Mortality rates in farmed trout are a key welfare indicator. Understanding the causes of mortality and implementing evidence-based management can simultaneously improve welfare and production outcomes.
Mortality rate in farmed trout is both a welfare indicator and a welfare driver: fish that die have experienced a terminal welfare event, and the conditions causing high mortality (disease, overcrowding, poor water quality) are the same conditions causing suffering in fish that survive. Reducing mortality is therefore simultaneously a welfare improvement and a production improvement, creating one of the clearest alignments between welfare and economics in aquaculture. The interventions that reduce mortality, including lower stocking density, better water quality management, skilled handling protocols, and vaccination programmes, all reduce suffering in the fish population as a whole. Consumer choices for welfare-certified trout that require mortality monitoring and maximum thresholds directly incentivise the management improvements that save fish lives and reduce suffering.