scholarly journals The Development of Salinity Tolerance in the Salmon, Salmo Salar (L.) and Some Related Species

1960 ◽  
Vol 37 (2) ◽  
pp. 425-434
Author(s):  
GWYNETH PARRY
Keyword(s):  
Fresh Water ◽  
Salmo Salar ◽  
Salinity Tolerance ◽  
Related Species ◽  
Sea Water ◽  
Osmotic Regulation ◽  
Salmonid Fishes ◽  
Survival Pattern

1. A study has been made of the survival and osmotic regulation of young salmonid fishes following transfer from fresh water to various dilutions of sea water 2. Survival is in the order: Salmo salar > S. gairdnerii > S. trutta and is generally better the larger the fish. 3. The survival pattern of alevins differs from that of the older stages. 4. Hypo-osmotic regulation is first seen in parr and becomes fully effective in smolts.

Salinity tolerance of Gyrodactylus salaris (Platyhelminthes, Monogenea): laboratory studies

1997 ◽  
Vol 54 (8) ◽  
pp. 1837-1864 ◽  
Author(s):  
A Soleng ◽  
T A Bakke
Keyword(s):  
Population Growth ◽  
Survival Time ◽  
Fresh Water ◽  
Salinity Tolerance ◽  
Sea Water ◽  
Infected Fish ◽  
Laboratory Studies ◽  
Water Dispersal ◽  
Significant Difference ◽  
Parasite Survival

The salinity tolerance of the freshwater monogenean Gyrodactylus salaris, infecting Atlantic salmon (Salmo salar) parr, was studied experimentally. Following direct transfer of infected fish from fresh water to 5.0omicron salinity, parasite population growth increased at the same rate as in fresh water and was positively correlated with temperature (1.4, 6.0, and 12.0°C). In 7.5omicron salinity the populations declined and became extinct after a maximum of 56 days, without any significant difference between 6.0 and 12.0°C. However, some infrapopulations demonstrated short periods of growth. At higher salinities (10.0, 15.0, 20.0, and 33.0omicron) the survival time decreased, and there was a negative correlation between survival time and temperature (1.4, 6.0, and 12.0°C). When transferred directly to sea water (33.0omicron) the parasites became opaque and ceased moving after a few minutes. There was no difference in parasite survival time between direct and gradual transfer from fresh water to 7.5 and 10.0omicron, except for one infrapopulation which demonstrated population growth from day 22 after some fluctuations following gradual transfer to 7.5omicron. The present findings support the hypothesis of brackish water dispersal of G. salaris with infected fish migrating between rivers in fjord systems.

Acclimation of Atlantic salmon (Salmo salar L.) smolts to `cold' sea water following direct transfer from fresh water

Aquaculture ◽  
1998 ◽  
Vol 168 (1-4) ◽  
pp. 351-367 ◽  
Author(s):  
Arne M Arnesen ◽  
Helge K Johnsen ◽  
Atle Mortensen ◽  
Malcolm Jobling
Keyword(s):  
Atlantic Salmon ◽  
Fresh Water ◽  
Salmo Salar ◽  
Sea Water ◽  
Direct Transfer ◽  
Atlantic Salmon Salmo Salar

Effect of Dietary Sodium Chloride on Growth of Atlantic Salmon (Salmo salar)

1975 ◽  
Vol 32 (10) ◽  
pp. 1813-1819 ◽  
Author(s):  
H. M. Shaw ◽  
R. L. Saunders ◽  
H. C. Hall ◽  
E. B. Henderson
Keyword(s):  
Sodium Chloride ◽  
Atlantic Salmon ◽  
Fresh Water ◽  
Salmo Salar ◽  
Sea Water ◽  
Dietary Sodium ◽  
Plasma Sodium ◽  
Food Conversion ◽  
Dietary Salt ◽  
Dietary Sodium Chloride

Growth and food conversion efficiency in Atlantic salmon smolts (Salmo salar) in either fresh water or sea water were not demonstrably affected by varying the level of dietary sodium chloride. Large dietary salt loads were almost completely absorbed from the gastrointestinal tracts offish within 24 h, and plasma sodium and chloride concentrations were positively affected at this time.Irrespective of whether fish were undergoing random, spontaneous activity or an enforced, uniform low level of activity, growth rates and food conversion efficiencies were similar when fish were fed the same ration but different amounts of sodium chloride.A possible explanation is that normal renal function in fresh water provides for large amounts of hypoosmotic urine in which excess sodium chloride may be discharged without great expenditure of energy. However, in sea water, where urine flow is minimal, the main route of excretion for the excess electrolytes is across the gills, a process requiring energy.

Osmotic Regulation in Mosquito Larvae

1950 ◽  
Vol 27 (2) ◽  
pp. 145-157 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
External Medium ◽  
Freezing Point ◽  
Anterior Part ◽  
Osmotic Regulation ◽  
Opposite Process ◽  
Normal Environment ◽  
Different Parts

1. The processes of osmotic regulation in the larvae of Aedes aegypti and of A. detritus have been studied by determination of the freezing-point of samples of fluid collected from different parts of the gut. 2. In A. aegypti, kept in fresh water (its normal environment), the fluid passing down the intestine to the rectum is isotonic with the haemolymph. In the rectum it becomes strongly hypotonic before being eliminated. 3. In A. detritus, kept in sea water (its normal environment), the opposite process is observed, the fluid in the rectum becoming hypertonic to the haemolymph and approximately isotonic with the external medium before being eliminated. 4. In A. detritus, which is able to live in dilute media as well as in sea water, the only two specimens from fresh water available for examination were found to have the rectal fluid hypotonic to the haemolymph. 5. The ability of A. detritus, not possessed by A. aegypti, to produce an hypertonic fluid in the rectum is tentatively associated with a region in the anterior part of the rectum and lined with an epithelium distinctly different from that in the remainder of the rectum. This anterior region has not been found in A. aegypti.

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