Overexploitation of fisheries resources: habitat, artificial reefs and learning.

Summary The central theme of this thesis is the study of two problems raised in modern fisheries, habitat degradation and lack of information, which are among the most important causes of overexploitation of fishery resources. The first two chapters are devoted to the examination of the problem of marine habitat degradation linked in particular to destructive fishing activities. The Gordon-Schaefer model is extended to take into account the negative impact of fishing on habitats. The consequences for management are analyzed and the importance of taking habitats into account in the development of fisheries management programs is highlighted. The model developed is then used to evaluate the economic benefits of artificial reefs, a management tool that is increasingly used by artisanal fisheries managers to respond to habitat degradation. Finally, in the third chapter, the role of information for sustainable fishing is examined when the resource is open access. While in the first two chapters it is assumed that complete information is available for the development of management recommendations, in the last study the decision on the exploitation of fishery resources is made in a context where no information on the resource is available. This decision is made individually by each fisherman operating in the fishery. By developing a multi-agent model, we show the impact of fishermen's learning on the overall dynamics of the fishery system.