In August 2000, the hydrogen isotope dilution method was used on 7 adult male Atlantic walruses (Odobenus rosmarus rosmarus) (weight: 1197±148 kg, mean±SD, range 1013-1508 kg) at a terrestrial haul-out in Northeastern Greenland to determine their body water pool sizes and body water turnover rates. During immobilization by use of etorphine HCl (reversed with diprenorphine HCl), a first blood sample was taken to measure background isotope levels. The animals were then enriched with deuterium oxide by infusion into the epidural vein. During recovery, while the animals were still on the beach, blood was sampled via an epidural catheter, at regular intervals, for up to seven hours after the initial enrichment to assess isotope equilibration in the body water pools. Five individuals returned to the haul-out after feeding trips of varying duration (158±86 hr, 44-287 hr) where they were immobilized again and sampled for blood. The equilibration time for the isotope was found to be as short as 2 hours, total body water contents ranged between 60 and 64% of the calculated total body mass, and the half-life of body water ranged between 3.03 and 33.39 days. The results indicate that stable isotopes can successfully be used on walruses to estimate water metabolism as well as other metabolic parameters.
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14th Biennial Conference on the Biology of Marine Mammals, 2002