The Century-Long Dynamics of Stocks and Average Body Weight of Pacific Salmon in the Russian Far East through the Prism of Climate Cycles and Trends

The complex pattern of variations in the thermal characteristics of the environment surrounding Pacific salmon, including the linear positive trend and periodic changes for a 80-year cycle, has been elucidated. A positive relationship was found between the dynamics of pink, chum, and sockeye salmon harvest and the general vector of variations in the temperature background. The full cycle periods in the population dynamics of pink, chum, sockeye, coho, and Chinook salmon are expected to also last about 80 years, while the cycles of pink, chum, and sockeye salmon are synchronized with temperature extrema. The dynamics of Chinook salmon catches occur in antiphase to those of pink, chum, and sockeye salmon. The extrema for coho salmon abundance are shifted 20–25 years ahead of the extrema for pink, chum, and sockeye salmon and are approximately 15 years ahead of the extrema for Chinook salmon. It is assumed that the maximum of average catches of the common Pacific salmon species (pink, chum, and sockeye salmon) in the current cycle already passed by the early 2020s.The reduction in average catches of Russian Pacific salmon may last until the 2050s, will be higher than the previous minimum, and will reach the level of average annual catches of approximately 250 000 t. During the 70–100-year warming period, as confirmed by ichthyological studies, Chinook salmon has “lost” up to 60% of the average body weight of individuals, while chum, sockeye, and coho salmon have lost up to 25–30%. The average body weight of pink salmon depends on the abundance of individuals feeding together, especially in years when extra-strong year-classes are formed, rather than on variations in ambient temperature.