American Journal of Physiology-Legacy Content, 1976
During the antarctic winter emperor penguins (Aptenodytes forsteri) spend up to four mo fasting w... more During the antarctic winter emperor penguins (Aptenodytes forsteri) spend up to four mo fasting while they breed at rookeries 80 km or more from the sea, huddling close together in the cold. This breeding cycle makes exceptional demands on their energy reserves, and we therefore studied their thermoregulation and locomotion. Rates of metabolism were measured in five birds (mean body mass, 23.37 kg) at ambient temperatures ranging from 25 to -47 degrees C. Between 20 and -10 degrees C the metabolic rate (standard metabolic rate (SMR)) remained neraly constant, about 42.9 W. Below -10 degrees C metabolic rate increased lineraly with decreasing ambient temperature and at -47 degrees C it was 70% above the SMR. Mean thermal conductance below -10 degrees C was 1.57 W m-2 degrees C-1. Metabolic rate during treadmill walking increased linearly with increasing speed. Our data suggest that walking 200 km (from the sea to the rookery and back) requires less than 15% of the energy reserves of ...
The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a... more The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by 2H or 3H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both 2HHO and 3HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with 3H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida)...
A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be... more A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be a reliable and reasonably safe immobilisation agent for field work on grey and southern elephant seals. It was better than previously reported drugs used either singly or in combination.
A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be... more A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be a reliable and reasonably safe immobilisation agent for field work on grey and southern elephant seals. It was better than previously reported drugs used either singly or in combination.
A simple one-step procedure that eliminates the need to calibrate the O2 analyzer or measure the ... more A simple one-step procedure that eliminates the need to calibrate the O2 analyzer or measure the flow past the animal is described for calibrating an open-flow respirometry system. The technique is particularly useful for situations of high ambient humidity and for large or active animals where a mask is employed to capture expired gases. A measured N2 flow is used to calibrate the system. The equations describing the technique are given, and the accuracy of the method is discussed in detail. The errors associated with the technique are compared with those of more conventional procedures and are usually smaller.
... (a) R2 Male 9 May 84-13 Aug 84 1 0 63 0-26 RIO Male 18 Jun 85-11 Aug 85 3 0 86 0 37 ... 2. Di... more ... (a) R2 Male 9 May 84-13 Aug 84 1 0 63 0-26 RIO Male 18 Jun 85-11 Aug 85 3 0 86 0 37 ... 2. Diurnal variation in the activity of four male common seals in May, June and July: (a) R2, (b) RIO, (c) R 1I and (d) R25; (El) absent from, (E) diving within or (-) hauled out within study area. ...
In the austral summers of 1986 and 1988–1989, 51 southern elephant seals (Mirounga leonina) at Hu... more In the austral summers of 1986 and 1988–1989, 51 southern elephant seals (Mirounga leonina) at Husvik, South Georgia (54°10′S; 36°43′W), were stomach lavaged after chemical immobilization. Only cephalopod remains were retrieved, including 1070 lower beaks that were identified and measured. In total these were estimated to represent a wet weight of 187.8 kg. Fourteen species of squid from 11 families and 2 species of octopod from 1 family were present. The most important species overall were the squids Psychroteuthis glacialis in terms of numerical abundance (33.7%) and Moroteuthis knipovitchi in terms of estimated biomass (31.2%). The remaining biomass was mainly comprised of the five large muscular squids, Kondakovia longimana (24.0%), P. glacialis (15.4%), Martialia hyadesi (11.2%), Alluroteuthis antarcticus (10.8%), and Gonatus antarcticus (3.6%). Larger seals of both sexes fed on a wider variety of cephalopod species than smaller seals, with large males taking the greatest diver...
Due to the low accessibility of the region, most of the seasonally ice-covered Southern Ocean rem... more Due to the low accessibility of the region, most of the seasonally ice-covered Southern Ocean remains unobserved during winter. Here we show that southern elephant seals (Mirounga leonina), equipped with oceanographic sensors, can measure winter hydrography with unprecedented temporal and spatial resolution. Seals provided a 30-fold increase in hydrographic profiles from the sea ice zone, allowing the major fronts to be mapped south of 60° S. Sea-ice formation rates in the East Antarctic sector were estimated ...
Three types of Argos satellite transmitter were attached to grey seals (Halichoerus grypus) at Do... more Three types of Argos satellite transmitter were attached to grey seals (Halichoerus grypus) at Donna Nook (South Humberside, UK) between 1985 and 1989 in order to investigate their movements. With the first two transmitters (A and B) the entire package was attached to ...
Proceedings of the National Academy of Sciences, 2007
Responses by marine top predators to environmental variability have previously been almost imposs... more Responses by marine top predators to environmental variability have previously been almost impossible to observe directly. By using animal-mounted instruments simultaneously recording movements, diving behavior, and in situ oceanographic properties, we studied the behavioral and physiological responses of southern elephant seals to spatial environmental variability throughout their circumpolar range. Improved body condition of seals in the Atlantic sector was associated with Circumpolar Deep Water upwelling regions within the Antarctic Circumpolar Current, whereas High-Salinity Shelf Waters or temperature/salinity gradients under winter pack ice were important in the Indian and Pacific sectors. Energetic consequences of these variations could help explain recently observed population trends, showing the usefulness of this approach in examining the sensitivity of top predators to global and regional-scale climate variability.
The energetic cost of diving in marine mammals is a difficult value to derive given the problems ... more The energetic cost of diving in marine mammals is a difficult value to derive given the problems of assessing metabolic rate for an animal at sea. Nevertheless, it is fundamental to our understanding of the foraging strategies of air-breathers exploiting underwater food sources. We ...
