The Arctic charr story: development of subarctic freshwater fish farming in Sweden

We present an overview of 27 years of experience of domestication and farming of Arctic charr (Salvelinus alpinus) in Sweden. The domestication process included an evaluation of suitable strains for farming, a breeding programme and the study of the biological and behavioural characteristics of the species. Traits of three different Arctic charr populations differing in ecology and appearance were compared during initial 2-year trials under farming conditions. The best-performing population with respect to the growth rate and the lowest frequency of early sexual maturation was a piscivore form and this became the foundation for a breeding programme intended to select for an Arctic charr strain suitable for farming. After 23 years and 7 generations, our selective breeding has resulted in a fast-growing, late-maturing strain much appreciated by farmers. The biological and behavioural characteristics studied included annual and diel locomotor activity, feeding, social and thermal behaviour. Applying our findings in these areas has greatly improved both profits and conditions for the fish. Other investigations have focused on the application and further evaluation of the results from research in practical farming trials, such as evaluation of growth at different farms with different temperature conditions, optimal time and stocking density for start-feeding and evaluation of different feeding schedules. In Sweden, Arctic charr is mainly farmed in net pens situated in nutritionally depleted and extremely unproductive water reservoirs formed by damming rivers to create electric power. Judicious farming of Arctic charr in such reservoirs can restore their nutritional and productivity state to that which existed before regulation. Site selection criteria for Arctic charr farming in such waters have been developed. The development of intensive farming of Arctic charr in Sweden is discussed together with current limitations and future possibilities.