SIMULATING PHYSIOLOGICAL-RESPONSES OF COCKLES (CERASTODERMA-EDULE) TOVARIABLE CONDITIONS WITHIN ESTUARINE MEDIA

A physiological model has been developed to provide a simulation of sc ope for growth responses of cockles Cerastoderma edule to environmenta l factors such as temperature and seston parameters. As in previous tr eatments, model structure consisted of a series of equations represent ing the various physiological processes which are integrated in the en ergy balance of filter-feeders. Unlike these treatments, however, the present model was designed to give account of the separate processing of phytoplankton and detritus, as components of suspended food that ar e submitted to differential selection and absorption. In this way, eff ect of quality indexes based on phytoplankton abundance on growth rate s could be explored. Subsequently, we have applied this model to: (a) simulating scope for growth under conditions subjected to variation in the estuarine media, and (b) predicting growth variability as a funct ion of food regime, by comparing two particular estuaries with contras ting seston characteristics.