Impact of environmental factors on the growth and maturation of farmed Arctic charr

Abstract

Farming of Arctic charr mainly takes place in land‐based farms applying intensive rearing methods with relatively high production costs. Depending on local conditions at each site, it is possible to regulate important environmental factors to improve productivity and well‐being of the fish. Knowledge about how these different environmental factors affect various farming traits is important to reduce production costs. This review shows how rearing temperature, photoperiod, salinity and feeding rate can affect farming traits such as growth rate, maturation and feed conversion efficiency of Arctic charr. High growth rate during juvenile phase when the fish are reared at higher temperatures can result in higher incidence of maturation during the on‐growing period. Overall, more moderate rearing temperature regimes seem to result in better long‐term growth rates. Photoperiod manipulation and feed ration can be used as tools to improve growth and reduce maturation. It is possible to rear Arctic charr successfully up to market size in salinities up to c. 27–28 ppt. However, extended rearing resulted in higher ratio of sexually mature fish at 29 than at 25 possibly linked to higher rearing temperatures in brackish water. Future studies should focus on better preserving the potential high growth rate of Arctic charr during juvenile phase into the on‐growing period and establish protocols to improve the seawater tolerance of Arctic charr.