2003 年 67 巻 2 号 p. 99-110
The Law to Ensure Sustainable Aquaculture Production that was established in the year 1999 determined an environmental criterion based on the relationship between benthic oxygen uptake rate (BOU) and organic matter loading rate. In this criterion, the maximum value of BOU against the organic matter loading is regarded as an indicator of the phase of the maximum biological mineralization process, and the acid volatile sulfide content of the sediment (AVS-S) corresponding to the BOU maximum is defined as the standard value. To examine the method for determining the standard value, we have developed a three-dimensional numerical model, which takes advection, dispersion, deposition and decomposition of organic matter from mariculture system into account. Numerical simulations by the model revealed that it was quite difficult to estimate the BOU maximum through in situ investigations, because it was greatly influenced by the water exchange and oxygen supply. We suggest that the numerical model should be used instead of in situ investigation to determine the standard value. We also applied this model to evaluate the assimilative capacity of existing fish farms in a basin.
