Responses of Mytilus edulis L. to varying food concentrations: testing EMMY, an ecophysiological model

In this paper a complex ecophysiological model is presented, which aims to simulate individual growth and reproduction of Mytilus edulis L. The model includes feedback mechanisms in the acquisition and metabolism of natural food sources and partitioning of carbon and nitrogen to the internal state variables: somatic tissue, storage, organic shell matrix, blood and gametes before and after spawning. The model was calibrated with statistical distributions for 38 parameters. The resulting a posteriori parameter sets were applied in a validation procedure. First inputs of one system were used to produce model outcomes with uncertainty bands in order to compare these with system observations not used for calibration. In a second validation step, the model was run with inputs of two different ecosystems. The results of this step were promising, but no acceptable growth could be predicted for the system with low seston and food concentrations.