Experimental Analysis of the Effect of Low Water Temperature on Oogenesis in Juvenile Chum Salmon

The condition of the ovaries was studied in female chum salmon exposed to a low water temperature for 2 weeks at different stages of embryonic and larval development. A transfer of embryos and larvae from water with a temperature of 10.0–12.0°C to water with a temperature of 1.3–1.8°C slowed both the somatic growth and the development of the germ cell pool in the experimental fish in all variants. Subsequently, the deficits in body and ovarian weight in the experimental fish were not compensated. However, the gonad weight relatively decreased only in the somatic component, without affecting the germ cell pool within a medium-term period. At 50 days after the end of exposure, the condition of the ovaries in the control and experimental fish did not differ regardless of the initial condition of the gonads in embryos and larvae exposed to a low water temperature.