Common carp and related species are the most produced farmed fish globally by volume. Their welfare in extensive and intensive systems varies enormously and is underresearched.
Carp welfare receives far less attention than their numerical dominance would justify. As the most farmed fish by volume globally, welfare improvements in carp production could affect more individual animals than advances in any other aquaculture species. Extensive carp polyculture in traditional village pond systems may offer better behavioral welfare than intensive monoculture, but water quality varies dramatically and disease is common. Harvest methods — including draining ponds and manual collection — cause acute stress. Live transport of carp for sale in markets, where they may be kept in crowded tanks or on wet surfaces for hours before slaughter, is a significant welfare concern in many Asian and Eastern European markets. Scaling up welfare research to match production volumes is urgently needed.