Gametogenesis of Pacific Salmons: 1. The State of Gonads of Juvenile Pink Salmon Oncorhynhus gorbuscha under the Conditions of Its Natural and Hatchery Reproduction in Sakhalin Oblast

Abstract

The state of gonads of natural juvenile pink salmon Oncorhynhus gorbuscha, which was caught in five rivers during its downstream migration from spawning grounds, and hatchery juvenile pink salmon with different rearing periods, which was taken from 22 fish hatcheries in Sakhalin oblast, have been studied. The germ cells in the testes of all studied fish were represented by a few gonia. A single generation of oocytes of the previtellogenic period had already been formed in the ovaries of all females; the germ cells of earlier development stages (gonia and meiocytes) were hardly present.