Water flux and estimated metabolism of free-ranging gentoo and macaroni penguins at South Georgia

Davis, Randall W.; Kooyman, Gerald L.; Croxall, John P.

doi:10.1007/bf00258284

Cited by 39 publications

(16 citation statements)

References 22 publications

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“…Metabolic rate measurements were available for macaroni penguins for time spent ashore (resting, courtship, at the nest incubating or guarding the chick and during moult) and at sea while foraging during chick rearing (Davis, Kooyman & Croxall 1983; Brown 1984; Brown 1985; Brown 1989; Davis, Croxall & O’Connell 1989).…”

Section: Methodsmentioning

confidence: 99%

Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguins

Boyd¹

2002

Journal of Applied Ecology

104

101

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Summary 1.Estimating food consumption is central to defining the ecological role of marine predators. This study developed an algorithm for synthesizing information about physiology, metabolism, growth, diet, life history and the activity budgets of marine predators to estimate population energy requirements and food consumption. 2. Two species of marine predators (Antarctic fur seal Arctocephalus gazella and macaroni penguin Eudyptes chrsolophus ) that feed on krill in the Southern Ocean were used as examples to test the algorithm. A sensitivity analysis showed that estimates of prey consumed were most sensitive to uncertainty in some demographic variables, particularly the annual survival rate and total offspring production. Uncertainty in the measurement of metabolic rate led to a positive bias in the mean amount of food consumed. Uncertainty in most other variables had little influence on the estimated food consumed. 3. Assuming a diet mainly of krill Euphausia superba , annual food consumption by Antarctic fur seals and macaroni penguins at the island of South Georgia was 3·84 [coefficient of variation (CV) = 0·11] and 8·08 (CV = 0·23) million tonnes, respectively. This was equivalent to a total annual carbon consumption of 0·35 (CV = 0·11) and 0·72 (CV = 0·23) G tonnes year -1 . Carbon expired as CO 2 was 0·26 (CV = 0·06) and 0·65 (CV = 0·19) G tonnes year -1 for fur seals and macaroni penguins, respectively. The per capita food consumption varied depending upon sex and age but, overall, this was 1·7 (CV = 0·22) tonnes year -1 for Antarctic fur seals and 0·45 (CV = 0·22) tonnes year -1 for macaroni penguins. 4.The algorithm showed that the seasonal demand for food peaked in both species in the second half of the breeding season and, for macaroni penguins, there was a second peak immediately after moult. Minimum food demand occurred in both species during the first half of the breeding season. 5. As both Antarctic fur seals and macaroni penguins compete for krill with a commercial fishery, these results provide an insight into the seasons and stages of the life cycle in which competition is likely to be greatest.

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Section: Methodsmentioning

confidence: 99%

Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguins

Boyd¹

2002

Journal of Applied Ecology

104

101

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“…The mass-specific body water pools were similar for chicks and adults, but the estimates for the latter were significantly higher (ANOVA: Fl,~0 = 19.57; P< 0.0025) than those of gentoo penguins feeding chicks at South Georgia (Davis et al 1983). Since the body weights for adults between study areas were similar, the difference in percentage of body water possibly reflects a difference in amount of body fat in birds between study areas, the South Georgian birds being fatter.…”

Section: Discussionmentioning

confidence: 85%

“…By comparison, adult gentoo penguins at South Georgia (where the energy content of the diet is higher than that of gentoos at Macquarie Island) consumed 1.1 kg-day -1 (estimated from Davis et al 1983), which is similar to the amount of food consumed by adult 3. In a diet study at Macquarie Island the mass of stomach contents of 26 water-offloaded gentoo penguins feeding chicks two weeks older than those studied here averaged 492g and ranged from 58-1230g (Robertson and Williams, in preparation).…”

Section: Discussionmentioning

confidence: 87%

“…Since the recent development of isotope turnover techniques (e.g., Nagy t975), feeding rates and energy requirements have been estimated for king (Aptenodytes patagonicus) (Kooyman et al 1982), gentoo (Pygoscelispapua) (Davis et al 1983), macaroni (Eudyptes chrysolophus) (Davis et al 1983), jackass (Spheniscus demersus) (Nagy et al 1984) and little penguins (Eudyptula minor) (Costa et al 1986). Since the recent development of isotope turnover techniques (e.g., Nagy t975), feeding rates and energy requirements have been estimated for king (Aptenodytes patagonicus) (Kooyman et al 1982), gentoo (Pygoscelispapua) (Davis et al 1983), macaroni (Eudyptes chrysolophus) (Davis et al 1983), jackass (Spheniscus demersus) (Nagy et al 1984) and little penguins (Eudyptula minor) (Costa et al 1986).…”

