Basic elements of the biological structure of Pacific Salmon of the genus Oncorhynchus (Salmonifomes, Salmonidae) of Magadan region in the early of XXI century

Gorokhov, M.N.; Volobuev, V.V.; Yamborko, A.V.; Smirnov, A.A.

Basic elements of the biological structure of Pacific Salmon of the genus Oncorhynchus (Salmonifomes, Salmonidae) of Magadan region in the early of XXI century

2020

Gorokhov, M.N. | Volobuev, V.V. | Yamborko, A.V. | Smirnov, A.A.

Information on age, size-weight structure, fecundity and sex ratio of four species of Pacific Salmon reproduced in Magadan region is presented. Changes in the structure of biological indicators for the first two decades (2001–2019) of the 21st century in the main populationsof pink salmon, chum salmon, coho salmon and sockeye salmon are shown. The presence of wedge variability of dimensional-weight characteristics in pink salmon and coho salmon in latitude direction has been established. The pink salmon of an odd row of generations is characterized by a larger size-weight indicators. There has been an increase in average age in chum salmon populations compared to the early 2000s. A perennial prevalence of individuals with two freshwater years of life has been established in coho salmon populations. During anadromous migration, the size-weight indices of coho salmon decrease. Sockeye salmon is represented by limnophilic and rheophilic forms. Resident dwarf males and females are noted in limnophilic nerka populations.

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