American Journal of Physiology-Legacy Content, 1976
During the antarctic winter emperor penguins (Aptenodytes forsteri) spend up to four mo fasting w... more During the antarctic winter emperor penguins (Aptenodytes forsteri) spend up to four mo fasting while they breed at rookeries 80 km or more from the sea, huddling close together in the cold. This breeding cycle makes exceptional demands on their energy reserves, and we therefore studied their thermoregulation and locomotion. Rates of metabolism were measured in five birds (mean body mass, 23.37 kg) at ambient temperatures ranging from 25 to -47 degrees C. Between 20 and -10 degrees C the metabolic rate (standard metabolic rate (SMR)) remained neraly constant, about 42.9 W. Below -10 degrees C metabolic rate increased lineraly with decreasing ambient temperature and at -47 degrees C it was 70% above the SMR. Mean thermal conductance below -10 degrees C was 1.57 W m-2 degrees C-1. Metabolic rate during treadmill walking increased linearly with increasing speed. Our data suggest that walking 200 km (from the sea to the rookery and back) requires less than 15% of the energy reserves of ...
The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a... more The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by 2H or 3H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both 2HHO and 3HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with 3H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida)...
A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be... more A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be a reliable and reasonably safe immobilisation agent for field work on grey and southern elephant seals. It was better than previously reported drugs used either singly or in combination.
A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be... more A mixture of ketamine and diazepam, at doses of 6 mg/kg and 0.30 mg/kg respectively, proved to be a reliable and reasonably safe immobilisation agent for field work on grey and southern elephant seals. It was better than previously reported drugs used either singly or in combination.
A simple one-step procedure that eliminates the need to calibrate the O2 analyzer or measure the ... more A simple one-step procedure that eliminates the need to calibrate the O2 analyzer or measure the flow past the animal is described for calibrating an open-flow respirometry system. The technique is particularly useful for situations of high ambient humidity and for large or active animals where a mask is employed to capture expired gases. A measured N2 flow is used to calibrate the system. The equations describing the technique are given, and the accuracy of the method is discussed in detail. The errors associated with the technique are compared with those of more conventional procedures and are usually smaller.
... (a) R2 Male 9 May 84-13 Aug 84 1 0 63 0-26 RIO Male 18 Jun 85-11 Aug 85 3 0 86 0 37 ... 2. Di... more ... (a) R2 Male 9 May 84-13 Aug 84 1 0 63 0-26 RIO Male 18 Jun 85-11 Aug 85 3 0 86 0 37 ... 2. Diurnal variation in the activity of four male common seals in May, June and July: (a) R2, (b) RIO, (c) R 1I and (d) R25; (El) absent from, (E) diving within or (-) hauled out within study area. ...
In the austral summers of 1986 and 1988–1989, 51 southern elephant seals (Mirounga leonina) at Hu... more In the austral summers of 1986 and 1988–1989, 51 southern elephant seals (Mirounga leonina) at Husvik, South Georgia (54°10′S; 36°43′W), were stomach lavaged after chemical immobilization. Only cephalopod remains were retrieved, including 1070 lower beaks that were identified and measured. In total these were estimated to represent a wet weight of 187.8 kg. Fourteen species of squid from 11 families and 2 species of octopod from 1 family were present. The most important species overall were the squids Psychroteuthis glacialis in terms of numerical abundance (33.7%) and Moroteuthis knipovitchi in terms of estimated biomass (31.2%). The remaining biomass was mainly comprised of the five large muscular squids, Kondakovia longimana (24.0%), P. glacialis (15.4%), Martialia hyadesi (11.2%), Alluroteuthis antarcticus (10.8%), and Gonatus antarcticus (3.6%). Larger seals of both sexes fed on a wider variety of cephalopod species than smaller seals, with large males taking the greatest diver...
Due to the low accessibility of the region, most of the seasonally ice-covered Southern Ocean rem... more Due to the low accessibility of the region, most of the seasonally ice-covered Southern Ocean remains unobserved during winter. Here we show that southern elephant seals (Mirounga leonina), equipped with oceanographic sensors, can measure winter hydrography with unprecedented temporal and spatial resolution. Seals provided a 30-fold increase in hydrographic profiles from the sea ice zone, allowing the major fronts to be mapped south of 60° S. Sea-ice formation rates in the East Antarctic sector were estimated ...
Three types of Argos satellite transmitter were attached to grey seals (Halichoerus grypus) at Do... more Three types of Argos satellite transmitter were attached to grey seals (Halichoerus grypus) at Donna Nook (South Humberside, UK) between 1985 and 1989 in order to investigate their movements. With the first two transmitters (A and B) the entire package was attached to ...
Proceedings of the National Academy of Sciences, 2007
Responses by marine top predators to environmental variability have previously been almost imposs... more Responses by marine top predators to environmental variability have previously been almost impossible to observe directly. By using animal-mounted instruments simultaneously recording movements, diving behavior, and in situ oceanographic properties, we studied the behavioral and physiological responses of southern elephant seals to spatial environmental variability throughout their circumpolar range. Improved body condition of seals in the Atlantic sector was associated with Circumpolar Deep Water upwelling regions within the Antarctic Circumpolar Current, whereas High-Salinity Shelf Waters or temperature/salinity gradients under winter pack ice were important in the Indian and Pacific sectors. Energetic consequences of these variations could help explain recently observed population trends, showing the usefulness of this approach in examining the sensitivity of top predators to global and regional-scale climate variability.
The energetic cost of diving in marine mammals is a difficult value to derive given the problems ... more The energetic cost of diving in marine mammals is a difficult value to derive given the problems of assessing metabolic rate for an animal at sea. Nevertheless, it is fundamental to our understanding of the foraging strategies of air-breathers exploiting underwater food sources. We ...
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