Common carp is the most extensively farmed fish globally, with traditional pond culture systems in central and eastern Europe raising significant welfare questions around winter starvation, oxygen depletion and slaughter methods.
Carp welfare in traditional pond culture involves seasonal cycles that create recurring welfare challenges. Autumn pond drainage involves crowding fish at extremely high densities as water levels drop — a severe acute welfare event. Winter holding at low temperatures in oxygen-depleted ponds is associated with high mortality and chronic welfare compromise. Live transport in oxygen-aerated tanks is better than transport without water but still causes handling stress. The practice of selling live carp at Christmas markets — where fish may be held in buckets and killed by consumers — represents one of the most significant welfare failures in European food retail. Humane slaughter education and pre-slaughter stunning are improving in commercial contexts but retail live sales remain unregulated in some countries.