Peculiarities of growth and skeletal system development of prelarvae, larvae, and fingerlings of Dolly Varden Trout Salvelinus malma malma inhabiting the rivers of Western Kamchatka in regard to the temperature regime of the spawning grounds

The order of the bone development and the peculiarities of the transitional forms of the skeletal system (cranium and serial structures, i.e., teeth, gill rakers, fin rays, and pterygiophores, spinal bones, predorsalia, and scales) have been studied for prelarvae, larvae, and fingerlings of anadromous Dolly Varden trout Salvelinus malma malma inhabiting the rivers and streams of Western Kamchatka. The fish fry were reared in laboratory conditions (breeders from Bol’shaya River) and sampled in the field (tributaries of Utkholok and Ozernaya rivers). Comparative analysis was performed. Slow growth and osteogenesis have been registered together with high variability of the growth rate of particular bones in regard to the body size increase. Late scale development (second year of life) was the feature of the young fish sampled in Ukhtolok River. We suggest high ratio of the open egg mass of Dolly Varden Trout in the upper stream of the rocky-bottom spring brooks. The intrusion of prelarvae after hatching in the open egg mass into the pebble layer draining by the flow has been found both for the specimens hatched in the laboratory and in the spawning grounds. These individuals tended to stay in this layer during the whole larval period.