Pilot Study on Fish Species Composition Using Environmental DNA in Marine Sediment

The environmental DNA （ eDNA ） derived from fish in marine sediments is preserved for long periods and could be used as successive proxy data for fish assemblages. However, metabarcoding analysis for fish eDNA has never been applied to marine sediments. In this study, metabarcoding analysis for fish eDNA was applied to the Tohoku Earthquake sediment samples collected from Otsuchi Bay after the tsunami induced by the 2011 Earthquake off the Pacific Coast of Tohoku to track the past fish species composition. We successfully detected 17 fish eDNA from sediment samples throughout the study period. The number of sequence reads of migratory fish species was relatively high in the samples of the first two years, whereas that of demersal fish species increased in the samples of the latter two years. Temporal changes in fish species identified by eDNA metabarcoding are consistent with those in fish species identified by visual censuses in the Pacific coast of northeastern Japan. Thus, eDNA in marine sediments could be used to track the past fish species composition.