Report- High mortality in aquaculture hatcheries (Dyrevernalliansen)

Unnaturally high juvenile mortality and poor reporting in aquaculture hatcheries are among the main findings of Dyrevernalliansen and the Norwegian Veterinary Institute’s project «Småfiskvel».

The project aimed to correlate mortality rates with operating conditions in hatcheries. The goal was to identify which operating conditions are connected to mortality or poor welfare, and which can be described as success factors. Production form, biosafety, water quality, causes of mortality and welfare were among the topics covered.

The highest mortality rates were found in the smallest weight group, in the juveniles weighing less than three grams. The mortality data from the Norwegian Food Safety Authority also revealed clear differences between the hatcheries, with some consistently reporting high mortality rates over several years. This indicates that production methods and routines, rather than biology, are causing fish deaths.

An unexpected main finding was the less-than-desired quality of the data, highlighting the need for improved reporting and data quality for effective analysis. Apart from higher mortality rates in fish under 3 grams and an increase in total monthly mortality after 2014, no significant differences were found between operational modes and other hatchery conditions due to data limitations.

Dyrevernalliansen will advocate for daily or weekly reporting with quality control to monitor fish throughout production and further research to identify the causes of high mortality.