Conditions for reproduction of juvenile salmon fish in Sakhalin fish hatcheries: oxygen, temperature regimes and sanitary state of factory water sources

Abstract

Conditions of salmon reproduction in 2016–2020 are considered for seven Sakhalin fish hatcheries: Lesnoy, Taranaysky, Buyuklovsky, Firsovka, Lazovoy, Lublino, Okhotsky, with evaluation of water temperature, dissolved oxygen content, and qualitative and quantitative parameters of sanitary-indicative and conditionally pathogenic microflora in the water entered the hatcheries at the stages of eggs and larvae incubation and rearing of juveniles. Indirect indicators as morbidity and mortality of fish were used for the conditions assessment, as well. At all examined hatcheries, the water met requirements for water bodies suitable for fisheries by microbiological indicators. The water temperature and dissolved oxygen content provided rather favorable conditions for the salmon reproduction at all stages of the breeding cycle that was proven by normative values of fish mortality and absence of diseases. However, ranges of temperature and oxygen content at certain stages of chum and pink salmon breeding were wider than the optimal ones described in technological documents and scientific literature.

Keywords

• water temperature
• dissolved oxygen content
• bacteriological parameter
• water quality
• artificial reproduction
• salmon hatchery
• sakhalin