Tool name * EcoPath

Ecopath with Ecosim (EwE) is a free ecological/ecosystem modeling software suite. EwE has three main components: Ecopath - a static, mass-balanced snapshot of the system; Ecosim - a time dynamic simulation module for policy exploration; and Ecospace - a spatial and temporal dynamic module primarily designed for exploring impact and placement of protected areas. The tool aims to:

  • Address ecological questions;
  • Evaluate ecosystem effects of fishing; 
  • Explore management policy options;
  • Analyze impact and placement of marine protected areas;
  • Predict movement and accumulation of contaminants and tracers (Ecotracer);
  • Model effect of environmental changes.
Category All, Fisheries Analysis, Impact Assessment, Spatial Planning
What step(s) in analysis framework 2a, 2b, 2c, 5
What step(s) in Governance framework

In general, an Ecopath model requires input of three of the following four parameters: biomass, production/biomass ratio (or total mortality), consumption/biomass ratio, and ecotrophic efficiency for each of the functional groups in a model. Here, the ecotrophic efficiency expresses the proportion of the production that is used in the system, (i.e. it incorporates all production terms apart from the 'other mortality'). If all four basic parameters are available for a group the program can instead estimate either biomass accumulation or net migration. The parameters 'catches of a group', 'net migration', 'biomass accumulation' and 'proportion of the diet predator group i obtains from prey group j', should always be entered.

Data Quality Required

Modification Required

Not available

Expertise Required

Not available

Spatial and Temporal

Temporal: Varying from a typical season or year, to decades or more. When ecosystems have undergone massive changes, two or more models may be needed representing the ecosystem before, (during), and after the changes. Spatial: Ecospace dynamically allocates biomass across a grid map (sketched with a mouse by the user, and typically defined by 20 x 20 cells), while accounting for:Symmetrical movements from a cell to its four adjacent cells, of rate m, modified by whether a cell is defined as 'preferred habitat' or not (running means over adjacent sets of five cells allows for smooth transitions between habitat types, which are also user-defined);User-defined increased predation risk and reduced feeding rate in non-preferred habitat;A level of fishing effort that is proportional, in each cell, to the overall profitability of fishing in that cell, and whose distribution can also be made sensitive to costs (e.g., of sailing to certain areas).


Not available

License cost issues


Literature: References & Manuals *