Introductory course: Ecopath with Ecosim

4 and 5 November 2014, Room P31 at ICM-CSIC

This introductory two day course took participants through the specifics of the theory behind Ecopath with Ecosim and give hands on experience in the creation, parameterization, and evaluation of Ecopath with Ecosim models. Participants learned where to find the input data, and how to calculate the parameters needed from empirical equations, and to balancing and fitting their EwE models.

Ecopath has more than 6,000 registered users in 155 countries. It uses the constraints of balancing energy and production in a food web to solve for unknown values and is useful for describing important interactions and knowledge gaps. Ecosim allows for time dynamic simulations of these fluxes driven by forcing data of either fishing or environmental change.

Although the initial model development is straightforward, added capabilities allow you to address wide-ranging policy questions, from evaluating the relative impact of climate and fisheries and tracing effects of bioaccumulation, to optimisation of the placement of marine protected areas and the evaluation of social and economic consequences of management interactions.

The Ecopath software was designed to enable construction of data-rich ecosystem models that can be used in the implementation of ecosystem-based fishery management, although in data-poor systems it shows the most important knowledge gaps for future research. It incorporates the effects of micro-scale behaviour on macro-scale rates and includes biomass and size dynamics for key groups. This has successfully been undertaken in over a hundred ecosystems and can provide insight into system evolution over time in response to changes in productivity and exploitation.

Students’ time was split between lectures and tutorials, with a focus on hands-on development of simple models from scratch using the Ecopath with Ecosim software.

Teachers: Villy Christensen (UBC, Canada), Marta Coll (IRD, France), and Sheila Heymans (SAMS, UK), with assistance from Jeroen Steenbeek (EII, Spain) and volunteers Samuele Tecchio and Xavier Corrales.


Tuesday 4 November
09:00-10:15 Introduction, Ecopath theory, practical: entering data practical
10:15-10:30 Break
10:30-12:30 Ecopath practical on calculating parameters – data mining
12:30-14:00 Break
14:00-15:15 practical, constructing, balancing models
15:15-15:30 Break
15:30-17:00 practical, constructing, balancing models (continued)
Wednesday 5 November
09:00-10:15 Ecosim theory
10:15-10:30 Break
10:30-12:30 Ecosim practical – lab 2
12:30-14:00 Break
14:00-15:15 Ecospace theory
15:15-15:30 Break
15:30-17:00 Ecospace practical

Recommended reading

  • Ahrens, R. N. M., C. J. Walters, and V. Christensen. 2012. Foraging arena theory. Fish and Fisheries 13:41-59
  • Christensen, V., and Walters, C. 2004. Ecopath with Ecosim: methods, capabilities and limitations. Ecol. Modell. 172(2–4): 109–139. doi:10.1016/j.ecolmodel.2003.09.003
  • Christensen V, Ferdaña Z, Steenbeek J. 2009. Spatial optimization of protected area placement incorporating ecological, social and economical criteria. Ecological Modelling 220:2583-2593
  • Christensen V, Walters CJ, Pauly D, Forrest R 2008. Ecopath with Ecosim version 6. User Guide. Vancouver, Canada: Fisheries Centre, University of British Columbia. 235 p. (Can be downloaded from
  • Plagányi ÉE. 2007. Models for an ecosystem approach to fisheries. FAO Fisheries Technical Paper No. 477. Rome: FAO. 108 p
  • Walters, C.J., Christensen, V., Pauly, D., 1997. Structuring dynamic models of exploited ecosystems from trophic mass-balance assessments. Rev. Fish Biol. Fish. 7, 139–172
  • Walters C, Christensen V. 2007. Adding realism to foraging arena predictions of trophic flow rates in Ecosim ecosystem models: Shared foraging arenas and bout feeding. Ecological Modelling 209:342-350
  • Walters C, Pauly D, Christensen V, Kitchell JF. 2000. Representing Density Dependent Consequences of Life History Strategies in Aquatic Ecosystems: EcoSim II. Ecosystems 3:70-83


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