Age, body mass and environmental variation shape the foraging ontogeny of Galapagos sea lions

Jeglinski, Jana W. E.; Werner, Christiane; Robinson, Patrick W.; Costa, Daniel P.; Trillmich, Fritz

doi:10.3354/meps09649

Cited by 68 publications

(64 citation statements)

References 101 publications

(121 reference statements)

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“…Although there are no published accounts of the diving behaviors of immature walruses for comparison, studies on other pinnipeds have demonstrated shorter dive durations, shallower dive depths and a lower percentage of time spent diving by immature seals compared with adult conspecifics (Thorson, 1993;Lydersen and Hammill, 1993;Lydersen et al, 1994;Horning and Trillmich, 1997;McCafferty et al, 1998;Bowen et al, 1999;Burns, 1999;Greaves et al, 2005;Fowler et al, 2006;Rehberg and Burns, 2008). The dive durations of immature pinnipeds increase with age as body size increases (Kooyman et al, 1983;Lydersen and Hammill, 1993;Thorson, 1993;Lydersen et al, 1994;Burns and Castellini, 1996;Burns et al, 1998;Horning and Trillmich, 1997;Burns et al, 1998;Costa et al, 1998;McCafferty et al, 1998;Burns, 1999), and these ontogenetic differences in diving capacity have been associated with inter-age class variations in diet (Bowen et al, 1999;Field et al, 2007;Jeglinski et al, 2012). Yet, unlike these other pinnipeds, independent juvenile walruses consume the same prey as adults, as suggested by their stomach contents (Fay, 1982), which could result in competition between juvenile and adult walruses for food if prey became limited.…”

Section: Diving Capacity Of Walrusesmentioning

confidence: 99%

Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

Noren

Jay

Burns

et al. 2015

Journal of Experimental Biology

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Physiological constraints dictate animals' ability to exploit habitats. For marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. We characterized age-specific dive limits of walruses by measuring anaerobic (acid-buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. Mean buffering capacities were similar across muscles and age classes (a fetus, five neonatal calves, a 3 month old and 20 adults), ranging from 41.31 to 54.14 slykes and 42.00 to 46.93 slykes in the longissimus and supraspinatus, respectively. Mean myoglobin in the fetus and neonatal calves fell within a narrow range (longissimus: 0.92-1.68 g 100 g −1 wet muscle mass; supraspinatus: 0.88-1.64 g 100 g −1 wet muscle mass). By 3 months post-partum, myoglobin in the longissimus increased by 79%, but levels in the supraspinatus remained unaltered. From 3 months post-partum to adulthood, myoglobin increased by an additional 26% in the longissimus and increased by 126% in the supraspinatus; myoglobin remained greater in the longissimus compared with the supraspinatus. Walruses are unique among marine mammals because they are born with a mature muscle acid-buffering capacity and attain mature myoglobin content early in life. Despite rapid physiological development, small body size limits the diving capacity of immature walruses and extreme sexual dimorphism reduces the diving capacity of adult females compared with adult males. Thus, free-ranging immature walruses likely exhibit the shortest foraging dives while adult males are capable of the longest foraging dives.

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Section: Diving Capacity Of Walrusesmentioning

confidence: 99%

Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

Noren

Jay

Burns

et al. 2015

Journal of Experimental Biology

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“…Particularly important in this regard is our assumption that the foraging competence of young seals developed only after weaning, thereby being related only to the time since weaning and not to the age of the pups as well. Otariid pups typically reach independence after many months of active learning, swimming, and diving (e.g., Fowler et al 2006, Jeglinski et al 2012. Moreover, the intensity of active learning appears to be higher among species reaching independence at a younger age (Arnould et al 2003).…”

Section: Effects Of Food Supplymentioning

confidence: 99%

Capital and income breeding: the role of food supply

Stephens

Houston

Hårding

et al. 2014

Ecology

101

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Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract. An aspect of life history that has seen increasing attention in recent years is that of strategies for financing the costs of offspring production. These strategies are often described by a continuum ranging from capital breeding, in which costs are met purely from endogenous reserves, to income breeding, in which costs are met purely from concurrent intake. A variety of factors that might drive strategies toward a given point on the capitalincome continuum has been reviewed, and assessed using analytical models. However, aspects of food supply, including seasonality and unpredictability, have often been cited as important drivers of capital and income breeding, but are difficult to assess using analytical models. Consequently, we used dynamic programming to assess the role of the food supply in shaping offspring provisioning strategies. Our model is parameterized for a pinniped (one taxon remarkable for the range of offspring-provisioning strategies that it illustrates). We show that increased food availability, increased seasonality, and, to a lesser extent, increased unpredictability can all favor the emergence of capital breeding. In terms of the conversion of energy into offspring growth, the shorter periods of care associated with capital breeding are considerably more energetically efficient than income breeding, because shorter periods of care are associated with a higher ratio of energy put into offspring growth to energy spent on parent and offspring maintenance metabolism. Moreover, no clear costs are currently associated with capital accumulation in pinnipeds. This contrasts with general assumptions about endotherms, which suggest that income breeding will usually be preferred. Our model emphasizes the role of seasonally high abundances of food in enabling mothers to pursue an energetically efficient capital-breeding strategy. We discuss the importance of offspring development for dictating strategies for financing offspring production.

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“…Loggers were glued onto neoprene, fixed to a piece of mesh using cable ties and attached to the fur of the animals using a fast-drying epoxy (Araldite 2012, Huntsmann Advanced Materials). Instruments were recovered by recapturing the animals 48.6 ± 11.6 d after deployment, and loggers, as well as the neoprene and mesh, glued to the fur were removed (Horning & Trillmich 1997, Jeglinski et al 2012. The epoxy stayed on the animals only until they moulted.…”

Section: Methodsmentioning

confidence: 99%

Proximity loggers on amphibious mammals: a new method to study social relations in their terrestrial habitat

Meise

Krüger²,

Piedrahíta³

et al. 2013

Aquat. Biol.

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Amphibious mammal species alternate between foraging at sea and attendance on land. Due to thermoregulatory requirements, they often haul out during the night, making social interactions difficult to observe. We tested the suitability of UHF-proximity loggers for assessing social relationships among Galápagos sea lions Zalophus wollebaeki. To survive periods at sea, proximity loggers were embedded in epoxy. Automatic downloads to receiving stations rendered logger recovery unnecessary. Encounters were logged within a range of 10 m. Logs provided information about interacting individuals as well as time and duration of encounters. 'Received signal strength indicator' values correlated with distance, but were influenced by antenna angle and environmental factors. Laboratory tests and validation in the field demonstrated that the spatial resolution corresponded to 2 m. Data needed to be corrected, as single encounters were recorded as multiple logs and reciprocity of loggings between animals was not always achieved. Digital data correlated with observational data, but associations were 4 times more likely to be detected using proximity loggers. Data revealed that non-territorial males frequently associated for extended periods of time, especially during the night and even outside the study colony. The modified proximity logger system proves an excellent tool to determine social structure in situations where direct observation is limited. KEY WORDS: Amphibious species · Proximity logger · Social structureResale or republication not permitted without written consent of the publisher AQUATIC BIOLOGY

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Age, body mass and environmental variation shape the foraging ontogeny of Galapagos sea lions

Cited by 68 publications

References 101 publications

Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

Capital and income breeding: the role of food supply

Proximity loggers on amphibious mammals: a new method to study social relations in their terrestrial habitat

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