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.

Effects of short‐term starvation periods on flesh quality in Arctic charr (Salvelinus alpinus)in different seasons

“…This is in accordance with the findings of Johnston (1999) and Rasmussen (2001). The fish were reared under ambient temperature, which was substantially lower in March (around 3°C) than in August (around 11°C) in which the latter is considered being near the optimal temperature for growth for Arctic charr of this size (Imsland et al., 2020; Pétursdóttir & Ey�órsdóttir, 1993; Siikavuopio, Saether, Johnson, Evensen, & Knudsen, 2014). Seasonal variations in growth and feeding are known to occur both for anadromous and for landlocked populations of Arctic charr, with lower growth rates in winter (Arnesen, Jørgensen, & Jobling, 1993; Jobling, 1987; Sæther, Johnson, & Jobling, 1996).…”

“…The starved fish displayed lower mean weight during summer already after two weeks, probably related to higher metabolic turnover and better growth in optimal temperature conditions (Imsland et al., 2020) during the summer period at the fish farm. Arctic charr ability to tolerate starvation during several months in their natural habitat is well documented (Hawley, Rosten, Haugen, Christensen, & Lucas, 2017; Klemetsen, Knudsen, Staldvik, & Amundsen, 2003) as Arctic charr experience large seasonal fluctuations in environmental conditions and food availability (Jørgensen & Johnsen, 2014).…”

“…Arctic charr ( Salvelinus alpinus ) has several features that make it an attractive species for farming in colder climates (Imsland, Gunnarsson, & Thorarensen, 2020). It has a relatively high growth rate at low temperatures (Le François, Lemieux, & Blier, 2002; Gunnarsson et al, 2011; Siikavuopio, Foss, Saether, Gunnarsson, & Imsland, 2013), it can be reared at high densities (Jørgensen, Christiansen, & Jobling, 1993) and the flesh is perceived to be of high quality (Gines, Valdimarsdóttir, Sveinsdóttir, & Thorarensen, 2004; Gunnarsson et al., 2012).…”

Effect of rearing temperature on flesh quality in Arctic charr ( Salvelinus alpinus )

“…Arctic charr ( Salvelinus alpinus ) is a stenothermal cold‐water species (Imsland et al., 2020) that is well suited for farming in colder climates (Jobling et al., 1993). It has a relatively high growth rate at low temperatures (Gunnarsson et al., 2011; Francois et al., 2002; Siikavuopio et al., 2013).…”

“…Although Arctic charr grow well at low temperatures, the optimum temperature for growth of juveniles is between 12 and 18°C (Gunnarsson et al., 2011; Imsland, et al., 2020; Larsson et al., 2005; Siikavuopio et al., 2013). The rearing temperature for Arctic charr aquaculture varies widely depending on local condition (Sæther et al., 2013), and this affects the production time and harvest size of the fish.…”