European and Japanese eel farming raises welfare questions due to capture of wild juveniles, slaughter practices, and the species' complex biological needs.
Eel slaughter methods are among the least humane in aquaculture. Traditional methods including live gutting, spiking, and smoking without pre-stunning cause what is likely prolonged suffering given eel tolerance for hypoxia and ability to remain alive during processing. The reliance on wild-caught juvenile eels for aquaculture seeding means the industry simultaneously causes welfare harms and contributes to the decline of a critically endangered species. The precautionary principle applied to fish welfare supports transitioning away from eel consumption until both welfare and sustainability can be assured.