Stable isotopes as a useful tool for revealing the environmental fate and trophic effect of open-sea-cage fish farm wastes on marine benthic organisms with different feeding guilds

► This study examined the environmental fate of fish farm wastes (FFW) using stable isotope ratios of benthic biota. ► We found that FFW significantly influenced the energy utilization profile of benthic consumers near the fish farm. ► δ15N was enriched in two species of suspension-feeders near the fish farm. ► But δ15N was depleted in both species of benthic grazer and deposit-feeder under the influence of FFW. ► If knowing the in situ trophic structure, we can effectively apply this approach to study the fate of FFW discharge.