The trophic fingerprint of marine fisheries

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Biodiversity indicators provide a vital window on the state of the planet, guiding policy development and management1,2. The most widely adopted marine indicator is mean trophic level (MTL) from catches, intended to detect shifts from high-trophic-level predators to low-trophic-level invertebrates and plankton-feeders3,4,5. This indicator underpins reported trends in human impacts, declining when predators collapse (“fishing down marine food webs”)3 and when low-trophic-level fisheries expand (“fishing through marine food webs”)6. The assumption is that catch MTL measures changes in ecosystem MTL and biodiversity2,5. Here we combine model predictions with global assessments of MTL from catches, trawl surveys and fisheries stock assessments7 and find that catch MTL does not reliably predict changes in marine ecosystems. Instead, catch MTL trends often diverge from ecosystem MTL trends obtained from surveys and assessments. In contrast to previous findings of rapid declines in catch MTL3, we observe recent increases in catch, survey and assessment MTL. However, catches from most trophic levels are rising, which can intensify fishery collapses even when MTL trends are stable or increasing. To detect fishing impacts on marine biodiversity, we recommend greater efforts to measure true abundance trends for marine species, especially those most vulnerable to fishing.

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Figure 1: Changes in MTL relative to unfished ecosystem MTL.
Figure 2: Trends in MTL from global marine catches.
Figure 3: Measured MTL.
Figure 4: MTL for each Large Marine Ecosystem.


  1. 1

    Secretariat of the Convention on Biological Diversity. Global Biodiversity Outlook 2 (Secretariat of the Convention on Biological Diversity, 2006)

  2. 2

    Butchart, S. H. M. et al. Global biodiversity: indicators of recent declines. Science 328, 1164–1168 (2010)

  3. 3

    Pauly, D., Christensen, V., Dalsgaard, J., Froese, R. & Torres, F. J. Fishing down marine food webs. Science 279, 860–863 (1998)

  4. 4

    Pauly, D. & Palomares, M.-L. Fishing down marine food web: it is far more pervasive than we thought. Bull. Mar. Sci. 76, 197–211 (2005)

  5. 5

    Pauly, D. & Watson, R. Background and interpretation of the ‘Marine Trophic Index’ as a measure of biodiversity. Phil. Trans. R. Soc. B 360, 415–423 (2005)

  6. 6

    Essington, T. E., Beaudreau, A. H. & Wiedenmann, J. Fishing through marine food webs. Proc. Natl Acad. Sci. USA 103, 3171–3175 (2006)

  7. 7

    Worm, B. et al. Rebuilding global fisheries. Science 325, 578–585 (2009)

  8. 8

    Pikitch, E. K. et al. Ecosystem-based fishery management. Science 305, 346–347 (2004)

  9. 9

    Rochet, M.-J. & Trenkel, V. M. Which community indicators can measure the impact of fishing? A review and proposals. Can. J. Fish. Aquat. Sci. 60, 86–99 (2003)

  10. 10

    Fulton, E. A., Smith, A. D. M. & Punt, A. E. Which ecological indicators can robustly detect effects of fishing? ICES J. Mar. Sci. 62, 540–551 (2005)

  11. 11

    Shin, Y.-J. et al. Using indicators for evaluating, comparing, and communicating the ecological status of exploited marine ecosystems. 2. Setting the scene. ICES J. Mar. Sci. 67, 692–716 (2010)

  12. 12

    Shannon, L. J., Coll, M. & Neira, S. Exploring the dynamics of ecological indicators using food web models fitted to time series of abundance and catch data. Ecol. Indic. 9, 1078–1095 (2009)

  13. 13

    Yang, J. A tentative analysis of the trophic levels of North Sea fish. Mar. Ecol. Prog. Ser. 7, 247–252 (1982)

  14. 14

    Pauly, D., Watson, R. & Alder, J. Global trends in world fisheries: impacts on marine ecosystems and food security. Phil. Trans. R. Soc. B 360, 5–12 (2005)

  15. 15

    de Mutsert, K., Cowan, J. H., Jr, Essington, T. E. & Hilborn, R. Reanalyses of Gulf of Mexico fisheries data: landings can be misleading in assessments of fisheries and fisheries ecosystems. Proc. Natl Acad. Sci. USA 105, 2740–2744 (2008)

