operate on the basis of questionable ‘access agreements’. Christensen et al. Dakar Conference Proceedings (2004)

11. 1960 The development of bottom trawling yielded similar results in Southeast Asia… 2000 Note Brunei as exception (because of the oil rigs functioning as MPA) Christensen et al. (2003)

12. 5 4 Trophic Level 3 2 Not only do the biomasses decline, but their composition change… Watson and Pauly In: Atlas of the Ocean

13. The process is ubiquitous… 3.6 3.55 North Atlantic 3.5 3.45 Trophic level 3.4 Global coastal 3.35 3.3 3.25 3.2 2000 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Year Pauly and Watson (Phil. Trans. R. Soc.B, 2005)

14. Here is is one instance, the USA (‘South Atlantic’ and Gulf of Mexico) and the rest of the West Central Atlantic (FAO Area 31). Pauly and Palomares (Bull. Mar. Sci. 2005)

15. Trophic level change " ≤ -0.5 " > -0.5 - -0.3 " > -0.3 - -0.1 " > -0.1 - -0.05 " > -0.05 - < 0 " ≥ 0 And here as a global map of trophic level change (1950-2001) Pauly and Watson (Phil. Trans. R. Soc. B, 2005)

16. One solution often advocated is Marine Protected Areas (MPAs), of which there is now an increasing number along the the world’s coastlines…

17. However, most of these MPAs are tiny, and their growth rate is not sufficient to meet targets... 1% of world ocean area (growth rate ~ 5% year-1) L. Wood (PhD thesis, in prep.)

18. However, we could imagine a situation where it may become too expensive to fish in deep waters, or indeed to operate large industrial fleets... And thus we might get a few MPAs that way… Pauly et al. (Science, 2003)

19. Anyway: I end these slides with this. It shall serve as background to further generalizations