First insight of benthic meiofaunal communities and their associations with bottom sediment grain composition around mass aquaculture of fish in the northwestern Nagashima Island, Yatsushiro Sea, Kyushu

We evaluated preliminarily the spatial difference in meiofaunal community structure at higher taxonomic level and their association with sediment grain composition of the seafloor around several aquaculture nets in Nagashima Island, facing a strait connecting the Yatsushiro Sea. No significant difference in meiofauna community structure was detected between aquaculture sites and their adjacent sites. Statistical analyses revealed that the heterogeneities in sediment particles were the primary factors associated with 14% of the observed spatial changes in the meiofauna community structure: with increases in size and variances of sediment grains, the relative abundance of nematodes, which are usually the most abundant among meiofaunal taxa, decreased. On the other hand, the proportions of benthic copepods increased along the environmental gradients. This suggests that variations in interstitial space between sediment particles contribute to a certain degree to regulate meiofauna composition around the investigated aquaculture nets.