Abstract
The matter flow from terrestrial plants and aquatic algae to juvenile masu salmon was estimated in the Gokibiru River, Hokkaido, Japan. The stomach contents of masu salmon, stable isotope rate of invertebrates and plants, and assimilatory rate between masu salmon and invertebrates were analyzed. The weight composition of masu salmon stomach contents was converted into assimilation composition following a rearing experiment. The contribution of terrestrial plant matter in invertebrate diets was estimated by stable isotope analysis. The total contribution of terrestrial plant matterial to diets of juvenile masu salmon was 42.2-78.1%. The main mediators between juvenile masu salmon and terrestrial plants were aquatic invertebrates (e.g., Gammaridea and Heptageniidae) in summer, autumn and winter, and terrestrial insects (e.g., Lepidoptera larva) in spring.