Section: Introductionmentioning

confidence: 99%

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Estimated feeding rates and energy requirements of gentoo penguins, Pygoscelis papua, at Macquarie Island

1988

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Water and sodium turnovers of 6-7 week old gentoo penguin chicks and breeding adults were measured using isotopically labelled water and sodium. Influx rates for chicks averaged 188ml.kg-l.day -1 and 13.9mmol.kg-l'day -1 for water and sodium, respectively. Chicks consumed an estimated 228 g. kg-1. day-1 fresh food or 886 kJ kg-1 day. These values correspond to 761 g.day -1 or 2945kJ.day -1 for a gentoo chick mid-way through the growth period. Flux rates for adults attending chicks ranged from 199 to 428 ml. kg-1. day-1 for water and from 15 to 36mmol.kg-l.day -1 for sodium.

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“…T h e implications of sea-water ingestion are treated in the discussion. Similar estimates of prey intake in penguins via water influx measurements gave realistic rates of food ingestion and it is unlikely that significant sea-water ingestion occurred (Kooyman et al 1982, Davis et al 1983. Furthermore, validation studies on pinnipeds indicate excellent agreement between actual food intake and food intake estimated from water influx measurements (differences of -2.3 yo in Northern Fur Seals Callorhinus ursinus (Costa & Gentry 1986) and 1 and 10% in California Sea Lions Zalophus californianus (Costa 1984).…”

Section: Food Intakementioning

confidence: 81%

Foraging energetics of Grey‐headed Albatrosses Diotnedea chrysostoma at Bird Island, South Georgia

Costa

Prince

1987

Ibis

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At-sea metabolism (CO2 production) and water turnover of six breeding Grey-headed Albatrosses Diomedea chrysostoma were measured, using the doubly labelled water method, at Bird Island, South Georgia. Mean food consumption (estimated from a water influx rate of 1.01 1 d -' and data on dietary composition) was 12001: d^ ' or 50.4 W. At-sea metabolism (derived from a rate of COz production of 3.98 1 h-') was 27.7 W, 2.5 times the estimated basal metabolic rate (BMR). On average the birds ingested nearly twice as much food energy as they expended to obtain it. The metabolic rate during flight (estimated from at-sea metabolism and activity budget data) was 36.3 W (range 34.7-39.0 W) or 3.2 (range 3.Cb3.4) times the predicted BMR. This is the lowest cost of flight yet measured, but consistent with the highly developed adaptations for economic flight shown by albatrosses. These results are briefly compared with data for other polar vertebrates (penguins, fur seals) exploiting similar prey.A significant part of the costs to parents of rearing offspring is the energy consumed in foraging activities. These costs are likely to be particularly important in species which need to travel long distances (e.g., because they feed on widely dispersed resources) and in species using energetically expensive modes of locomotion (e.g., flapping flight). Although field studies of energy expenditure have been carried out on a variety of birds and mammals (e.g., Mullen 1970, Utter & Lefebvre 1972, Shoemaker et al. 1976, Bryant & Westerterp 1983, little attention has been given to species adapted for long-distance travel. Of birds, pelagic seabirds of the Order Procellariiformes contain many such species and pre-eminent amongst these, in terms of specializations for economy of long-distance flight, are the albatrosses Diomedeidae, which are essentially dependent on soaring and gliding (Pennycuick 1975(Pennycuick , 1982(Pennycuick , 1986. T h e metabolic rate during free-ranging gliding flight has not yet been estimated for any bird; the energy costs of foraging trips have not been measured for any procellariform and there is only one previous study of a seabird, the Sooty T e r n Sterna fusrata (Flint & Nagy 1984).We used the doubly labelled water method, coupled with behavioural and dietary data, to measure the rate of water and energy flux in breeding Grey-headed Albatrosses Diomedea chrysostoma making foraging trips to sea from Bird Island, South Georgia (54"00'S, 38'02'W) during the austral summer of 1983-84. This species has been extensively studied at this site and much information is available on its reproductive biology and ecology (reviewed in Prince 1985), including unique data on activity budgets at sea (Prince & Francis 1984).

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Water flux and estimated metabolism of free-ranging gentoo and macaroni penguins at South Georgia

Cited by 39 publications

References 22 publications

Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguins

Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguins

Estimated feeding rates and energy requirements of gentoo penguins, Pygoscelis papua, at Macquarie Island

Foraging energetics of Grey‐headed Albatrosses Diotnedea chrysostoma at Bird Island, South Georgia

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