Rainbow trout are farmed extensively in UK freshwater systems. Their welfare needs include clean, well-oxygenated water, appropriate stocking density and humane slaughter methods.
Rainbow trout welfare in UK farms varies significantly between producers. At best-practice farms, water quality is continuously monitored, stocking densities are managed responsibly, and slaughter involves effective stunning. At lower-welfare operations, overcrowding leads to chronic stress, disease pressure is high, and slaughter may cause unnecessary suffering. The RSPCA Assured scheme provides the best available consumer guide to higher-welfare UK trout, though even this certification represents a minimum rather than an ideal standard. The trout farming industry is well-placed to adopt welfare improvements that are already implemented in best-practice Norwegian salmon farming.