Abstract
The objective of this study is to elucidate distribution characteristics and population dynamics of the gastropods, Cerithidea cingulata in Katsuura tidalflat of river mouth, Tokushima Prefecture of the Shikoku Island. C. cingulata is one of the endangered species, but dominant one in this muddy tidal flat.
It was quantified sediment characteristic of C. cingulata, focused on physical characteristics of sediments such as particle size and difference in elevation. We conducted population investigation in every month for 6 years. It is found that there are two or three cohorts at least and C. cingulata has grown in summer. It was recognized the most highest population density was 246 individuals/m2. P/B ratio have fluctuated 0.37 ~ 1.26 in each year. P/B ratio of C. cingulata is smaller than other gastropods. It was need to consider carefully analysis function of ecosystem in tidal flats using P/B ratio.
