Integrating high-resolution telemetry and stable isotope analysis to link behavior, diet, and growth in pond-reared carp

The common carp (Cyprinus carpio) is an important species in freshwater aquaculture and optimizing its production in pond systems requires a detailed understanding of behavior in response to environmental and management factors. In this study, we combined high-resolution acoustic telemetry, stable isotope analysis, and direct sampling of natural food availability to investigate carp activity, space use, diet composition, and growth over two growing seasons (2022–2023) in a semi-intensive aquaculture pond. Telemetry provided fine-scale spatiotemporal data on fish movement and habitat use, while isotope analysis revealed integrated dietary contributions of natural and supplementary food sources. Natural prey sampling enabled us to link observed behavior with resource dynamics. Carp activity peaked in spring and during twilight or nighttime, and shallow areas (<0.5 m) were used preferentially in summer. Feeding ground use declined over days following feeding events and varied markedly among individuals, influencing supplementary food intake and growth. In 2022, a flood brought in ∼13,900 small carp, increasing fish density, intensifying competition, reducing prey availability, and ultimately lowering growth compared to 2023. Our findings highlight the value of combining behavioral, dietary, and environmental monitoring in pond aquaculture systems. This approach enabled us to uncover mechanisms behind individual variation in performance and to formulate practical recommendations for management. These include aligning feeding schedules with diel activity, using multiple feeding sites to mitigate competition, and adjusting feed inputs based on natural food availability, all of which can enhance production efficiency and sustainability.