A fresh perspective on carp feeding behavior in an aquaculture pond and its consequences for individual growth

The common carp (Cyprinus carpio) is an important species in global aquaculture. To optimize its production, it is necessary to understand its behaviour in relation to environmental and management factors. This study investigated the spatial and temporal dynamics of carp behaviour in a semi-intensive aquaculture pond under controlled feeding regimes over two growing seasons (2022-2023). Using telemetry and stable isotope analysis, we investigated activity, depth utilisation and feeding behaviour in relation to growth and aquaculture practices. The activity of carp and their spatial use changed over time, influenced by temperature, food availability and stocking density. Activity peaked in spring and early summer and was highest at night and twilight. In the warmer months, shallow areas (<0.5 m) were favoured, probably due to thermoregulation, oxygen levels or access to prey. Individual variability in foraging site use and food composition correlated with growth, highlighting the importance of behavioural traits in resource acquisition. A flood-induced rise in stocking density in 2022 increased competition for food, resulting in higher activity and lower growth compared to 2023. Stable isotope analysis showed that benthic invertebrates were the main food source, supplemented by cereals, emphasising the importance of a balanced natural and artificial diet. Our results emphasise the value of telemetry and isotope analysis for improving aquaculture practises. Recommendations include adapting feeding to seasonal and individual behaviour, mitigating density effects and promoting sustainable practises to optimise carp production.