  16. 16

    Caddy, J. F. & Garibaldi, L. Apparent changes in the trophic composition of world marine harvests: the perspective from the FAO capture database. Ocean Coast. Manag. 43, 615–655 (2000)

  17. 17

    Caddy, J. F., Csirke, J., Garcia, S. M. & Grainger, R. J. R. How pervasive is “Fishing down marine food webs”? Science 282, 1383a (1998)

  18. 18

    Powers, J. E. & Monk, M. H. Current and future use of indicators for ecosystem based fisheries management. Mar. Policy 34, 723–727 (2010)

  19. 19

    Sethi, S. A., Branch, T. A. & Watson, R. Fishery development patterns are driven by profit but not trophic level. Proc. Natl Acad. Sci. USA 107, 12163–12167 (2010)

  20. 20

    Litzow, M. A. & Urban, D. Fishing through (and up) Alaskan food webs. Can. J. Fish. Aquat. Sci. 66, 201–211 (2009)

  21. 21

    Christensen, V. & Walters, C. J. Ecopath with Ecosim: methods, capabilities and limitations. Ecol. Modell. 172, 109–139 (2004)

  22. 22

    Tacon, A. G. J., Metian, M., Turchini, G. M. & de Silva, S. S. Responsible aquaculture and trophic level implications to global fish supply. Rev. Fish. Sci. 18, 94–105 (2010)

  23. 23

    Tacon, A. G. J. & Metian, M. Fishing for aquaculture: non-food use of small pelagic forage fish—a global perspective. Rev. Fish. Sci. 17, 305–317 (2009)

  24. 24

    Froese, R. & Pauly, D. (eds) FishBase <> Version 03/2010 (2010)

  25. 25

    Chavez, F. P., Ryan, J., Lluch-Cota, S. E. & Ñiquen, C. M. From anchovies to sardines and back: multidecadal change in the Pacific Ocean. Science 299, 217–221 (2003)

  26. 26

    Zeller, D. & Pauly, D. Good news, bad news: global fisheries discards are declining, but so are total catches. Fish Fish. 6, 156–159 (2005)

  27. 27

    Watson, R. & Pauly, D. Systematic distortions in world fisheries catch trends. Nature 414, 534–536 (2001)

  28. 28

    Anderson, P. J. & Piatt, J. F. Community reorganization in the Gulf of Alaska following ocean climate regime shift. Mar. Ecol. Prog. Ser. 189, 117–123 (1999)

  29. 29

    Mantua, N. J., Hare, S. R., Zhang, Y., Wallace, J. M. & Francis, R. C. A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Am. Meteorol. Soc. 78, 1069–1079 (1997)

  30. 30

    Christensen, V. Fishery-induced changes in a marine ecosystem: insight from models of the Gulf of Thailand. J. Fish Biol. 53 (Suppl. A). 128–142 (1998)

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This work arose out of a working group at the National Center for Ecological Analysis and Synthesis (NCEAS), funded by the University of California Santa Barbara, the US National Science Foundation (NSF), and the Moore Foundation. T.A.B. was additionally funded by the School of Aquatic and Fishery Sciences, University of Washington. The RAM Legacy stock assessment database was funded by the Canadian Natural Sciences and Engineering Research Council and the Canadian Foundation for Innovation; the Sea Around Us Project was funded by Pew Charitable Trusts. Additional collaborators and data contributors are acknowledged in the Supplementary Information.

Author information

T.A.B. designed the study, analysed the data, and wrote the paper; R.W. analysed the Sea Around Us Project catch data; E.A.F. designed and ran the ecosystem model analyses; S.J. analysed some trawl survey series; C.R.M. combined trawl survey data into a global time series; G.T.P. provided and calculated trophic level estimates; D.R. collated and analysed stock assessment data; and S.R.T. analysed the FAO and Sea Around Us Project catch data. All authors discussed the results and contributed to the manuscript.

Correspondence to Trevor A. Branch.

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The authors declare no competing financial interests.

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Supplementary Information

This file contains Supplementary Methods, Supplementary acknowledgments and additional references, Supplementary Tables 1-6, and Supplementary Figures 1-18 with legends. (PDF 2086 kb)

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Branch, T., Watson, R., Fulton, E. et al. The trophic fingerprint of marine fisheries. Nature 468, 431–435 (2010) doi:10.1038/nature09528

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