An ExtendSim platform to simulate the effects of trawling on benthic communities

Abstract

ExtendSim is a user friendly software that allows to build simulation models. This software is being used to build a simulation based on a simple conceptual model which assumes that trawling affects benthic communities and that the intensity of this effect depends on the level of fishing effort the community is subjected to and on the habitat characteristics (i.e. muddy, sandy or gravel habitats). The platform presents four blocks, the first one being the platform presentation. A second block is dedicated to the simulation methodology, where the representation of the community through the relative abundance of traits which are known to be vulnerable/resistent to trawling (substrate position, size, feeding mehod, motilty and other attributes) is explained. A third block shows the epifaunal samples from 18 sites in the Mediterranean which are being used to build the model. Finally, in the simulation block, the user is asked for the model inputs, that is, the present fishing effort of the area of interest, a desired fished effort to reach and the habitat characteristics. The simulation will produce different graphical representation of the community trait's structure under each fishing effort (present and desired). As a future challenge, commercial resource status will be link to the benthic community so as to the platform could be used as a management tool for trawling fisheries in an ecosystem approach framework