Placing fisheries in their ecosystem context, an introduction

This contribution, which serves as introduction to a special issue of Ecological Modelling briefly discusses some of the implication for research of the widely heard calls for a transition toward ecosystem-based management of fisheries. Notably, the case is made that the research required for this transition does not need, in order to be useful at all, to explicitly address the full complexity of ecosystems. Indeed, the EU-funded project, which led to the most of the contributions in this thematic issue all contribute useful insights on the structure and functioning of the marine ecosystem they covered, and in many cases, on their fisheries impact on these ecosystems. This could be done under the constraints of available data sets because of the software used by all, Ecopath with Ecosim (EwE), whose mass-balance assumption lead to food web description, and to temporal and spatial simulations that can be robust even in data-sparse environments. Two additional contributions, on the methodology of EwE point to potential pitfalls, and to issues of uncertainty.