Variations in epifaunal assemblages among different algal species in the coastal waters of the Noto Peninsula, Japan

Algal beds are biodiversity hotspots in coastal ecosystems, forming complex food webs based on seaweeds. Epifauna serve as important indicators of algal productivity and environmental change, interacting closely with their host seaweeds. This study compared the composition of epifaunal assemblages associated with different seaweed species in the Noto Peninsula, Japan, to elucidate their characteristics. A survey of epifaunal communities on 13 seaweed species around Tsukumo Bay revealed significant differences in abundance and composition among species. Epifaunal abundance was particularly high in Sargassum siliquastrum and S. patens. Differences in assemblage structures were observed among seaweed species and sampling sites, with flow velocity, salinity, and water depth identified as key environmental factors. Fucales seaweeds harbored more diverse epifaunal communities compared to Laminariales species. Variations in epifaunal composition among taxa suggest that interactions with host seaweed species play a crucial role in shaping community structure.