Utilization of stored energy reserves during fasting varies by age and season in Steller sea lions

2007 ◽  
Vol 85 (2) ◽  
pp. 190-200 ◽  
Author(s):  
L.D. Rea ◽  
D.A.S. Rosen ◽  
A.W. Trites
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Breeding Season ◽  
Lower Percentage ◽  
Metabolic Adaptation ◽  
Body Lipid ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Nonbreeding Season ◽  
Total Body

Nine captive Steller sea lions ( Eumetopias jubatus (Schreber, 1776), 1.75–6 years of age) were fasted for 7–14 d to test the effect of short-term fasting on changes in body mass and body condition. Trials were repeated during both the summer breeding season and the nonbreeding season in seven animals to elucidate whether there was a seasonal component to the ability of Steller sea lions to adapt to limited food resources. Mean percent mass loss per day was higher during the breeding season in juveniles (1.8% ± 0.2%·d–1) than in subadults (1.2% ± 0.1%·d–1), but there were no significant age-related differences during the nonbreeding season (juveniles, 1.5% ± 0.3%·d–1; subadults, 1.7% ± 0.3%·d–1). A decrease in the rate of mass loss occurred after the first 3 d of fasting only in subadults during the breeding season. Percent total body lipid ranged from 11% to 28% of total body mass at the initiation of fasting trials. Animals with lower initial percent total body lipid exhibited higher subsequent rates of mass loss and a lower percentage of tissue catabolism derived from lipid reserves. There was no evidence of metabolic adaptation to fasting in juveniles, which suggests that juvenile sea lions would be more negatively impacted by food limitation during the breeding season than would subadults.

Comparing total body lipid content of young-of-the-year Steller sea lions among regions of contrasting population trends

2016 ◽  
Vol 32 (4) ◽  
pp. 1200-1218 ◽  
Author(s):  
Lorrie D. Rea ◽  
Brian S. Fadely ◽  
Sean D. Farley ◽  
Julie P. Avery ◽  
Wendy S. Dunlap-Harding ◽  
...  
Keyword(s):  
Lipid Content ◽  
Population Trends ◽  
Body Lipid ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Young Of The Year ◽  
Total Body

Reproductive effort of male hooded seals (Cystophora cristata): estimates from mass loss

1996 ◽  
Vol 74 (8) ◽  
pp. 1521-1530 ◽  
Author(s):  
Kit M. Kovacs ◽  
Christian Lydersen ◽  
Mike Hammill ◽  
David M. Lavigne
Keyword(s):  
Body Composition ◽  
Mass Loss ◽  
Body Mass ◽  
Breeding Season ◽  
Tritiated Water ◽  
Dive Depth ◽  
Dive Duration ◽  
Day Range ◽  
Ice Surface ◽  
Cystophora Cristata

This study investigated mass loss, body composition, and behaviour patterns of male hooded seals during the reproductive season. During the 6 years of study (between 1989 and 1995), 139 records of male mass were obtained that involved 115 individuals. Body masses of males ranged from 147 to 434 kg. Mean mass at first capture was 312.5 ± 53.0 kg (N = 119). Year, date of sampling, and age all significantly influenced mass. Nineteen males were recaptured at least twice during a single season. Mean rate of mass loss among these individuals was 2.5 ± 1.1 kg/day (range 0.7–4.6 kg/day). Body composition early in the breeding season, measured using tritiated water (N = 6), produced mean estimates of 51.6 ± 1.6% water, 29.3 ± 2.4% fat, 16.9 ± 0.7% protein, and 1.9 ± 0.2% ash. Time–depth recorders attached to three males indicated that they spent 84.7 ± 15.4% of their time hauled out on the surface of the ice during the breeding season. Each of these males was on the ice for a few days; they then spent a few hours at sea before returning to the ice surface. Mean dive depth was only 14.1 ± 3.2 m (maximum 66 m) and mean dive duration was only 1.7 ± 0.3 min (maximum 28 min). Extrapolating mean daily rates of body mass loss to encompass a 2.5-week breeding season, males would lose an average of 44 kg, which represents 14% of their mean body mass. Compared with values for males of other phocid species this value is conservative. It appears that the short breeding season among hooded seals is energetically advantageous for both sexes.

Foraging behavior of adult female Steller sea lions during the breeding season in Southeast Alaska

2009 ◽  
Vol 25 (3) ◽  
pp. 588-604 ◽  
Author(s):  
M. J. Rehberg ◽  
R. D. Andrews ◽  
U. G. Swain ◽  
D. G. Calkins
Keyword(s):  
Foraging Behavior ◽  
Breeding Season ◽  
Adult Female ◽  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Sea Lions

Pollock and the decline of Steller sea lions: testing the junk-food hypothesis

2000 ◽  
Vol 78 (7) ◽  
pp. 1243-1250 ◽  
Author(s):  
David AS Rosen ◽  
Andrew W Trites
Keyword(s):  
Body Mass ◽  
Energy Content ◽  
Gulf Of Alaska ◽  
Aleutian Islands ◽  
Net Energy ◽  
Junk Food ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Gross Energy

