Abstract
When we use ocean space for human activities, we should consider sustainability and allowable human impacts.After the 1960's, we have lost 90 percent or more of the tideland of Tokyo-bay by the reclamation. "Uminokouen" is one of the artificial seashore parks developed in 1988 at the southeast of Yokohama and is well known as a relaxation place for the citizens. Over 20,000 people visit there for seashell-digging (SHIO-HIGARI) in a holiday in the spring.It is easy to understand that the human impact is quite large to an ecosystem of living bivalves in the park. Actually,the most part of living bivalves which are grew up after the last summer or autumn disappeared during the season. In this paper, we propose a computational model which predicts the human action of seashell-digging at this park using a multi-agent-algorithm. Comparing the simulation result with the actual data, the staying time of the visitors agrees well. Then, we investigate the relation among the initial spatial distributions of the bivalves, the spatial distributions of the amount of the caught short-neck clam and the trace of the visitors. Then we predict the human impact in the best weekend for the seashell-digging and examine the sustainability of the relaxation park.
