Abstract for: A system dynamics model for marine cage aquaculture

A system dynamics model is built in order to study the sustainability of marine cage aquaculture. Profitability is assumed to be influenced by the availability of dissolved oxygen in the water, which is itself influenced by the farmís effluents. The base run suggests that as long as the farm releases organic matter in the water, the level of dissolved oxygen will tend to decrease thus increasing the fish death rate and therefore jeopardizing the aquaculture venture. Three policy options are tested and their effects on the company sustainability are discussed: - Any improvement in feed floatability is not likely to lead to any major change in the farm sustainability; - The introduction of a delay between two production seasons leads to a modification in the pattern of the total profits of the company which tends to take a more linear shape; - The cancellation of one whole season if the amount of dissolved oxygen appears to be under the threshold level of 5 mg/l leads to cancel one season every two seasons and however gives the best results concerning the long term sustainability of the company.