The experience of joint growing of juvenile pink salmon and chum salmon at a fish farms pond type

Abstract

During the 2019-2020 fish breeding cycle, the development of juvenile pink salmon Oncorhynchus gorbuscha and chum salmon O. keta during their joint cultivation was investigated at the Mineralny and Skalny salmon fish farms. The water temperature at both enterprises during the growing of juvenile pink salmon in general for the whole year turned out to be higher, and when growing juvenile chum salmon, on the contrary, it was lower than, practically, at all other fish hatcheries of the Sakhalin region, specialized for the reproduction of these species. In accordance with the temperature regime by the time of release, the mass of pink salmon juveniles on average 634,6 mg at Mineralny and 425,4 mg at Skalny hatchery was higher, and the mass of juvenile chum salmon - 1007,2 and 820,6 mg, respectively, less than at other enterprises on that date in a normal production cycle. The juveniles of pink salmon were fed 3-4 weeks earlier than juveniles of chum salmon. When the latter was released into the ponds, its mass was 130-150 mg more than the mass of pink salmon located there. However, since the juveniles of pink salmon were already actively feeding by the time of joint rearing, juvenile chum salmon did not have a visible negative effect on its growth rate.