Energy intake and utilisation by nursing bearded seal (Erignathus barbatus) pups from Svalbard, Norway

Lydersen, Christian; Kovacs, Kit M.; Hammill, Mike O.; Gjertz, Ian

doi:10.1007/bf02337884

Cited by 40 publications

(13 citation statements)

References 34 publications

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“…Field metabolic rates (FMR) for 23‐month Australian sea lions were 3·95 times basal metabolic rates (BMR) predicted for adult terrestrial animals of equivalent size (Kleiber 1975). Although this is the first study to measure FMR in a juvenile sea lion, results fall within the range of rates reported for young pinnipeds (phocids: 2·7–6·0 times BMR (Reilly 1991; Kretzmann, Costa & LeBoeuf 1993; Lydersen & Hammill 1993; Lydersen & Kovacs 1996; Lydersen et al. 1996), otariids: 3·25–3·84 times BMR (Arnould et al.…”

Section: Discussionsupporting

confidence: 81%

Ontogeny of oxygen stores and physiological diving capability in Australian sea lions

et al. 2007

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Summary 1.For air-breathing animals in aquatic environments, foraging behaviours are often constrained by physiological capability. The development of oxygen stores and the rate at which these stores are used determine juvenile diving and foraging potential. 2. We examined the ontogeny of dive physiology in the threatened Australian sea lion Neophoca cinerea. Australian sea lions exploit benthic habitats; adult females demonstrate high field metabolic rates (FMR), maximize time spent near the benthos, and regularly exceed their calculated aerobic dive limit (cADL). Given larger animals have disproportionately greater diving capabilities; we wanted to determine the extent physiological development constrained diving and foraging in young sea lions. 3. Ten different mother/pup pairs were measured at three developmental stages (6, 15 and 23 months) at Seal Bay Conservation Park, Kangaroo Island, South Australia. Hematocrit (Hct), haemoglobin (Hb) and plasma volume were analyzed to calculate blood O 2 stores and myoglobin was measured to determine muscle O 2 . Additionally, FMR's for nine of the juveniles were derived from doubly-labelled water measurements. 4. Australian sea lions have the slowest documented O 2 store development among diving mammals. Although weaning typically occurs by 17·6 months, 23-month juveniles had only developed 68% of adult blood O 2 . Muscle O 2 was the slowest to develop and was 60% of adult values at 23 months. 5. We divided available O 2 stores (37·11 ± 1·49 mL O 2 kg − 1 ) by at-sea FMR (15·78 ± 1·29 mL O 2 min − 1 kg − 1 ) to determine a cADL of 2·33 ± 0·24 min for juvenile Australian sea lions. Like adults, young sea lions regularly exceeded cADL's with 67·8 ± 2·8% of dives over theoretical limits and a mean dive duration to cADL ratio of 1·23 ± 0·10. 6. Both dive depth and duration appear impacted by the slow development of oxygen stores. For species that operate close to, or indeed above their estimated physiological maximum, the capacity to increase dive depth, duration or foraging effort would be limited. Due to reduced access to benthic habitat and restricted behavioural options, young benthic foragers, such as Australian sea lions, would be particularly vulnerable to resource limitation.

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Section: Discussionsupporting

confidence: 81%

Ontogeny of oxygen stores and physiological diving capability in Australian sea lions

et al. 2007

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“…Burns (1981) claimed that weaning in bearded seals is abrupt, with the pups simply being deserted by their mothers. In contrast, Lydersen et al (1996) suggested that bearded seal pups may suckle longer than some other phocid pups and that weaning is less abrupt than among other phocid species. A mixture of milk and prey has been recorded in bearded seal pup stomachs (RoÈ mer and Schaudinn 1900), which indicates that pups commence foraging while still being nursed.…”

