The purpose of this study was to investigate the total water turnover rate of fasting subadult hooded seals in order to elucidate to what extent these animals rely in seawater drinking/mariposia at this life stage. Considering mariposia is important for later accurate estimations of food consumption using water turnover rate as a proxy. Five subadult hooded seals were kept fasting for 4 days in a seawater pool. Total body water (39.6 ± 2.5 % of total body mass) decreased by 3.1 ± 0.4 % of initial body water over the experimental period. Turnover rates were 16.7 ± 3.9 (influx) and 24.6 ± 4.6 (efflux) ml · dayˉ¹ · kgˉ¹ with a net water loss of 710 ± 51 ml · day-1. It was estimated that the seals drank approximately 947 ml of seawater per day, which corresponds to 61 % of total daily water influx. Initial body water was relatively low as a result of the high body fat (46.9 ± 3.2 % of initial body mass) shown in the animals. It is concluded that subadult fasting hooded seals drink significant amounts of seawater during fasting. Although mariposia stands out as the major source of free water in fasting hooded seals, the amount of seawater ingested is unlikely to provide a net gain of free water as it is provided by metabolic water. However, it may contribute to excrete the excess of urea produced during early phase I of fasting.
Andersen JM, Wiersma YF, Stenson G, Hammill MO (2009) Movement patterns of hooded seals (Cystophora cristata) in the northwest atlantic ocean during the post-moult and pre-breed seasons. Journal of Northwest Atlantic Fishery Science 42:1-11.
Arnould JP, Green JA, Rawlins DR (2001) Fasting metabolism in antarctic fur seal (Arctocephalus gazella) pups. Comparative Biochemistry and Physiology: Part A Molecular and Integrative Physiology 129:829-841.
Arnould JPY, Boyd IL, Speakman JR (1996) Measuring the body composition of antarctic fur seals (Arctocephalus gazella): validation of hydrogen isotope dilution. Physiological Zoology 69:93-116.
Beauplet G, Guinet C, Arnould JP (2003) Body composition changes, metabolic fuel use, and energy expenditure during extended fasting in subantarctic fur seal (Arctocephalus tropicalis) pups at Amsterdam island. Physiological and Biochemical Zoology. doi:10.1086/367951
Boily P, Lavigne DM (1995) Resting metabolic rates and respiratory quotients of gray seals (Halichoerus grypus) in relation to time of day and duration of food deprivation. Physiological Zoology 68:1181-1193.
Bray GA (1960) A simple efficient liquid scintillator for counting aqueous solutions in a liquid scintillation counter. Analytical Biochemistry. doi:http://dx.doi.org/10.1016/ 0003-2697(60)90025-7
Carlini AR, Marquez ME, Ramdohr S, Bornemann H, Panarello HO, Daneri GA (2001) Postweaning duration and body composition changes in southern elephant seal (Mirounga leonina) pups at King George Island. Physiological and Biochemical Zoology. doi:10.1086/322168
Castellini MA, Costa DP, Huntley AC (1987) Fatty acid metabolism in fasting elephant seal pups. Journal of Comparative Physiology B. doi:10.1007/BF00691828
Costa DP (1982) Energy, nitrogen, and electrolyte flux and sea water drinking in the sea otter Enhydra Lutris. Physiological Zoology. doi:10.2307/30158441
Crocker DE, Houser DS, Webb PM (2012) Impact of body reserves on energy expenditure, water flux, and mating success in breeding male northern elephant seals. Physiological and Biochemical Zoology. doi:10.1086/663634
Cherel Y, Robin J-P, Heitz A, Calgari C, Maho Y (1992) Relationships between lipid availability and protein utilization during prolonged fasting. Journal of Comparative Physiology B. doi:10.1007/bf00260757
Depocas F, Fisher HD, Hart JS (1971) Sea water drinking and water flux in starved and in fed harbor seals, Phoca vitulina. Canadian Journal of Physiology and Pharmacology 49:53-62.
Donohue MJ, Costa DP, Goebel E, Antonelis GA, Baker JD (2002) Milk intake and energy expenditure of free-ranging northern fur seal, Callorhinus ursinus, pups. Physiological and Biochemical Zoology. doi:10.1086/338284
Fetcher ES, Fetcher GW (1942) Experiments on the osmotic regulation of dolphins. Journal of Cellular and Comparative Physiology. doi:10.1002/jcp.1030190112
Folkow L, Mårtensson P-E, Blix A (1996) Annual distribution of hooded seals (Cystophora cristata) in the Greenland and norwegian seas. Polar Biology. doi:10.1007/BF02329206
Folkow LP, Blix AS (1987) Nasal heat and water exchange in gray seals. American Journal of Physiology 253:R883-R889.
