The osmotic concentration of the blood plasma of plaice (pleuronectes platessa) from three habitats of different salinity

• Published in: Netherlands journal of sea research 1977, Vol.11 (2), p.168-183
• Main Authors: Vlasblom, A.G., Vaas, K.F., Rozing, W.
• Format: Article
• Language: English
• ISSN: 0077-7579
• DOI: 10.1016/0077-7579(77)90004-7

Between August 1971 and December 1973 osmotic concentrations of the blood plasma of plaice from Lake Grevelingen and Lake Veere were compared with those of plaice from the coastal North Sea. During that period the salinity of the sea was always higher than that of the two lakes, of which Lake Veere always had the lowest salinity. Plaice were invariably hyposmotic to the surrounding sea or brackish water. The osmotic concenration usually decreased and never increased with the length of the plaice. The influence of temperature on the total and the electrolyte osmotic concentration is stronger in plaice from the North Sea than in those from both lakes, with the result that seasonal fluctuations in plasma osmotic values are more pronounced in the sea than in the lakes, although temperature in the sea fluctuated less than in both lakes. The interaction between temperature and salinity changes with the length of the plaice. Within the length ranges studied, this interaction is strongest in fish from the North Sea and weakest in those from Lake Veere. Thus it seems that plaice that have lived for a longer time in an unusual environment of abnormal salinity—Lake Veere—show the weakest reaction to changes in environmental factors.