Estuaries and Coasts

, Volume 35, Issue 3, pp 821–838 | Cite as

Food Web Structure and Trophic Control in Central Puget Sound

  • Chris J. Harvey
  • Gregory D. Williams
  • Phillip S. Levin


We developed a food web model of central Puget Sound to provide science-based support for ecosystem-based management and to refine our understanding of bottom-up and top-down trophic forcing. Phytoplankton accounted for a large fraction of total biomass, total throughput, and caused considerable bottom-up effects in most functional groups in a dynamic simulation fit to time series data from 1981 to 2000. Top-down control was most apparent in the case of bald eagles (Haliaeetus leucocephalus), which exhibited keystone tendencies and appeared capable of causing trophic cascades. Increasing top-down control in several predator–prey relationships improved model fits to time series data from 1981 to 2000, but not as much as introducing non-equilibrium dynamics (biomass accumulation terms) to several key vertebrates. Fishing had little effect on system dynamics. Our model appears well-suited for addressing strategic, scenario-based questions of how the community as a whole will respond to management actions.


Puget Sound Ecosystem modeling Food webs Trophic structure Ecosystem-based management Ecopath with Ecosim 



We thank all who contributed to the NOAA technical memorandum (Harvey et al. 2010), upon which this work is based. Support, cooperation, and unpublished data were generously provided by scientists from the Washington Department of Fish and Wildlife (G. Bargmann, D. Bacon, G. Blatz, S. Burton, O. Eveningsong, J. Evenson, K. Henderson, L. Hoines, S. Jeffries, E. Kraig, M. Lance, G. Lippert, M. O’Toole, W. Palsson, S. Pearson, B. Sizemore, K. Stick, D. Stinson, and J. Watson), King County (S. Mickelson), the Puyallup Tribe of Indians (A. Berger), the Washington Department of Ecology (M. Dutch), the Northwest Indian Fisheries Commission (B. Patton), and the NOAA Northwest Fisheries Science Center (A. Albaugh, K. Bartz, A. Guerry, T. Good, and C. Rice). J. Davies created Fig. 1. E. Quimby and B. Tarrant assisted with table creation. I. Valiela, J. Samhouri, I. Kaplan, C. Ainsworth, and four anonymous reviewers provided valuable comments on earlier versions of this paper. This research was supported by funds from the U.S. Environmental Protection Agency.

Supplementary material

12237_2012_9483_MOESM1_ESM.pdf (71 kb)
Table A1 (PDF 70 kb)
12237_2012_9483_MOESM2_ESM.pdf (219 kb)
Table A2 (PDF 218 kb)
12237_2012_9483_MOESM3_ESM.pdf (30 kb)
Table A3 (PDF 30 kb)
12237_2012_9483_MOESM4_ESM.pdf (35 kb)
Table A4 (PDF 34 kb)
12237_2012_9483_MOESM5_ESM.pdf (36 kb)
Fig. A1 Annual landings of functional groups in the PSCB domain, for which time series data were available for most of the 1981–2000 time period. In the three cases where there were “no data” for extended time periods (spiny dogfish, Pacific cod, and small-mouthed flatfish), we assumed landings equal to the mean of all available data between 1981 and 2000. (PDF 35 kb)


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Copyright information

© Coastal and Estuarine Research Federation (outside the USA) 2012

Authors and Affiliations

  • Chris J. Harvey
    • 1
  • Gregory D. Williams
    • 1
  • Phillip S. Levin
    • 1
  1. 1.Northwest Fisheries Science CenterNOAA FisheriesSeattleUSA

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