Seasonal variation in the metabolic rate of harp seals: unexpected energetic economy in the cold ocean

1994 ◽  
Vol 72 (9) ◽  
pp. 1625-1632 ◽  
Author(s):  
Deane Renouf ◽  
Rosemary Gales

The metabolic rate of nine harp seals was measured chronically over a 12-month period using indirect calorimetry. The extent to which the seals' oxygen consumption was predicted by the allometric equation relating basal metabolic rate to body mass depended upon how the former was operationally defined and on the breeding status, sex, and age of the animal. There were large seasonal changes in the oxygen consumption of adult males and reproductive females when metabolic rate was defined as the lowest hourly mean [Formula: see text] in, typically, 23 h of measurement. From April until August, the males' metabolic rate averaged as much as 83% higher than the allometric prediction from body mass, but for the rest of the year their oxygen consumption was not different from the expected value for mammals. Pregnant and pseudopregnant females showed a brief spring elevation in metabolic rate, but otherwise their oxygen consumption was well below that predicted by allometry. In one female who spontaneously aborted some 7 months after insemination, [Formula: see text] increased to the value for mammals shortly thereafter, to a level resembling that of the only female who was not pregnant and who showed no seasonal variation in oxygen consumption. The immature seals' records are highly variable, showing no clear intra-annual pattern; however, their metabolic rates were lower than expected for young mammals. All seasonal shifts were in the opposite direction to the large changes in body mass exhibited by these seals. The effect of these findings in reducing the calculated impact of harp seals on the North West Atlantic fishery is discussed.

2003 ◽  
Vol 51 (6) ◽  
pp. 603 ◽  
Author(s):  
M. P. Ikonomopoulou ◽  
R. W. Rose

We investigated the metabolic rate, thermoneutral zone and thermal conductance of the eastern barred bandicoot in Tasmania. Five adult eastern barred bandicoots (two males, three non-reproductive females) were tested at temperatures of 3, 10, 15, 20, 25, 30, 35 and 40°C. The thermoneutral zone was calculated from oxygen consumption and body temperature, measured during the daytime: their normal resting phase. It was found that the thermoneutral zone lies between 25°C and 30°C, with a minimum metabolic rate of 0.51 mL g–1 h–1 and body temperature of 35.8°C. At cooler ambient temperatures (3–20°C) the body temperature decreased to approximately 34.0°C while the metabolic rate increased from 0.7 to 1.3 mL g–1�h–1. At high temperatures (35°C and 40°C) both body temperature (36.9–38.7°C) and metabolic rate (1.0–1.5 mL g–1 h–1) rose. Thermal conductance was low below an ambient temperature of 30°C but increased significantly at higher temperatures. The low thermal conductance (due, in part, to good insulation, a reduced body temperature at lower ambient temperatures, combined with a relatively high metabolic rate) suggests that this species is well adapted to cooler environments but it could not thermoregulate easily at temperatures above 30°C.


1990 ◽  
Vol 68 (3) ◽  
pp. 470-475 ◽  
Author(s):  
Morten Ryg ◽  
Thomas G. Smith ◽  
Nils Are Øritsland

Seasonal changes in body mass and body composition of ringed seals (Phoca hispida) from the Svalbard Islands are described. The blubber content of adult females decreased from a high of about 50% at the beginning of the pupping season in March–April to a low of 31% during moulting in June. In adult males, the blubber content decreased from 41% in March to 29% in June. By estimating an individual seal's body mass by 1 April from its standard body length, we calculated an average daily loss of body mass of 160 g/day in adult females and 100 g/day in adult males from the start of lactation to the middle of moulting. The blubber content of sexually immature seals was less in June and July than in April, but the seasonal changes were smaller than in adult seals. We found no evidence of significant changes in core mass in adult seals, and suggest that the seasonal body mass changes are mostly due to changes in body fat content.


2022 ◽  
Author(s):  
Paul Pop ◽  
Kuldeep Singh Barwal ◽  
Randeep Singh ◽  
Puneet Pandey ◽  
Harminder Pal Singh ◽  
...  

Vagrans egista sinha (Kollar, [1844]), the Himalayan Vagrant is a subspecies of Nymphalid (Brush-footed) butterflies spread across Asia, whose western limit is in the north-west India. Observations of this subspecies have considerably increased over the past half-a-decade, with a spike in new sightings to the west of their previously known range. This has been considered as a range extension. The current study reports new records of this species from Bilaspur District, Himachal Pradesh, India (which are the first records for the district), through systematic and opportunistic sampling. This raises the question of whether the purported range extension towards the west could instead be a range shift or vagrancy, and whether there is any shift in elevational ranges in the populations across their known range. Questions pertaining to spatial differences in elevational ranges and seasonal variation, across their range, also piqued our curiosity. Using data from academic sources (such as published literature and museum collections), supplemented by data from public participation in scientific research and personal observations, these research questions are addressed. The accuracy of results when using citizen science data is also explored using the same dataset, focused on the impact of method of extraction of coordinates, and elevation derived from it under different scenarios. It was discovered that there has not been a range shift (either longitudinal or latitudinal) and observations do not suggest vagrancy but a case of range extension. Other results indicated that there was no climb of population to higher elevations, no spatial differences in elevational ranges in the populations, or seasonal variation in activities across their range. It was also discovered that the method of data collection by, and extraction from, citizen science databases, can influence the accuracy of the results. Some problems involved in collecting data are discussed, and remedial solutions are suggested.


