Effect of low sea water temperature on water balance in the Atlantic salmon, (Salmo salar L.)

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 13.9 to 5.7 ml/kg/day, and the absolute amount of water absorbed 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/1 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.

Effects of salinity on the growth and lipid composition of Atlantic salmon (Salmo salar) and turbot (Scophthalmus maximus) cells in culture

“…Interestingly, there was little difference between the two cell types with respect to the cell growth curves. It was expected that salmon cells, that were derived from fry, would grow faster at 300 mOsm kg 1, similar to the OP of Atlantic salmon plasma (Dustan and Knox 1992; Lega et al 1992) than at 450-500 mOsm kg-', but to obtain an almost identical result with TF cells was perhaps surprising. TF cells are routinely cultured in media with an OP of 400 mOsm kg-1, which was based on the plasma OP of turbot (Dr. B. Hill, personal communication).…”

“…It was also noteworthy that there appears to be a difference between the cells in culture and intact fish as plasma OPs of 400 mOsm kg I or over in freshwater-adapted fish transferred to sea water are often associated with greatly increased mortality of the fish (Oguri and Ooshima 1977;Alexis et al 1984;Hegab and Hanke 1982;Finstad et al 1988Finstad et al , 1989aHwang et al 1989). Similarly, a plasma OP of greater than 400 mOsm kg I in Atlantic salmon was indicative of osmoregulatory imbalance contributing to high mortality (Lega et al 1992). With cultured cells, whether from a marine species or the freshwater stage of an anadromous fish, the high salinity media were not associated with particularly high cell deaths.…”

“…Abbreviations: ANOVA, analysis of variance; BHT, butylated hydroxytoluene; BSA, bovine serum albumin; DMA, dimethylacetal; EMEM, Eagle's minimal essential medium; FCS, fetal calf serum; HBSS, Hank's balanced salt solution (without Ca 2 + and Mg2+); HPTLC, high-performance thin-layer chromatography; OP, osmotic pressure; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PI, phosphatidylinositol; PS, phosphatidylserine; PUFA, polyunsaturated fatty acid; SE, steryl esters; SM, sphingomyelin; TAG, triacylglycerol. there tends to be a relationship between plasma OP and environmental salinity with OP of freshwater fish plasma generally being in the range 260-360 mOsm kg (Oguri and Ooshima 1977;SchmidtNielsen 1979;Toneys and Coble 1980;Hegab and Hanke 1982;Woo and Tong 1982;Alexis et al 1984;Al-Amoudi 1987;Bentinck-Smith et al 1987;Finstad et al 1988Finstad et al , 1989aHwang et al 1989) and marine fish plasma OP generally being in the range of 310-490 mOsm kg- (Hirano et al 1978(Hirano et al , 1990Morisawa et al 1979;Schmidt-Nielsen 1979;Wertheimer 1984;Nonnotte and Truchot 1990;Avella et al 1990;Rydevik et al 1990;Arnold-Reed and Balment 1991;Weirich and Tomasso 1991;Lega et al 1992). Euryhaline fish species that are tolerant to changes in external salinity, often inhabiting brackish waters, also display a range of plasma OP usually around 350 mOsm kg I (Oikari 1978;Mavares and Perez 1984;Peterson 1990;Ip et al 1991).…”

“…The OP of fish plasma has also been shown to affected by other stresses such as hypoxia (Peterson 1990), transportation (Nikinmaa et al 1983;Robertson et al 1988;Weirich and Tomasso 1991) and water temperature (Toneys and Coble 1980;Alexis et al 1984;Finstad et al 1988). For instance, in Atlantic salmon, plasma osmolality increased from 320 to 440 mOsm kg I as temperature decreased from 3 to 5.6°C to 2 to 1 °C (Lega et al 1992). The ability of fish to osmoregulate is also affected by photoperiod (Dustan and Knox 1992) and season of the year (Finstad et al 1989b;Arnold-Reed and Balment 1991).…”

Effects of salinity on the fatty acid compositions of total lipid and individual glycerophospholipid classes of Atlantic salmon (Salmo salar) and turbot (Scophthalmus maximus) cells in culture

“…Fish are found in habitats with widely differing salinities and, partly as a consequence, the OP of plasma from different species of fish can vary considerably; 260-360 mOsm kg-' for freshwater fish (Oguri and Ooshima 1977;Schmidt-Nielsen 1979;Toneys and Coble 1980;Hegab and Hanke 1982;Woo and Tong 1982;Alexis et al 1984;AlAmoudi 1987;Bentinck-Smith et al 1987;Finstad et al 1988Finstad et al , 1989Hwang et al 1989) and 310-490 mOsm kg-1 for marine fish (Hirano et al 1978(Hirano et al , 1990Morisawa et al 1979;Schmidt-Nielsen 1979;Wertheimer 1984;Nonnotte and Truchot 1990;Avella et al 1990;Rydevik et al 1990;ArnoldReed and Balment 1991;Weirich and Tomasso 1991;Lega et al 1992). The plasma OP of individuals within a given species is variable (BentinckSmith et al 1987) and can also change significantly depending upon environmental salinity and other stresses such as hypoxia, transportation and water temperature (see Tocher et al 1993).…”