The decline of Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska and the Aleutian Islands may be the result of them eating too much pollock (a gadid fish) instead of a more balanced and diverse diet containing fattier fishes, such as herring or sandlance. We sought to test this junk-food hypothesis by feeding six captive Steller sea lions (ages 0.9-4.5 years) only pollock or herring. All sea lions gained mass while eating herring. However, eating only pollock for short periods (11-23 d) caused the study animals to lose an average of 6.5% of their initial body mass (0.6 kg/d) over an average feeding trial of 16 d (initial mass averaged 125 kg). The animals were allowed to eat as much pollock as they wanted but did not increase their food intake to compensate for the low energy they were receiving. The sea lions showed progressive metabolic depression while losing body mass on a pollock-only diet. The loss of body mass while eating pollock was due to the lower gross energy content of pollock versus herring, the higher cost of digesting pollock, and the increased energy loss from digesting the larger quantity of fish needed to compensate for the lower energy content of pollock. Thus, our sea lions would have had to eat 35-80% more pollock than herring to maintain similar net energy intakes. Results from our captive-feeding studies are consistent with the junk-food hypothesis and have serious implications for Steller sea lions that have been eating primarily pollock in the Gulf of Alaska and the Aleutian Islands.

Three-dimensional photogrammetry as a tool for estimating morphometrics and body mass of Steller sea lions (Eumetopias jubatus)

2007 ◽  
Vol 64 (2) ◽  
pp. 296-303 ◽  
Author(s):  
Jason N Waite ◽  
Wendy J Schrader ◽  
Jo-Ann E Mellish ◽  
Markus Horning
Keyword(s):  
Body Mass ◽  
Standard Length ◽  
Three Dimensional ◽  
Body Volume ◽  
Multiple Time ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
3D Photogrammetry ◽  
Measured Mass

A technique was developed to estimate morphometrics and body mass of Steller sea lions (Eumetopias jubatus) using three-dimensional (3D) photogrammetry. 3D photogrammetry reduces many of the problems associated with camera and body position encountered with two-dimensional photogrammetric techniques, allowing body mass estimation of free-ranging, active sea lions, without sedation, heavy weighing equipment, and disturbance. 3D computer wireframes of 53 Steller sea lions of various age classes were generated from multiple time-synchronous digital photos and used to estimate length, girth, and volume. Average estimates of standard length and axillary girth were within ±2.5% and ±4.0% of physically measured dimensions, respectively. Average estimates of standard length and axillary girth using only wireframes based on ideal body postures were within ±1.7% and ±3.1% of physically measured dimensions, respectively. Regressions of physically measured mass on photogrammetrically estimated body volume yielded a predictive model. Body mass estimates using this model were on average within 9.0% (95% confidence interval = ±1.7%) of the physically measured mass. This technique was also successfully applied to reptiles and fish.

Body mass loss and body fluid shifts during dehydration in Dorper sheep

1992 ◽  
Vol 119 (3) ◽  
pp. 419-422 ◽  
Author(s):  
A. A. Degen ◽  
M. Kam
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Body Fluid ◽  
Extracellular Fluid ◽  
Water Volume ◽  
Body Mass Loss ◽  
Fluid Shifts ◽  
Desert Areas ◽  
Dorper Sheep ◽  
Total Body

SUMMARYDorper sheep are raised in extreme desert areas. Body mass loss and body fluid shifts were measured in Dorper rams denied water for 4 days and offered only wheat straw. The rams lost 16·3% body mass, 22·0% total body water volume, 35·1 % extracellular fluid volume and 41·7% plasma volume. On first drinking following dehydration, Dorpers were able to consume 19·7% of their dehydrated body mass and 100·3 % of their body mass loss. It was concluded that Dorpers can survive in harsh deserts through their ability to withstand dehydration and quickly replenish body mass losses when water becomes available.

Brown and white adipose tissue in relation to age and sex in juvenile Richardson's ground squirrels

1983 ◽  
Vol 61 (12) ◽  
pp. 2789-2797 ◽  
Author(s):  
Teresa M. Dolman ◽  
Gail R. Michener
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Body Mass ◽  
White Adipose Tissue ◽  
Ground Squirrels ◽  
Body Lipid ◽  
Specific Mass ◽  
Brown Adipose ◽  
Total Body ◽  
Juvenile Males

Deposits of brown and white adipose tissue were monitored from birth to hibernation in laboratory-born and field-caught juvenile Richardson's ground squirrels (Spermophilus richardsonii). The weight-specific mass of brown adipose tissue was low at birth and, except for a brief increase at 3 days, declined postnatally. Total mass of brown adipose tissue and its lipid content were also low at birth, but increased postnatally, up to hibernation. Brown adipose tissue probably plays a greater role in hibernation thermogenesis than in neonatal thermoregulation. Both total and weight-specific mass of white adipose tissue increased postnatally, with maximum values prior to hibernation. Laboratory-born squirrels were fatter than wild squirrels and acquired more fat for a given increase in body mass. Females, both laboratory-born and wild, were fatter than males, and likewise acquired more fat for a given increase in body mass. Although at entry into hibernation wild juvenile females weighed 20% less than juvenile males, we calculated that females had twice as much total body lipid (91.1 versus 45.8 g).

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