Effect of Salinity, Photoperiod, Temperature, and Restricted Food Intake on Growth and Incidence of Sexual Maturation of Labrador Arctic charr (Salvelinus alpinus)
MacPherson, Margaret Jeanette
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Economic viability of Fraser River, Labrador Arctic charr (Salvelinus alpinus) aquaculture in Atlantic Canada may be greatly improved if grow-out could be completed in seawater (30 ppt), while having a low incidence of sexual maturation before harvesting. Growth and survival in seawater was investigated among individually PIT-tagged Arctic charr reared in tanks in the laboratory. Direct transfer from freshwater to brackish water (20 ppt), and then acclimation to 30 ppt was successful. The manipulation of photoperiod, temperature, and food ration can be used as practical applications in aquaculture to arrest maturation; this was investigated in two additional experiments. The most effective photoperiod was LD18:6 for 6 weeks starting December 21, which reduced maturation to 43% compared to 78% in controls. Restricted ration from December 21 through March 15 had no effect on maturation, however, rearing females in 5°C compared to 10°C reduced maturation to 15% compared to >80% in controls.