A review of animal welfare in farmed fish and impacts on product quality

From the point of view of the link between animal welfare and human welfare, the potential upgrading driving force of domestic aquaculture industry was discussed, tracing from the products quality-enhancement back to the practical feasibility of the industry-upgrading from quantity to quality. This paper focuses on fish aquaculture, explores the space for improving the quality reputation of domestic fish products from the perspective of animal welfare, and systematically reviews relevant literature from the following aspects. Firstly, the 'Five Freedoms' principle and the definition scope of animal welfare were reviewed, and the development process and current situation of fish welfare were discussed by comparison with the research and development process of animal welfare in livestock and poultry industries. Secondly, focusing on the quantitative assessment of fish welfare, the literatures related to the fish welfare evaluation system were reviewed, the evaluation indicators and evaluation methods were summarized from stress mechanisms of physiological response, behavioral response and psychological/pain response. Thirdly, in view of the fish aquaculture industry, the profiles and practice status of fish welfare were analyzed and discussed, with emphasis on aquaculture production, catching and post-harvest handling. Finally, an ignored fish welfare link from catching to death was pointed out, which is the critical transform phase from live animal to food raw material. Also, a package solution of fish welfare at the quality determination period was prospected: ① to maintain the natural properties of fish to the maximum and break through the dilemma of "fresh but not tasty enough"; ② to change the current situation of sales of primary aquatic products and reduce both quantity and quality losses post-harvest by implement post-fishery industrialization; ③ to reduce carbon emissions in the supply chain by substituting freshness-locked products for live fish. In conclusion, the implementation of animal welfare at the critical transform phase is necessary to provide targeted guidance for the practicing of harvest and post-harvest handling/slaughtering, and at the same time enrich cultural value to domestic seafood products through high-quality products induced by improved animal welfare.