Introduction
Common carp (Cyprinus carpio) is a key species in European freshwater aquaculture, with a production history exceeding 900 years and a strong socio-economic and cultural relevance, particularly in Central and Eastern Europe (Urbanyi, 2026). In addition to its importance in sustainable, low-input pond farming systems, carp production is increasingly influenced by societal expectations and regulatory developments related to animal welfare. Despite this, welfare assessment and management in carp farming remain less standardized compared to terrestrial livestock systems.
Materials and Methods
Animal welfare challenges occur throughout the entire production cycle, but are particularly pronounced during handling, harvesting, transport, and slaughter. Existing regulatory frameworks, such as Council Regulation (EC) No 1/2005, acknowledge welfare risks during transport; however, they were primarily developed for terrestrial animals and are only partially adapted to fish (Jung-Schroers, 2026). During routine management procedures, carp are exposed to multiple stressors, including crowding, netting, sorting, and temporary air exposure. These can result in physiological stress, injuries to skin, fins and gills, and increased susceptibility to disease.
Results
Live transport represents a critical control point for welfare. Key risk factors include high stocking densities (typically 330–500 kg m-3), fluctuations in water quality (oxygen, temperature, pH), and accumulation of metabolic by-products such as ammonia and carbon dioxide (Kuczy��ski, 2026). Inadequate oxygen supply (<4 mg L-1), rapid temperature changes, and prolonged transport duration are associated with increased mortality and sublethal stress effects. Legal and practical considerations emphasize that fish must be transported in an aquatic environment that ensures species-specific needs, with improper practices potentially constituting animal welfare violations (Kuczy��ski, 2026).
Operational Welfare Indicators (OWIs) have been proposed as practical tools to assess welfare in carp under farm conditions. These include environmental parameters (e.g. oxygen saturation, pH), group-level indicators (mortality rates), and individual-based indicators (injuries, behavioural changes). Among these, oxygen levels, pH, mortality, and injury rates are currently considered the most reliable and feasible indicators for routine application (EFSA, 2008). However, the high environmental tolerance of carp complicates the interpretation of these indicators and may mask suboptimal welfare conditions.
Discussion
Future research and development should focus on the refinement and validation of species-specific welfare indicators, including non-invasive and real-time monitoring approaches. Technological innovations in transport systems (e.g. improved tank design, continuous water quality monitoring) and standardized handling protocols are essential to reduce stress and mortality. Furthermore, adaptation of existing legislation to fish-specific requirements and the development of welfare certification schemes could support improved practices and market acceptance (Heistinger, 2026). Strengthening interdisciplinary collaboration between aquaculture, veterinary science, and animal behaviour research will be crucial to advance welfare-oriented carp production.
Acknowledgment
This work was funded by Hungarian Academy of Sciences (MTA).
References
European Commission (2005): Council Regulation (EC) No 1/2005 on the protection of animals during transport.
European Food Safety Authority (2008): Welfare of farmed fish.
Jung-Schroers, V. (2026): Operational welfare indicators for carp at transport. EURCAW-Aqua webinar on carp welfare during transport.
Heistinger, H. (2026): Animal welfare in carp farming. EURCAW-Aqua webinar on carp welfare during transport.
Kuczy��ski, M. A. (2026): Fish transport – case of Poland. EURCAW-Aqua webinar on carp welfare during transport.
Urb��nyi, B. (2026): A guide to pond aquaculture: Sustainable fish farming technology for the future. 1st Edition, Copenhagen, Eurofish International Organisation.