Trophic assessment of red seabream (Pagrus major) as a possible bioindicator of human activities in the South Sea of Korea using stable C and N isotopes

Abstract

To assess the impact of sand mining on resource utilization by the red seabream (Pagrus major) and the trophic structure of fish assemblages two years after mining activities, we compared stable isotope ratios (δ¹³C and δ¹⁵N) and isotopic niches between aggregated mining and control sites in April and August 2022. Our results showed no spatial differences in the δ¹³C and δ¹⁵N values of red seabream between the sand mining and control sites, suggesting that the mining did not affect their dietary resources. Furthermore, the considerable overlap among fish consumers suggested that the fish food web in mining areas has trophic functions similar to those in natural habitats after mining activities. Overall, our study enhances our understanding of ecosystem conservation and the ecological-based management of coastal areas.

Keywords: Fish food web; Isotopic niche; Red seabream; Sand mining; Stable isotopes.