1997 ◽  
Vol 75 (11) ◽  
pp. 1781-1789 ◽  
Author(s):  
Patrice Boily ◽  
David M. Lavigne

Resting metabolic rate (RMR) data obtained from five juvenile and three adult female grey seals (Halichoerus grypus) in captivity over a period of 3.5 years were examined for developmental and seasonal changes. Three juveniles exhibited a significant relationship between log10 RMR and log10 mass, with individual slopes ranging from 0.42 to 1.62. Two of these exhibited a significant relationship between log10 RMR and log10 age. The remaining two juveniles and the three adults exhibited no significant relationship between RMR and body mass. With increasing size and age, RMRs of juveniles approached predicted values for adult mammals, but the large variation made it difficult to establish the precise age at which they achieved an adult-like RMR. RMRs of adults and juveniles exhibited marked seasonal changes. In juveniles, seasonal changes in RMR were limited to the annual moult, when the average RMR was 35% higher than during the rest of the year. In adults, changes in RMR were not limited to the time of the annual moult; rather, RMR was lower (by up to 50%) in the summer than during other seasons.


1993 ◽  
Vol 71 (5) ◽  
pp. 1041-1045 ◽  
Author(s):  
Lyn C. Branch

Activity patterns of adult male, adult female, and immature plains vizcacha (Lagostomus maximus) were compared throughout the year, and seasonal changes in body mass were documented for adults. All sex–age classes spent more time feeding in winter and less time at the den site (vizcachera) than in other seasons. The pattern was reversed for summer. Seasonal changes in activity budgets for males were associated with an increase in male–male conflicts and territorial displays at the vizcachera. Body mass of males declined in summer, when they were competing for access to areas used by females, and reached a minimum during the fall breeding season. Females spent less time foraging and more time at the den site after parturition in spring. Body mass of females did not change significantly with season. Throughout the year, activity patterns were similar for females and immatures. During all seasons, adult males spent less time foraging and more time at the vizcachera than other sex–age classes did. From a variety of observations, I suggest that the costs of reproduction, including mass loss, shorter feeding time, and short tenure in a social group, are high for male vizcachas.


1998 ◽  
Vol 76 (8) ◽  
pp. 1520-1528 ◽  
Author(s):  
D A Rosen ◽  
D Renouf

This study tested the hypothesis that seasonal variation in resting metabolic rate (RMR) was more closely related to changes in total energy use than to energy intake. It also quantified the extent to which variation in metabolism contributed to changes in total energy expenditure. RMR, gross energy intake, and body mass and composition were measured in six captive Atlantic harbour seals (Phoca vitulina concolor) over 16 months. Gross energy intake during the year (across all seals) averaged 25.4 ± 4.1 MJ/d (mean ± SD). The energy used by the seals Eused a composite measure of energy expenditure from ingested energy and tissue catabolism) averaged 19.2 ± 3.4 MJ/d. RMR averaged 11.2 ± 1.5 MJ/d during the year, while mass-corrected metabolism declined with age. The seals displayed significant changes in both absolute and mass-corrected metabolism during the year. Overall, Eused was a stronger predictor of changes in metabolism than either gross energy intake or body mass. Mass-corrected metabolic rate was more closely related to Eused than was absolute metabolism. Energy changes in metabolism during the year (range = 6.9 ± 1.9 MJ/d) were minor compared with those in Eused (27.8 ± 7.3 MJ/d). These results suggest that seasonal changes in metabolism were a response to, or facilitated by, concurrent changes in Eused but were not the cause of variation in Eused. Rather, variation in both RMR and Eused was the result of changes in other bioenergetic components of the seals' energy budget, such as activity.


2000 ◽  
Vol 48 (3) ◽  
pp. 241 ◽  
Author(s):  
P. C. Withers ◽  
G. G. Thompson ◽  
R. S. Seymour

