Abstract
In recent years, Batillaria multiformis that is an endangered species was identified at the Omaehama in inner part of Osaka Bay. This purpose of research is to reveal the ecology and habitat of B. multiformis in sediment. We researched population density of B. multiformis and characteristics of sediment at Omaehama and 11 tidal flats in the Seto Inland Sea. The population density was 56-1307 ind./m2 at 11 investigaton tidal flats. Silt/clay and water content influenced habitat with/without of B. multiformis by decision tree. Furthermore, it was suggested that the algae biomass contributed to the shell length. Recruitment of B. multiformis in Omaehama in recent years is thought that several tidal flats in Osaka Bay is the source by the network functions and the existence of habitat.
