= 8 Using Ecosim. Part 1: Ecosim inputs = Ecosim provides a dynamic simulation capability at the ecosystem level, with key initial parameters inherited from the base Ecopath model. This chapter describes the steps taken to set up Ecosim scenarios (The Ecosim menu; Ecosim parameters; Group info; Vulnerabilities); read in Time series data; set up Mediation, Forcing and Egg production functions; and set parameters for Fishing effort dynamics. Before proceeding with Ecosim, we recommend you read the introductory material on Ecosim (see links in Introductory material Ecosim), also found in Chapter 3 of the User Guide). You should also be familiar with the published literature on Ecosim, particularly Walters et al. 1997; Walters et al. 2000; Christensen and Walters 2004).