Real-time monitoring of cause-specific mortality- and losses in industrial salmon farming

Mortality represents a major challenge in farming of salmon in open sea cages. Production takes place in large cages with up to 200,000 fish and offers no other treatment of individual fish than euthanasia of moribund fish. Improvements need to take place as preventing future problems. The described project was initiated with the objective to develop a standardized system for classification of mortality and losses in aquaculture. The WHO's International Classification of Disease (ICD) has served as a model tool, with adaptation into an animal production system. The system is based on causality with the underlying cause of death as the principal variable to monitor. The system describes the fish-farmer as the primary user, and with additional opportunities for the supply industry, authorities, and research to utilize anonymized data. The classification system is organized with an alphanumeric code in a hierarchical structure with three levels: six main categories, causal subcategories at level 2, and in principle, unlimited underlying causes at level three. The hierarchy allow both registration and retraction of data at each of the three different levels. The proposed code is conceptuated to also allow classification of other losses than mortality, thus being able to monitor the effect of the underlying cause for all areas of losses, including quality downgrading, reduced growth, reduced feed conversions etc. A code covering all areas of losses will enable the fish farmer to monitor the total effect of underlying causes, both in biological and monetary terms. Through systematic monitoring it will be possible to target resources in the direction of losses with the highest impact and the interventions with the highest pay-back. By establishing a unique code, it will further be possible to standardize registrations between area of losses within a company, between companies and regions, and potentially also between countries.