BIOLOGIYA MORYA, 2018, Vol. 44, No. 1, pp. 36-40

Condition of ovaries in hatchery-reared juvenile summer- and fall-run chum salmon, Oncorhynchus keta (Walbaum, 1792), in Sakhalin Oblast

© 2018 V. S. Kolomytsev¹, A. E. Lapshina², O. V. Zelennikov¹

¹Saint Petersburg University, St. Petersburg 199034;
²Sakhalin Basin Agency for Fishery and Conservation of Aquatic Biological Resources (FGBU Sakhalinrybvod), Yuzhno-Sakhalinsk 693006

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The condition of ovaries in juvenile fall- and summer-run chum salmon prior to release was studied at five fish hatcheries operated on Sakhalin Island. It has been found that juveniles released from different hatcheries, while having a similar body weight, may differ in the degree of development of their ovaries. Juvenile summer-run chum showed a lower oogenesis rate at the hatchery with the warmest water and a higher oogenesis rate at the relatively cold-water hatcheries, compared to that of fall-run juveniles.

Key words: Sakhalin, chum salmon, fish hatchery, oogenesis, oocytes.