Folkow LP, Nordøy ES, Blix AS (2010) Remarkable development of diving performance and migrations of hooded seals (Cystophora cristata) during their first year of life. Polar Biology. doi:10.1007/s00300-009-0718-y
Gentry RL (1981) Seawater drinking in eared seals. Comparative Biochemistry and Physiology 68:81-86.
Hammel HT, Elsner RW, Heller HC, Maggert JA, Bainton CR (1977) Thermoregulatory responses to altering hypothalamic temperature in the harbor seal. American Journal of Physiology-Reg I 232:R18-R26.
Hong SK, Elsner R, Claybaugh JR, Ronald K (1982) Renal functions of the Baikal seal (Pusa sibirica) and ringed seal (Pusa hispida). Physiological Zoology. doi:10.2307/30157892
How OJ, Nordøy ES (2007) Seawater drinking restores water balance in dehydrated harp seals. Journal of Comparative Physiology B. doi:10.1007/s00360-007-0152-9
Hudson JW (1973) Torpidity in mammals. Special Aspects of Thermoregulation 1973:97-165.
Irving L, Fisher KC, McIntosh FC (1935) The water balance of a marine mammal. The seal. Journal of Cellular and Comparative Physiology 6:387-391.
Keys A, Brožek J, Henschel A, Mickelsen O, Taylor HL (1950) The biology of human starvation. Oxford, England.
Kleiber M (1961) The fire of life. An introduction to animal energetics. New York, United States. doi:10.1126/science.134.3495.2033
Kvadsheim PH, Folkow LP (1997) Blubber and flipper heat transfer in harp seals. Acta Physiologica Scandinavica. doi:10.1046/j.1365-201X.1997.00235.x
Lea MA, Bonadonna F, Hindell MA, Guinet C, Goldsworthy SD (2002) Drinking behaviour and water turnover rates of antarctic fur seal pups: implications for the estimation of milk intake by isotopic dilution. Comparative Biochemistry and Physiology: Part A Molecular and Integrative Physiology 132:321-331.
Lester CW, Costa DP (2006) Water conservation in fasting northern elephant seals (Mirounga angustirostris). Journal of Experimental Biology. doi:10.1242/jeb.02503
Lifson N, McClintock R (1966) Theory of use of the turnover rates of body water for measuring energy and material balance. Journal of Theoretical Biology 12:46-74.
Lydersen C, Hammill MO (1993) Activity, milk intake and energy consumption in free-living ringed seal (Phoca hispida) pups. Journal of Comparative Physiology B 163:433-438.
Lydersen C, Kovacs KM (1996) Energetics of lactation in harp seals (Phoca groenlandica) from the Gulf of St. Lawrence, Canada. Journal of Comparative Physiology B 166:295-304.
Lydersen C, Kovacs KM, Hammill MO (1997) Energetics during nursing and early postweaning fasting in hooded seal (Cystophora cristata) pups from the Gulf of St Lawrence, Canada. Journal of Comparative Physiology B 167:81-88.
Markussen NH (1995) Changes in metabolic rate and body composition during starvation and semistarvation in harbour seals. In: Blix AS, Walløe L, Øyvind U (eds) Developments in Marine Biology. Elsevier Science, Tromsø, pp 383-391. doi:http://dx.doi.org/10.1016/S0163-6995(06)80040-5
Markussen NH, Ryg M, Øritsland NA (1992) Metabolic rate and body composition of harbour seals, Phoca vitulina, during starvation and refeeding. Canadian Journal of Zoology. doi:10.1139/z92-034
Matsuura DT, Whittow GC (1974) Evaporative heat loss in the California sea lion and harbor seal. Comparative Biochemistry and Physiology. doi:http://dx.doi.org/10.1016/ 0300-9629(74)90847-0
Mrosovsky N, Sherry D (1980) Animal anorexias. Science. doi:10.1126/science.6928327
Nagy KA, Costa DP (1980) Water flux in animals: analysis of potential errors in the tritiated water method. American Journal of Physiology 238:R454-465.
Nordgarden U, Folkow L, Walløe L, Blix A (2000) On the direction and velocity of blood flow in the extradural intravertebral vein of harp seals (Phoca groenlandica) during simulated diving. Acta Physiologica Scandinavica 168:271-276.
Nordøy ES, Aakvaag A, Larsen TS (1993) Metabolic adaptations to fasting in harp seal pups. Physiological Zoology. doi:10.2307/30163747
Nordøy ES, Blix AS (1985) Energy sources in fasting grey seal pups evaluated with computed tomography. American Journal of Physiology 249:R471-476.
Nordøy ES, Ingebretsen OC, Blix AS (1990) Depressed metabolism and low protein catabolism in fasting grey seal pups. Acta Physiologica Scandinavica 139:361-369.
