Biological characteristics and age estimation by scales and otoliths of masu salmon Oncorhynchus masou (Salmonidae) from the Okhotsk Sea

Age of masu salmon in catches of RV Professor Kaganovsky trawl survey in the Okhotsk Sea in autumn 2024 is estimated by scales and otoliths. The scale samples were collected from 85 specimens of masu salmon with body length from 240 to 456 mm (weight 159–1425 g) and the otoliths were taken from 70 of these specimens. The percentage of fish at age 1.0+ and 2.0+ was 76:24 for the estimations by scales (N = 76) and 66:34 for the estimations by otoliths (N = 68). All examined specimens were at age R.0+; the masu salmon overwintered at sea (age R.1+) were not observed. Images of the scales and otoliths of fish at ages 1.0+ and 2.0+ are provided with explanations. Biological data on the examined specimens are presented with the coordinates of their capture and results of the age estimation. Spatial distribution of masu salmon in the Okhotsk Sea in autumn of 2024 is discussed on the data of joint survey of RV Professor Kaganovsky and RV TINRO.