Mortality rates in aquaculture are both welfare indicators and production metrics, with high mortality reflecting poor conditions that cause suffering before death.
Aquaculture mortality rates are among the most practically useful welfare indicators available — high mortality reflects conditions causing suffering before death, not merely production inefficiency. Fish that die from disease, injury or poor water quality almost certainly suffer in the process. Monitoring mortality rates against industry benchmarks and investigating departures helps identify welfare problems in real time. Welfare certification schemes that require mortality monitoring and investigation of elevated rates create accountability structures for continuous welfare improvement. The economic incentive to reduce mortality aligns with the welfare incentive — creating a rare case where market forces support animal welfare.