Condition and mass impact oxygen stores and dive duration in adult female northern elephant seals

Hassrick, Jason L.; Crocker, Daniel E.; Teutschel, Nicole M.; McDonald, Birgitte I.; Robinson, Patrick W.; Simmons, Samantha E.; Costa, Daniel P.

doi:10.1242/jeb.037168

Cited by 88 publications

(82 citation statements)

References 61 publications

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“…In the Indian Ocean sector, this zone broadens latitudinally in the Kerguelen region (Orsi et al 1995) and this sector seems to represent a large region of un favourable foraging conditions for SES. Despite our results supporting previous findings that dive capacity increases throughout the duration of the foraging trips (Bennett et al 2001, Hassrick et al 2010, Mc Intyre et al 2011b), both T 200 and diving depth were also found to influence dive duration in the present study.…”

Section: Discussioncontrasting

confidence: 54%

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

Guinet¹,

Vacquié‐Garcia²,

Picard³

et al. 2014

Mar. Ecol. Prog. Ser.

102

131

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The distribution of southern elephant seal Mirounga leonina prey encounter events (PEEs) was investigated from the foraging behaviour of 29 post-breeding females simultaneously equipped with a satellite tag, a time−depth recorder and a head-mounted accelerometer. Seal diving depth and PEE were related to water temperature at 200 m (T 200 ), and light level at the surface (L 0 ) and at depth. Approximately half (49%) of all dives were located in waters encompassed between the southern Antarctic Circumpolar Current Front and the Polar Front. Seals dived significantly deeper during the day than at night. Diving and PEE depth increased with increasing T 200 and for a given T 200 according to L 0 and the percentage of surface light reaching 150 m. On average, 540 PEEs per day were recorded. Seals exhibited more PEEs per unit of time spent diving during the twilight period compared with at night, and were least successful during daylight hours. Elephant seals forage in T 200 ranging between −1 and 13°C; however, few PEEs were recorded at depths shallower than 400−500 m at night when the T 200 exceeded 8°C. The diet of female Kerguelen elephant seals appears to be dominated by myctophids (lanternfish), and according to the average mass of their most likely myctophid prey (9 g, Electrona calsbergi and E. antarctica; 30 g Gymnoscopelus nicholsi and G. piabilis), we estimate that seals consumed 4.8−16.1 kg of fish daily. Despite lower catch rates in warmer waters, no relationship was found between the mean T 200 at the scale of the foraging trip and daily or absolute mass gain, suggesting that elephant seals are compensating for lower catch rates by consuming larger/richer prey items in those waters.

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Section: Discussioncontrasting

confidence: 54%

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

Guinet¹,

Vacquié‐Garcia²,

Picard³

et al. 2014

Mar. Ecol. Prog. Ser.

102

131

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“…Muscle O 2 stores, as indicated by Mb concentrations, were higher than previously reported in Weddell seals (Ponganis et al 1993;Kanatous et al 2002;Hindle et al 2011), but were also maintained across the winter. As muscle Mb loads often correlate with dive durations (Noren and Williams 2000;Lestyk et al 2009), higher Mb concentrations in deep-diving Weddell seals make their O 2 -storage capacities more similar to those previously reported in other phocid species capable of extended breath hold diving Lestyk et al 2009;Hassrick et al 2010). That Weddell seals expend energy to continue producing equivalent RBCs and iron-containing O 2 -carrying proteins during all times of the year (i.e., reduced and intense foraging periods, and the energetically expensive molt period), and also through senescence (Hindle et al 2009 demonstrates the importance of maintaining aerobic diving capacities.…”

Section: Discussionsupporting

confidence: 71%

“…In contrast to otariids, the Phocidae family appears to follow a different pattern. In addition to TBO 2 and muscle biochemistry being conserved in Weddell seals, the northern elephant seal (Mirounga angustirostris) did not exhibit any changes in factors contributing to TBO 2 or the cADL across the post-molt or post-breeding foraging trips (Hassrick et al 2010), and studies show that harbor seal (Phoca vitulina) muscle biochemistry does not change seasonally (Burns unpublished). Weddell seals and other phocids forage on unreliable prey resources spanning great distances in order to accumulate some or all of the reserves necessary for energetically costly periods of reproduction and the annual molt (Costa and Shaffer 2012).…”

mentioning

confidence: 99%

Scaling matters: incorporating body composition into Weddell seal seasonal oxygen store comparisons reveals maintenance of aerobic capacities

2015

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β-hydroxyacyl CoA dehydrogenase) were likewise maintained across the year. The preservation of aerobic capacity is likely critical to foraging capabilities, so that following the molt Weddell seals can rapidly regain body mass at the start of winter foraging. In contrast, muscle lactate dehydrogenase activity, a marker of anaerobic metabolism, exhibited seasonal plasticity in this diving top predator and was lowest after the summer period of reduced activity. Total body oxygen stores Abstract Adult Weddell seals (Leptonychotes weddellii) haul-out on the ice in October/November (austral spring) for the breeding season and reduce foraging activities for ~4 months until their molt in the austral fall (January/February). After these periods, animals are at their leanest and resume actively foraging for the austral winter. In mammals, decreased exercise and hypoxia exposure typically lead to decreased production of O 2 -carrying proteins and muscle wasting, while endurance training increases aerobic potential. To test whether similar effects were present in marine mammals, this study compared the physiology of 53 post-molt female Weddell seals in the austral fall to 47 pre-breeding females during the spring in McMurdo Sound, Antarctica. Once body mass and condition (lipid) were controlled for, there were no seasonal changes in total body oxygen (TBO 2 ) stores. Within each season, hematocrit and hemoglobin values were negatively correlated with animal size, and larger animals had lower mass-specific TBO 2 stores. But because larger seals had lower mass-specific metabolic rates, their calculated aerobic dive limit was similar to smaller seals. Indicators of muscular efficiency, myosin heavy chain composition, myoglobin concentrations, and aerobic enzyme activities (citrate synthase and Keywords

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“…For example, seals may prolong bottom duration to increase foraging effort in richer feeding grounds, an idea supported by theoretical and empirical studies on the diving behaviour of some seal species [7,49]. Second, changes in body size may affect bottom duration, because large body mass increases oxygen-carrying capacity while simultaneously reducing the rate of oxygen use, allowing seals to stay underwater longer [50,51]. Third, seasonal hypometabolism (i.e.…”

Section: Discussion (A) Buoyancy Determines Locomotor Costs Of Swimmingmentioning

confidence: 99%

The foraging benefits of being fat in a highly migratory marine mammal

et al. 2014

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Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animalborne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat.

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Condition and mass impact oxygen stores and dive duration in adult female northern elephant seals

Cited by 88 publications

References 61 publications

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

Scaling matters: incorporating body composition into Weddell seal seasonal oxygen store comparisons reveals maintenance of aerobic capacities

The foraging benefits of being fat in a highly migratory marine mammal

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