Patterns of reproduction for coho salmon Oncorhynchus kisutch in the Khabarovsk Region

Abstract

Reasons for deviations in actual number of sexually mature offspring from the parent-offspring ratio described by Ricker equation are investigated for coho salmon in the Okhotsk district. The deviations are well explained by variability of air temperature and precipitation during the feeding period of juveniles in rivers. Combined influence of the number of parents and weather conditions in the freshwater period of life explains more than 90 % of variability for coho salmon year-class strength. The influence of weather factors is realized possibly through conditions of nutrition and growth of juveniles. The results are discussed in comparison with similar studies of some populations of pink and chum salmon.

Keywords

• pacific salmon
• oncorhynchus kisutch
• okhotsk sea
• year-class
• weather factor