Investigation of Competition for Space and Food among Mussels on Artificial Structures

A mathematical model of competition for space and food availability among mussels (Mytilus galloprovincialis) is applied to the mussels settling on the artificial substrates around the mouth of Sumida river in Tokyo Bay. The model consists of a physiological growth submodel based on the dynamic energy budget (DEB) model and a competition submodel for space and food. As a result of numerical simulation, the model can predict well the time histories of the averaged shell length and body weight from 11 September to 20 December in 2002. With growth of mussels, a new layer is produced in the mussel bank at the beginning of November. The mussels that form the inner layers stop food ingestion, so the shell length and body weight of them are smaller than those of mussels in the 1st layer. They continue living by consuming the reserved and gonadal materials. Hence the population number maintains the initial value of 100,000 individuals per square meters, however about half of the mussels are starved in the inner layer and the starved mussels do not contribute to food ingestion and oxygen consumption rates of the mussel aggregation (mussel bank). The oxygen consumption rate of the mussel bank is approximately predicted by the developed model, which has less obscurity on the parameter values of respiration rate than the existing SFG based model.