We studied the thermal and metabolic physiology of a single specimen of the north-western marsupial mole, Notoryctes caurinus, an almost completely fossorial Australian marsupial, and compared it with the morphologically convergent Namib desert golden mole, Eremitalpa granti namibensis. This was the first study of any aspect of the physiology of this rare marsupial. Mean body mass of the marsupial mole was 34 g. Body temperature (Tb) was low and labile, ranging from 22.7 to 30.8˚C over a range of ambient temperature (Ta) from 15 to 30˚C. The highest Tb of 30.8˚C was significantly lower than expected for a marsupial of this body mass. Metabolic rate varied with Ta in an attenuated fashion for an endotherm, because of the labile Tb. Basal metabolic rate (BMR) was 0.63 mL O2 g–1 h–1, at a Ta of 30˚C. This was lower than expected for a 34-g marsupial, but was not different from expected for a marsupial when corrected to a Tb of 35˚C (0.94 mL O2 g–1 h–1). Evaporative water loss increased from 0.8 mg g–1 h–1 at 15˚C to 3.7 at 30˚C. Wet thermal conductance was 0.2 mL O2 g–1 h–1 ˚C–1 at 15˚C and 0.6 at 25˚C; these values were higher than expected for a marsupial. The net metabolic cost of transport (NCOT) for running (0.0022 mL O2 g–1 m–1 at a mean velocity of 484 m h–1) was similar to expected values for walking and running mammals. The NCOT for sand-swimming (0.124 mL O2 g–1 m–1 at a mean velocity of 7.6 m h–1) was substantially higher, and at a much lower velocity than for running, but was similar to NCOT for sand-swimming by the Namib golden mole. We conclude that the marsupial mole differs in some aspects of thermal and metabolic physiology from other marsupials, most likely reflecting its almost completely fossorial existence.


2011 ◽  
Vol 43 (6) ◽  
pp. 733-749 ◽  
Author(s):  
MONIKA KRZYŻANOWSKA ◽  
C. G. NICHOLAS MASCIE-TAYLOR

SummaryUsing a sample of 2090 father and son pairs, the regional variation in height, weight and body mass index (BMI) with intra- and inter-generational migration within Britain was examined. Highly significant regional differences in means were found only for fathers. The overall mean height difference between regions ranged from about 2.7 cm to 3.1 cm, with the tallest fathers being found in the East & South-East region and the shortest in Wales. The variation in mean weight between regions was less significant, with the difference between the heaviest region (West Midlands) and lightest (South-West) being about 3.5 kg. For BMI the highest mean was in the North and Wales and the lowest in the South-West (difference of about 1 kg m−2). Intra-generational migrants were, on average, significantly taller than non-migrants for both fathers (+1.4 cm) and sons (+2 cm), but BMI was only significant in fathers, with migrant fathers, on average, having a lower BMI. There were no significant differences in weight between geographically mobile groups for either fathers or sons. Differentiating between regional in- and out-migration revealed that in the fathers' generation in-migrants were taller, on average, in six of the nine regions. The tallest in-migrants among fathers came into the North region; the tallest out-migrants were from Yorkshire & Humberside and the shortest were from Scotland. The largest positive gain on fathers' height was in the West Midlands region and Scotland, while negative effects were found in the Yorkshire & Humberside, East Midlands and East & South-East regions. For sons in-migrants were taller in all regions except Wales, with the largest differences between in-migrants and non-migrants being in the South-East and South-West. For out-migrants, the tallest sons came from Wales, while the shortest came from the East Midlands region. The North, East Midlands, East & South-East and West Midlands regions were net gainers, while Wales and Scotland were net losers. For BMI among fathers, in-migrants were of lower BMI than non-migrants. For out-migrant fathers, the North-West and South-West regions were the only two regions showing positive values, with the largest negative values being found in the East Midlands and Yorkshire & Humberside. The net effect of migration indicated that the largest gains were in the East Midlands and Yorkshire & Humberside regions and the largest losses were in Scotland and Wales. The inter-generational migration for BMI showed that in-migrating sons into the North-West and Wales had higher BMI than sedentes, while in-migrants into Yorkshire & Humberside were lower in BMI. In all regions out-migrants had lower BMI than non-migrants. The net effect of migration revealed that six of the nine regions were net gainers, while the Yorkshire & Humberside region was a net loser.


2012 ◽  
Vol 87 (4) ◽  
pp. 501-509 ◽  
Author(s):  
J. Brown ◽  
P. Brickle ◽  
B.E. Scott

AbstractThe parasite fauna of juvenile Dissostichus eleginoides, while they inhabit the Falkland's shelf, was examined, giving new detailed information on spatial, ontogenic and seasonal variations. A total of 24,943 parasites from 15 different taxa were found in the stomach of 502 individual fish. Parasite species composition and abundance allowed separation of toothfish by area between the north-west and south-east of the Falklands. The digenean, Elytrophalloides oatesi, and the nematodes, Hysterothylacium spp. and Anisakis spp., were the most common, all with a prevalence >20%. For some seasons ontogenic changes in abundance were significant in these three parasite taxa, and this is discussed in terms of ontogenic and seasonal changes in diet. Elytrophalloides oatesi and Hysterothylacium spp. showed spatial and seasonal differences in abundance with greater numbers in the warmer waters of the north-west and during the summer months. Differences in abundance of E. oatesi between the Falklands and other regions indicate its potential for use as a biological tag to study toothfish movements and population structure; however, more seasonal data would be required before this technique could be used.


Sign in / Sign up

Export Citation Format

Share Document