Influence of spatial heterogeneity of artificial reefs on food sources and trophic levels of marine animals based on stable isotope ratios

•Food sources and trophic levels of marine animals were studied using stable isotopes.•The trophic levels of all species were highest in March and lowest in November.•Within two years following, trophic levels of fish first decreased and then increase.•Zoarces elongates adapted to the reef area faster than other fish. The food sources and trophic levels of four species of fish (Hexagrammos otakii, Pholos fangi, Sebastes schlegelii, Zoarces elongates) and six species of invertebrates (Octopus variabilis, Rapana venosa, Oratosquilla oratoria, Alpheus japonicus, Alpheus distinguendus, Charybdis japonica) prior to and following the formation of spatial heterogeneity of artificial reefs (ARs) were studied using stable isotopes. The trophic levels of fishes were significantly higher than those of invertebrates (P