Abstract
Bivalve is one of the representative animal of tidal flat. The objective of this study is to clarify the effect of food source affecting growth of bivalve (Nuttallia olivacea). Carbon stable istope (SI) , composition of fatty acid (FA) and fatty acid specific stable carbon isotope (FA-SI) . In the result, SI of the bulk sample indicated main food sources roughly. However the composition of FA revealed that EPA and DHA were useful nutrients for bivalve. Furthermore, FA-SI showed terrestrial EPA and DHA are more important food source. Therefore, it was considered FA-SI analysis was useful to clarify food web of various ecosystem.