Section: Introductionmentioning

confidence: 95%

Movements and diving of bearded seal ( Erignathus barbatus ) mothers and pups during lactation and post-weaning

et al. 2000

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Eleven bearded seals (Erignathus barbatus) were tagged with satellite-linked dive recorders in Kongsfjorden, Svalbard, Norway, in May 1994. These animals included four mother-pup pairs and three single pups. The seals were tracked for 21±258 days. A total of 207,000 dives were recorded. Bearded seal mothers showed limited movements during the nursing and moulting periods. After weaning, the pups moved out of the tagging area and dispersed coastally. One pup left Svalbard and moved far oshore to Greenland and Jan Mayen. Bearded seal adults displayed a bi-modal dive behaviour, with peaks of activity that were shallower than 10 m or from 50 to 70 m. Most dives for adult seals (97%) were shorter than 10 min. Young pups performed dives that were shallower and shorter in duration than their accompanying mothers, but diving skills improved rapidly with age. Six of the seven pups dived deeper than 448 m by the time they were 2 months old. Analyses of movement data with respect to separation of motherpup pairs suggest a lactation period of about 24 days.

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“…However, during the past decade concerted efforts have greatly increased our knowledge of bearded seal natural history, and their importance to arctic ecosystems (e.g. Hammill et al, 1994; Lydersen Kovacs et al, 1996;Lydersen et al, 1996;Andersen et al, 1999;Lydersen and Kovacs, 1999;Gjertz et al, 2000;Krafft et al, 2000;Lydersen et al, 2001;Marshall et al, 2001;Van Parijs et al, 2001;Lydersen et al, 2002;Van Parijs et al, 2003;Van Parijs et al, 2004;Davies et al, 2006;Marshall et al, 2006;Van Parijs and Clark, 2006;Dehn et al, 2007;Risch et al, 2007). Analyses of stomach contents and recent stable isotope analyses demonstrate that bearded seals are generalist foragers (e.g.…”

Section: Introductionmentioning

confidence: 99%

Feeding kinematics, suction and hydraulic jetting capabilities in bearded seals (Erignathus barbatus)

Marshall

Kovacs

Lydersen

2008

Journal of Experimental Biology

147

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SUMMARYFeeding kinematics, suction and hydraulic jetting capabilities of bearded seals (Erignathus barbatus) were characterized during controlled feeding trials. Feeding trials were conducted both on land and in water, and allowed a choice between suction and biting, but food was also presented that could be ingested by suction alone. Four feeding phases, preparatory, jaw opening, hyoid depression and jaw closing were observed; the mean feeding cycle duration was 0.54±0.22·s, regardless of feeding mode (P>0.05). Subjects feeding on land used biting and suction 89.3% and 10.7% of the time, respectively. Subjects feeding in water used suction and hydraulic jetting 96.3% and 3.7% of the time, respectively. No biting behavior was observed underwater. Suction feeding was characterized by a small gape (2.7±0.85·cm), small gape angle (24.4±8.13°), pursing of the rostral lips to form a circular aperture, and pursing of the lateral lips to occlude lateral gape. Biting was characterized by large gape (7.3±2.2·cm), large gape angle (41.7±15.2°), and lip curling to expose the teeth. An excavation behavior in which suction and hydraulic jetting were alternated was used to extract food from recessed wells. The maximum subambient and suprambient pressures recorded were 91.2 and 53.4·kPa, respectively. The inclusion of suction data for phocids broadens the principle that suction feeding kinematics is conserved among aquatic vertebrates. Furthermore, bearded seals support predictions that mouth size, fluid flow speed, and elusiveness of prey consumed are among a suite of traits that determine the specific nature of suction feeding among species.

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Energy intake and utilisation by nursing bearded seal (Erignathus barbatus) pups from Svalbard, Norway

Cited by 40 publications

References 34 publications

Ontogeny of oxygen stores and physiological diving capability in Australian sea lions

Ontogeny of oxygen stores and physiological diving capability in Australian sea lions

Movements and diving of bearded seal ( Erignathus barbatus ) mothers and pups during lactation and post-weaning

Feeding kinematics, suction and hydraulic jetting capabilities in bearded seals (Erignathus barbatus)

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