Based on materials collected in the fry survey of February–March 2002, an analysis of the microstructure of otoliths of Champsocephalus gunnari with lengths of 5.5–13.3 cm was performed. The studied fish represent a mixture of two generations: spawnings from 1999–2000, and from 2000–2001. The average width of their diurnal growth zone in the first 100 days of life is 6 m at TL 4.5 cm; subsequently, this average width of increments decreases and, at 500 days, is 2.8 m (TL up to 13.1 cm). Based on the number of diurnal increments, the duration of the embryonic period of the first generation of 2001/2002 has been assessed to be four months; TL of fingerlings (at the age of 120–150 days), is 5.5–10.4 cm; TL of yearlings (477–533 days), is 12.5–13.3 cm; and the radius of the first annual ring is 0.7–1.3 mm. Size-age ratios can be used to differentiate successive generations when performing fry surveys.

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