The UK produces approximately 16,000 tonnes of rainbow trout annually, primarily in Scottish and English river and loch-based cage and flow-through systems. Welfare research has identified specific challenges in UK trout farming that differ from Norwegian or continental European production contexts.
UK rainbow trout in river cage systems face seasonal welfare challenges: low dissolved oxygen during summer warm spells causes acute stress, and winter ice formation can damage cages. Crowding during grading events — moving fish between cages for size sorting — causes handling stress, scale loss, and fin damage. The UK's relatively small farm scale compared to Norway allows for closer individual monitoring but also means less capital for welfare infrastructure investment. Infectious diseases including rainbow trout fry syndrome (RTFS) and proliferative kidney disease (PKD) cause significant welfare impacts during climate-driven warm water events. Welfare improvements include shade netting, aeration systems, and reduced frequency of handling events.