Minimum requirements for modelling bivalve carrying capacity

The concept of carrying capacity of an ecosystem for natural populations is derived from the logistic growth curve in population ecology, and defined as the maximum standing stock that can be supported by a given ecosystem for a given time. This definition needs to be modified for the exploitation of ecosystems. Carrying capacity for exploitation is defined as the standing stock at which the annual production of a marketable cohort is maximized. For bivalve suspension feeders, the dominant factor determining the exploitation carrying capacity at the ecosystem scale is primary production. At a local scale carrying capacity depends on physical constraints such as substrate, shelter and food supply by tidal currents. We evaluate critically some existing models of exploited ecosystems for shellfish cultivation in order to formulate the minimum requirements of a generic carrying capacity model. Generic models can be developed for both the ecosystem scale and the local scale, depending on the aim of the modelling. Transport processes, sediment dynamics and submodels for organism and population level processes are minimum requirements for carrying capacity modelling.