Resting and swimming metabolic rates in juvenile walruses (<scp><i>Odobenus rosmarus</i></scp>)

Rosen, David A. S.

doi:10.1111/mms.12743

Cited by 6 publications

(5 citation statements)

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“…The mean RMR of walruses while fasted out of water (2.6× Kleiber) was slightly higher than the highest estimates for a juvenile male and female walrus (2.3 and 2.4, respectively; Rosen, 2020) and at the highest range (1.1–2.5) used in the energy model developed by Udevitz et al (2017) suggesting that RMRs for adult Pacific walruses may be higher than previously thought. These higher RMRs are consistent with otters, pinnipeds, and cetaceans, which tend to have a 1.4–2.9 times higher RMR compared to that predicted for terrestrial mammals of similar body mass (i.e., Kleiber ratios).…”

Section: Discussionmentioning

confidence: 62%

“…The greater increase in metabolic rate for sea lions while swimming versus hauled out may be a result of higher relative swimming speeds. Rosen (2020) noted that both estimated locomoter costs and total cost of transport for the two juvenile walruses swimming in his study were greater than that predicted by an interspecific relationship for marine mammals. Rosen (2020) suggested this could be a result of suboptimal swimming speeds or not being very streamlined, factors that might have differed for the juvenile walruses in his study compared to the adult females in ours.…”

Section: Discussionmentioning

confidence: 83%

“…For example, the metabolic rates of fasted Southern sea lions ( Otaria byronia ) while subsurface swimming were 135% higher than metabolic rates while hauled out on land (Dassis et al, 2012). Juvenile walruses similarly exhibited increases in metabolic rates of 25%–55% when subsurface swimming compared to resting at the water surface (Rosen, 2020). However, fasted adult female walruses in the current and our past study (Borque‐Espinosa et al, 2021a) had metabolic rates just 25% higher when swimming compared to when hauled out after fasting (Figure 1) and therefore, at the lower end of what was reported for juvenile walruses.…”

Section: Discussionmentioning

confidence: 99%

“…An energetic model was developed to understand the implications of changes in behavior on the energetics of Pacific walruses in response to Arctic sea ice loss (Udevitz et al, 2017), but the behavior‐specific metabolic rates that are needed to develop a precise model for adult walruses have been lacking. Rosen (2020) measured active and resting metabolic rates of two juvenile Pacific walruses. Borque‐Espinosa et al (2021a) began to address the need for data from adult walruses by quantifying the metabolic costs of three adult female Pacific walruses while swimming, diving, and resting in water.…”

Section: Introductionmentioning

confidence: 99%

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Effects of feeding and habitat on resting metabolic rates of the Pacific walrus

Rode,

Rocabert,

Borque‐Espinosa

et al. 2023

Marine Mammal Science

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Arctic marine mammals live in a rapidly changing environment due to the amplified effects of global warming. Pacific walruses (Odobenus rosmarus divergens) have responded to declines in Arctic sea‐ice extent by increasingly hauling out on land farther from their benthic foraging habitat. Energy models can be useful for better understanding the potential implications of changes in behavior on body condition and reproduction but require behavior‐specific metabolic rates. Here we measured the resting metabolic rates (RMR) of three captive, adult female Pacific walruses through breath‐by‐breath respirometry when fed and fasted resting out of water (sitting and lying down) and while fed resting in water. RMR in and out of water were positively related with pretrial energy intake when not fasted and 25% higher than RMR when walruses were fasted and out of water. Overall, RMR was higher than previously estimated for this species. Fasting RMR out of water was only 25% lower than subsurface swimming metabolic rates suggestive of relatively efficient swimming in adult females. Our results identify the importance of considering feeding status and species‐specific differences in affecting metabolic costs. Further research is needed to better understand potential energetic costs of thermoregulation at temperatures experienced by wild walruses.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of feeding and habitat on resting metabolic rates of the Pacific walrus

Rode,

Rocabert,

Borque‐Espinosa

et al. 2023

Marine Mammal Science

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“…Meanwhile, there is only a single published study for a mature odobenid, the walrus ( Odobenus rosmarus ; Borque-Espinosa et al, 2021 ). They reported a relatively high BMR (2.9 x Kleiber) compared to the other marine mammals, and this value was curiously higher than the RMR (1.9 x Kleiber) reported for two juvenile walrus ( Rosen, 2020 ). As noted by Borque-Espinosa et al (2021) , the elevated BMR in the adult walrus may have been related to the animal being somewhat active during testing.…”

Section: What Are the Metabolic Rates Of Marine Mammals If We Only Co...mentioning

confidence: 65%

What are the Metabolic Rates of Marine Mammals and What Factors Impact this Value: A review

Noren,

Rosen

2023

Conservation Physiology

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Over the past several decades, scientists have constructed bioenergetic models for marine mammals to assess potential population-level consequences following exposure to a disturbance, stressor, or environmental change, such as under the Population Consequences of Disturbance (pCOD) framework. The animal's metabolic rate (rate of energy expenditure) is a cornerstone for these models, yet the cryptic lifestyles of marine mammals, particularly cetaceans, have limited our ability to quantify basal (BMR) and field (FMR) metabolic rates using accepted ‘gold standard’ approaches (indirect calorimeter via oxygen consumption and doubly labeled water, respectively). Thus, alternate methods have been used to quantify marine mammal metabolic rates, such as extrapolating from known allometric relationships (e.g. Kleiber's mouse to elephant curve) and developing predictive relationships between energy expenditure and physiological or behavioral variables. To understand our current knowledge of marine mammal metabolic rates, we conducted a literature review (1900–2023) to quantify the magnitude and variation of metabolic rates across marine mammal groups. A compilation of data from studies using ‘gold standard’ methods revealed that BMR and FMR of different marine mammal species ranges from 0.2 to 3.6 and 1.1 to 6.1 x Kleiber, respectively. Mean BMR and FMR varied across taxa; for both measures odontocete levels were intermediate to higher values for otariids and lower values of phocids. Moreover, multiple intrinsic (e.g. age, sex, reproduction, molt, individual) and extrinsic (e.g. food availability, water temperature, season) factors, as well as individual behaviors (e.g. animal at water’s surface or submerged, activity level, dive effort and at-sea behaviors) impact the magnitude of these rates. This review provides scientists and managers with a range of reliable metabolic rates for several marine mammal groups as well as an understanding of the factors that influence metabolism to improve the discernment for inputs into future bioenergetic models.

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