In the number of generations of the Amur River fall chum salmon (Oncorhynchus keta)

We analyzed the relationship of the number of descendants of fall Amur chum salmon with the number of parents and the variability of weather factors in the reproduction area. Chum salmon offspring abundance was shown to be more strongly dependent on weather variability than on parental abundance during the period under consideration. It was possible to identify a relatively weak relationship between the number of generations and the number of parents only after eliminating the calculated influence of weather factors on the dependent variable. Three weather factor variables have been identified that are statistically related to the number of descendants, but the close correlation between them does not allow us to unambiguously identify the most likely explanatory variable. The number of descendants of the autumn Amur chum salmon, as well as other populations and species of Pacific salmon in adjacent reproduction areas, is most closely related to the amount of precipitation falling during the river period of life. The similarity of explanatory variables is probably related to the common conditions of formation of the water regime of spawning rivers, determined by the monsoon character of climate. The variability of precipitation in the breeding areas of the Amur autumn chum salmon explains 80% of the variance in the number of descendants, therefore, their number is formed mainly at the early stages of the life cycle.