Common carp farmed in traditional European pond systems face welfare challenges around oxygen depletion, harvesting stress, and winter management.
Carp welfare in pond systems is closely tied to water quality management. Oxygen depletion during summer algal blooms or winter ice cover causes severe distress and mass death. Autumn harvesting concentrates fish in rapidly shrinking water volumes, causing crowding stress and physical injury. Live transport and sale of carp for Christmas, a tradition in Central Europe, subjects fish to prolonged periods in inadequate water quality, causing significant welfare costs.