The Condition of Ovaries in Hatchery-Reared Juvenile Summer- and Fall-Run Chum Salmon, Oncorhynchus keta (Walbaum, 1792), in Sakhalin Oblast

Abstract

The condition of the ovaries in juvenile fall- and summer-run chum salmon prior to release was studied at five fish hatcheries that operate 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 salmon 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.