Water Temperature Variations off the Sakhalin Coast from the Data of Instrumental Observations

G. V. Shevchenko and K. V. Kirillov

The data of instrumental observations of water temperature at autonomous bottom stations in the coastal zone of Sakhalin Island (the depth is 3–17 m) mainly along the southeastern coast are analyzed. The cases of sharp (by 15C per day) temperature drop are detected. They are caused by the strengthening of southern and southwestern winds typical of summer and being the offshore winds which favor the lift of cold water to the surface. This phenomenon is observed every year but its intensity varies depending on the frequency of offshore winds. Along the southwestern coast of Sakhalin, where the offshore effect is induced by northern, northeastern, and eastern winds characterized by the low frequency of occurrence, water temperature drops are rarer and shorter (3–5 days) but rather sharp. The occurrence of cold water (its temperature is sometimes negative) in the shallow coastal zone may lead to the mass mortality of juvenile salmon after its downstream migration in spawning rivers, may impede the approaches of humpback salmon and negatively affect its catch.