Hypoosmoregulation of larvae of the turbot, Scophthalamus maximus: drinking and gut function in relation to environmental salinity
Measurement of blood osmolarity of pre-metamorphic turbot larvae demonstrated that hypoosmoregulation is well established in larvae 6 days post-hatch (121 degree-days) and older. Blood osmolarity of 121-420 degree-day larvae reared in 100% seawater was significantly greater than blood osmolarity of...
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Published in | Fish physiology and biochemistry Vol. 10; no. 6; p. 475 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Netherlands
01.04.1993
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Online Access | Get more information |
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Summary: | Measurement of blood osmolarity of pre-metamorphic turbot larvae demonstrated that hypoosmoregulation is well established in larvae 6 days post-hatch (121 degree-days) and older. Blood osmolarity of 121-420 degree-day larvae reared in 100% seawater was significantly greater than blood osmolarity of larvae reared in 50% seawater. Hypoosmoregulation involved drinking, but instantaneous drinking rates of 340 degree-day larvae reared in 100% seawater were only slightly more than those of similarly aged larvae reared in 50% seawater. Adaptation to environmental salinity involved changes in gut water absorption; 65-74% water absorption occurred in larvae reared in seawater compared to 30-35% water absorption in larvae reared in 50% seawater. Gastrointestinal water absorption occurred prior to the rectum. In seawater this occurred alongside a decrease in gut fluid osmolarity but desalting was apparently less significant than in adult fish. Absolute water absorption by the gut of 340 degree-day larvae reared in seawater was about 2-fold that of larvae held in 50% seawater, while the osmotic gradient between internal body fluids and environmental media differed by 4-fold, which implies changes the in water permeability of skin and/or developing gills. |
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ISSN: | 0920-1742 |
DOI: | 10.1007/bf00004602 |