Patterns and some mechanisms of downstream migration of juvenile salmonids (with reference to the Utkholok and Kalkaveyem rivers in northwestern Kamchatka)

摘要: Principal patterns of the downstream migration juvenile salmonids (Salmonidae) were discovered on basis data three years observations. It was found that time beginning, duration, and scope in each particular year are determined by a complex environmental factors. The crucial abiotic factors temperature, water level river, illumination. biotic comprise trophic factor. play leading role realization at early ontogenetic stages. increases late demonstrated juveniles perform migrations heterogeneous group consisting fish different species specimens stages, various sizes ages, those ready for transition to marine environment variable degrees. analysis allowed us describe some mechanisms control this process.