Habitat-specific variation in stable C and N isotope ratios of pond smelt (Hypomesus nipponensis)

Abstract The aim of this study was to investigate differences in δ13C and δ15N of pond smelt (Hypomesus nipponensis) collected from three brackish lagoons, which have different characteristics, the principal one being the presence or absence of a weir located near the mouth of the outlet channel. The presence or absence of a weir is reflected in a difference in salinity among the study lakes. We found a general pattern of lower pond smelt δ13C values in Lake Mae with lower salinity and higher pond smelt δ13C values in Lake Hwajinpo and Lake Youngrang (lagoons with higher salinity). Pond smelt δ13C values showed little variation among the three lagoons related to pond smelt length, but likely reflected the availability of freshwater prey in Lake Mae. Among the lagoons, we found that pond smelt δ15N values were lower in Lake Hwajinpo compared with pond smelt δ15N values in Lake Youngrang and Lake Mae. This pattern likely shows a difference in anthropogenic nitrogen (N) loading among the lagoons. The results...