ISSN:
1432-136X
Keywords:
Key words Tritiated water
;
Mariposia
;
Osmolytes
;
Homeostasis
;
Harp seal
;
AbbreviationsADMR average daily metabolic rate
;
H2Ofood water intake from food
;
H2Oresp water influx via respiration
;
rH2O total water turnover
;
SA specific activity
;
TBW total body water
;
V respiratory minute volume
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract This study was undertaken to measure whether young harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) drink seawater and, if so, to investigate how the excess salt load is handled. Blood and urine samples were collected from hooded seal pups (n=3) and harp seal pups (n=3) after 2 weeks of freshwater exposure, at intervals during 3 weeks of seawater exposure and, finally, after 2 weeks of re-exposure to fresh water. Total water turnover, as measured by injection of tritiated water, was 2200 ml · day−1 and 3300 ml · day−1 in hooded seals and harp seals, respectively. The extent of mariposia was taken as the difference between total water turnover and influx of water through food (free and metabolic water) and respiratory water exchange. Seawater drinking amounted to 14% and 27% of total water turnover (rH2O) for the hooded seals and harp seals, respectively. Further evidence of mariposia was obtained from an increase in the excretion rate of the urine osmolytes Na+, Cl− and Mg2+, during the period of seawater exposure. It is concluded that water influx due to seawater drinking can not be excluded as a source of error when estimating food consumption of free-ranging harp seals and hooded seals, by use of labeled water techniques.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003600000116
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