Morphological and Genetic Heterogeneity of Sockeye Salmon Oncorhynchus nerka (Salmonidae) of Large Lake–River Systems in Eastern and Western Kamchatka

Probing for depth‐gradient diversification in the riverine‐spawning Dolly Varden: Insights from a recently discovered ecomorph assemblage

“…Lake Kurile serves as a breeding‐nursery for the largest Asian stock of anadromous sockeye salmon Oncorhynchus nerka (Walbaum 1792), which inevitably die soon after spawning. Their biomass, annually brought by more than 1.5 million spawners (>4200 tons) to the lake from the ocean (Khrustaleva & Klovach, 2019), enriches the slope and profundal zone gradually decomposing in the cold water throughout the year. Before modern industrial fishing, the average sockeye returns were even 2–4 times higher, whereas the by‐catch of charr has always remained no more than 2% of the fishery (Selifonov, 1988).…”

“…Fish gained access to the lake 4500-5500 years ago after a lava-pyroclastic dam eroded and the surface runoff was formed (Ponomareva et al, 1986(Ponomareva et al, , 2001(Ponomareva et al, , 2004. The climate of the initial settlement period was close to the contemporary one (Dirksen et al, 2013), so most likely the lake was simultaneously populated by all modern fish species and the adaptation of local charr occurred during numerical dominance of Pacific salmonids and sticklebacks (Khrustaleva & Klovach, 2019;Kirillova et al, 2014). Lake Kurile serves as a breeding-nursery for the largest Asian stock of anadromous sockeye salmon Oncorhynchus nerka (Walbaum 1792), which inevitably die soon after spawning.…”