Diversity of life strategies and population structure of Kamchatka mykiss Parasalmo mykiss in the ecosystems of small salmon rivers of various types

The diversity of life strategies and population structure of Kamchatka mykiss Parasalmo mykiss in the ecosystems of small salmon rivers of various types are considered. Hydrogeomorphological differences of the model rivers Kol and Kekhta are found. The preferred habitats are investigated, and their area is determined. It is shown that, in the Kol River, the mykiss having a resident life strategy predominated, and in the Kekhta River—the mykiss with migratory strategy. The key parameter controlling the prevalence of life strategies in each river is the ratio of the area of spawning grounds to the area of feeding grounds and their productivity. The hypothesis is confirmed that, in complex river systems, due to the diversity of biotopes and a higher productivity, the food resources are sufficient for maturation of mykiss and for realization of the resident life strategy (without migration to the sea for feeding). In small rivers of the channel type with their insufficient food resources, the specimens having a migratory life strategy prevail.