LENGTH-WEIGHT STRUCTURES AND FECUNDITY OF ANADROMOUS MASU SALMON (ONCORHYNCHUS MASOU) FROM WESTERN KAMCHATKA

Masu salmon Oncorhynchus masou is the most thermophilic species among the Pacific salmon, and Kamchat-ka peninsula is the northern border of its distribution. Due to small abundance, the biology of this species on the peninsula is poorly studied. Regular scientific researches of Masu salmon in Kamchatka have been con-ducted since 2009. The length-weight structures and fecundity of mature Masu salmon have been analyzed in several streams on western Kamchatka over a 10-year period (from 2009 to 2018) and present time. It has been established that the length, weight and fecundity of mature fish are different in the rivers of the peninsula. A tendency of increasing the biological characteristic of the species in recent years has been noted.

Investigation of the spawning sockeye salmon in the pool of the Nachikinskoe Lake (South-Western Kamchatka) with the help of a quadcopter in 2018

The Nachikinskoe Lake and its tributaries were first examined in detail with the help of a quadrocopter during running and spawning of early and late sockeye salmon. Quantitative estimates of adult salmon filling in different areas of lake tributaries and its coasts were obtained. The number of spring sockeye salmon was estimated at ~30 thous. specs, and late — at ~145 thous. specs (summation of adults counted every ~2 weeks) and 140 thous. specs (127–153 thous. specs), by means of imitation model. According to the photos from the quadrocopter, the boundaries of the spawning grounds of the late sockeye salmon in 2018 are marked on the space picture. The area of spawning grounds is calculated — 307 thous. m2. The maximum density of distribution of adult salmon exceeded 0.64 specs/m2, the density of spawning was 4.5 specs/m2.