Untitled

Abstract

The aim of this study is the development of a method to evaluate a suitable habitat condition of a colony of Acropora tumida which is a kind of stony coral. We improved the HSI model which was often used in a quantitative ecological assessment and suggested the PHSI model which was introduced a probabilistic way of thinking. We can evaluate the optimum habitat condition of coral more precisely than the conventional HSI model by applying the PHSI model to an ecological assessment. We estimated the distribution of a colony of Acropora tumida in 1975 by using the PHSI model in which three physics factors was involved and the estimated distribution well coincided with the observed one. In addition, it was found that the average PHSI value of the object sea area has decreased gradually since 1985. And, the present value was approximately 60% in comparison with that in 1970.