Effect of low sea water temperature on water balance in the Atlantic salmon

Yu.V. Lega, A.G. Chernitsky, N.M. Belkovsky
Laboratory of Salmonid Biology, Institute of Marine Biology, Dalnie Zelentsy, Murmansk region, 184631, Russia

Accepted: February 11, 1992

Keywords: Atlantic salmon, low temperature, water balance

Abstract

The water balance in Atlantic salmon (Salmo salar L.) overwintering in sea water (34 ‰) was investigated. With a decrease of temperature from 5.6 to 1.0°C the drinking rate decreased from 8.9 to 5.0 ml/kg/day. A decrease in temperature led, however, to an increase in the proportion of water absorbed in the intestines from 60 to 96 %. Blood serum osmolarity increased from 320 to 440 mosm/l with decreasing temperature and there was a reduction in tissue water content from 75 to 69 %. The disturbance of water balance at low temperature may be one of the factors responsible for mortality of salmon overwintering in sea water.

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Yu.V. Lega, A.G.Chernitsky, and N.M. Belkovsky. Effect of low sea water temperature on water balance in the Atlantic salmon, (Salmo salar L.), 1992