Nordøy ES, Stijfhoorn DE, Raheim A, Blix AS (1992) Water flux and early signs of entrance into phase III of fasting in grey seal pups. Acta Physiologica Scandinavica. doi:10.1111/j.1748-1716.1992.tb09324.x
Noren DP, Crocker DE, Williams TM, Costa DP (2003) Energy reserve utilization in northern elephant seal (Mirounga angustirostris) pups during the postweaning fast: size does matter. Journal of Comparative Physiology B. doi:10.1007/s00360-003-0353-9
Noren SR, Boness DJ, Iverson SJ, McMillan J, Bowen WD (2008) Body condition at weaning affects the duration of the postweaning fast in gray seal pups (Halichoerus grypus). Physiological and Biochemical Zoology. doi:10.1086/528777
Ortiz CL, Costa D, Le Boeuf BJ (1978) Water and energy flux in elephant seal pups fasting under natural conditions. Physiological Zoology 51:166-178.
Ortiz R, Wade C, Costa D, Ortiz C (2002) Renal effects of fresh water-induced hypo-osmolality in a marine adapted seal. Journal of Comparative Physiology B. doi:10.1007/s00360-002-0254-3
Reilly JJ (1991) Adaptations to prolonged fasting in free-living weaned gray seal pups. American Journal of Physiology 260:R267-272.
Reilly JJ, Fedak MA (1990) Measurement of the body composition of living gray seals by hydrogen isotope dilution. Journal of Applied Physioloy 69:885-891.
Renouf D, Noseworthy E, Scott MC (1990) Daily fresh water consumption by captive harp seals (Phoca groenlandica). Marine Mammal Science. doi:10.1111/j.1748-7692.1990.tb00251.x
Richmond CR, Langham WH, Trujillo TT (1962) Comparative metabolism of tritiated water by mammals. Journal of Cellular and Comparative Physiology. doi:10.1002/jcp.1030590106
Rosen DAS, Trites AW (2002) Changes in metabolism in response to fasting and food restriction in the steller sea lion (Eumetopias jubatus). Comparative Biochemistry and Physiology: Part B Biochemistry and Molecular Biology. doi:10.1016/S1096-4959(02)00048-9
Schmidt-Nielsen K (1964) Desert animals: physiological problems of heat and water. Physiological Zoology 37:338-339.
Schots PC, Bue ME, Nordøy ES (2017) Hooded seal (Cystophora cristata) pups ingest snow and seawater during their post-weaning fast. Journal of Comparative Physiology B. doi:10.1007/s00360-016-1048-3
Sepall O, Mason S (1960) Vapor/liquid partition of tritium in tritiated water. Canadian Journal of Chemistry 38:2024-2025.
Skalstad I, Nordøy ES (2000) Experimental evidence of seawater drinking in juvenile hooded (Cystophora cristata) and harp seals (Phoca groenlandica). Journal of Comparative Physiology B 170:395-401.
Skog EB, Folkow LP (1994) Nasal heat and water exchange is not an effector mechanism for water balance regulation in grey seals. Acta Physiologica Scandinavica. doi:10.1111/j.1748-1716.1994.tb09742.x
Sparling CE, Speakman JR, Fedak MA (2006) Seasonal variation in the metabolic rate and body composition of female grey seals: fat conservation prior to high-cost reproduction in a capital breeder? Journal of Comparative Physiology B. doi:10.1007/s00360-006-0072-0
Storeheier PV, Nordøy ES (2001) Physiological effects of seawater intake in adult harp seals during phase I of fasting. Comparative Biochemistry and Physiology: Part A Molecular and Integrative Physiology 128:307-315.
Tarasoff FJ, Toews D (1972) The osmotic and ionic regulatory capacities of the kidney of the harbor seal, Phoca vitulina. Journal of Comparative Physiology A. doi:10.1007/BF00696628
Verrier D, Groscolas R, Guinet C, Arnould JP (2009) Physiological response to extreme fasting in subantarctic fur seal (Arctocephalus tropicalis) pups: metabolic rates, energy reserve utilization, and water fluxes. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. doi:10.1152/ajpregu.90857.2008
Wolf AV, Prentiss PG, Douglas LG, Swett RJ (1959) Potability of sea water with special reference to the cat. American Journal of Physiology 196:633-641.
Alvira-Iraizoz, F., & Nordøy, E. S. (2019). Evidence of seawater drinking in fasting subadult hooded seals (<em>Cystophora cristata</em>). Journal of Animal Behaviour and Biometeorology, 7(2), 52–59. https://doi.org/10.31893/2318-1265jabb.v7n2p52-59