Bio-economic effects of water shortages on shellfish farming. An integrated dynamic modelling approach

The land-sea interfaces are geographical areas rich in ecosystemic services. However, the increase of anthropogenic pressures is frequently the factor explaining environmental damages phenomena and generating many use conflicts. The integrated coastal zones management has been acknowledged by the different environment international conferences as a sustainability framework. Integration is the key concept on which must be based the reformulation of scientific knowledge required for supporting sustainable governance. That directly questions on the pertinent methods and tools to build for contributing to those decision making processes. This paper explores these topics by focusing on the example of the fresh water share in the Charente river catchment in France. More concretely, we will focus on the consequences of the fresh water availability for the shellfish farming sector during the summer period. Fresh water represents the main means of nutrients transportation and a salinity regulator of the estuarine water masses. Both mechanisms can have effects on the recruitment and growth of cultivated animals. Using an integrative platform of dynamic modelling, the objective of this paper is (1) to build a model integrating relationships between the water hydrodynamics at the Charente watershed scale, the bio-economy of the shellfish farming activity, the internal use competition for fresh water and the external forcing of the system; (2) to assess the economic impacts supported by the shellfish farming sector linked to environmental modifications represented by the associated cost (or benefices) related to gaps between economic performances and productive production functions initially targeted and (3) to propose prospective scenarios of sustainable management trajectories supported by simulation procedures. All modelling developments will be assured by the ExtendSim numerical modelling platform