Differences in temperature and oxygen regimes in sockeye salmon nests on spawning-grounds of various kinds [Russian Federation]
1990
Il'ina, L.V.
Temperature and oxygen regime dynamics was investigated in sockeye salmon nests of the spring race on two spawning-grounds different in water supply in the Azabachye Lake (Kamchatka). On the river spawning-grounds, considerable changes in water temperature were observed in winter and spring, as well as a high oxygen content. The spring spawning-ground is characterized by stable temperatures in nests throughout the period of investigation and by low oxygen content in water around the fish roe. Temperature differences are responsible for differences in the time of fry hatching and emerging from the nests. The emergence of young sockeye salmon from the nests on the river spawning-ground happens immediately before its migrating into the lake. On the spring spawning-ground, young sockeye salmon begins active feeding as early as in winter and reaches considerable size to the beginning of migration into the lake. Oxygen differences in sockeye salmon nests on these spawning-grounds may influence on the whole size of sockeye salmon progeny because a short supply of oxygen results in a high death-rate of the roe. The revealed fry differentiation in size before feeding in the lake may promote survival of the progeny at the subsequent stages of life
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