Energy requirements for maintenance and growth of captive harbour seals, Phoca vitulina (original) (raw)
Related papers
The effect of feeding on the metabolic rate in harbour seals (Phoca vitulina)
Journal of Comparative Physiology B, 1994
The heat increment of feeding was estimated in harbour seals (Phoca vitulina). Seals were given different amounts of herring, ranging from 0.8 to 2.65 kg. The caloric content of the herring ranged from 6575 to 12560 kJ.kg 1 depending on time of year. Metabolic rate increased within 30 min after feeding, and the magnitude and duration of heat increment of feeding depended on the size of the meal and the caloric content of the herring. Measured heat increment of feeding was up to 14.9% of gross energy intake and metabolic rate increased as much as 46% above resting, postabsorptive metabolic rate for 15 h duration in a harbour seal with a body weight of approximately 40 kg.
Sources of error in estimating food requirements of seals
Polar Record, 1988
Grey seals Halichoerus grypus are common along some parts of the coasts of the North Atlantic Ocean, and many believe they compete with man for common food resources. This also applies to other species of pinnipeds. Sergeant (1973) suggested an estimate of annual weight of food items eaten by the northwest Atlantic population of harp seals Phoca groenlandica, and later food uptake and growth have been studied both in captive ringed seals Phoca hispida (Parsons 1977), harp seals (Keiver and others 1984), grey seals (Ronald and others 1984), and harbor seals Phoca vitulina (Boulva and McLaren 1979). In these studies, however, the animals were either not fed as much as they desired, photoperiod was either not controlled or did not parallel natural changes, and/or the studies lasted only for a short period of time. In the present study we have recorded daily energy intake and growth in a captive grey seal over a period of 3 years under semi-natural light conditions, and exposed important potential sources of error in experimentally estimating energy requirements of northern pinnipeds.
Annual prey consumption by harbor seals (Phoca vitulinaJ
Abstract.-A bioenergetic population model that integrated input on the abundance. distribution, sex- and age-structure, feeding rates. and diet of harbor seals was developed and used to estimate annual,prey con sumption,in the Strait of Georgia during 1988. Owing to recruitment and mortality, the size of the Strait of Georgia population fluctuated sea sonally from a minimum of 12,990 prior 'to the pupping,season,to a maximum of 15,810 following pup ping. The study population repre sented a population,that was,in creasing at an intrinsic rate of 12.5% per annum,and,was,therefore skewed toward younger age-classes. Mean daily per capita gross energy requirements were estimated at 172 watts, of which 30% was lost in fae ces, urine, and the heat increment associated with feeding, 42.3% was expended for basal metabolism, 23.4% for activity, 1.2% for body growth, and 3.2% for reproduction. Mean daily per capita. food require ments were estimated to be 1.9 kg,
Canadian Journal of Zoology-revue Canadienne De Zoologie, 1992
. Metabolic rate and body composition of harbour seals, Phocu vitulina, during starvation and refeeding. Can. J. Zool. 70: 220 -224. The metabolic rate of normally fed harbour seals (Phocu vitulina) was measured during starvation and the subsequent refeeding period. Resting metabolic rate was calculated from the y-intercept of the metabolic rate versus swimming speed curves and was 20% lower during the starvation period than during normal feeding. During starvation, about 50% of mass loss was fat, i.e., 77% of the energy was obtained from fat. Metabolic rate returned to the initial value about 1 week after the onset of refeeding. MARKUSSEN, N. H., RYG, M., et ORITSLAND, N. A. 1992. Metabolic rate and body composition of harbour seals, Phoca vitulina, during starvation and refeeding. Can. J. Zool. 70 : 220 -224. Le taux de metabolisme de Phoques communs (Phoca vitulina) nourris normalement a ete mesure au cours d'un jeQne et au cours de la periode d'alimentation qui a suivi le jeQne. Le taux de metabolisme au repos a ete determine par calcul du point d'intersection avec l'ordonnee de la courbe illustrent le taux de metabolisme versus la vitesse de nage et il s'est avere de 20% plus faible chez les phoques soumis au jeQne que chez les phoques nourris normalement. Au cours du jeQne, environ 50% de la perte de masse etait une perte de graisse, c'est-h-dire que 77% de l'energie venait des graisses. Le taux de metabolisme est revenu h sa valeur initiale 1 semaine aprks la reprise de I'alimentation. [Traduit par la redaction]
Polar Research, 1991
We have employed a model for the energy balance of seals to estimate the energy consumption and energy expenditure of ringed seals throughout the year, using biological and physical parameters as input. Data on growth and seasonal changes in body mass and fat content “drives” the seasonal dynamics of the model output. The energy requirements for lactation and activity are based on data from earlier published studies. The analysis suggests that the food intake of ringed seals is highly seasonal. In adult males it is low during the periods of territory defense, mating and moulting from March to June. During this period the seals lose body mass, mainly as fat. The model predicts that lactating females increase their food intake to some extent during the approximately six-week lactation period. After the ice breakup, food intake increases in both sexes, partly as a result of increasing maintenance energy requirements, and partly because the body fat stores are rebuilt in late summer and autumn. The over-all energy requirements of the ringed seal appear to be basically similar to those of terrestrial mammals.
Seasonal Changes in Food Intake of Harp Seals (Phoca Groenlandica) at 69°N
Marine Mammal Science, 1994
Food intake (PI), body mass (BM), and compartmental growth were recorded for 12 mo in four captive 2–4‐yr‐old male harp seals (Phoca groenlandica), exposed to an artificial light regime that closely resembled natural day length at 69°. In early May before molting, both FZ and BM decreased in all four animals. Total body fat (TBF) declined from 51% of BM in March (n = 4) to 30% in August (n = 2), while total body water (TBW) concomitantly increased from 37% to 51% and total body protein (TBP) from 11% to 17%. In July FI started to increase, while BM started to increase in August. TBF increased while TBW and TBP decreased from August, all three parameters reaching a stable level in October at 47%, 39%, and 12%, respectively. Thereafter, body composition was maintained rather constant until May. Between October and March/April FI fluctuated for all animals, while BM showed a fairly steady increase. Average daily amount of capelin consumed was 2.67 kg·d−1, equivalent to 25,600 kJ·d−1, o...
Causes and consequences of variation in the energy expenditure in grey seals (Halichoerus grypus)
2003
27 2.1 Life history 28 2.2 Diet and foraging behaviour 29 2.3 Assessing seal fisheries interactions .33 CHAPTER 3: METHODS 34 3.1 SMRU captive facility .35 3.2 Animals 35 3.3 Respirometry 3.3.1 Open flow respirometry system 38 3.3.2 Calculation of 02 consumption 42 3.4 Measurement ofbehaviour .43 3.5 Measurement of body composition 45 CHAPTER 4: VARIATIONS IN RESTING METABOLIC RATE 48 4.1 Introduction 19. 4.1.1 Conditions of 'resting' 4.
Seasonal Changes in Energy Requirements of Harp Seals
Journal of Northwest Atlantic Fishery Science, 2010
Seasonal changes in energy intake of northwest Atlantic harp seals were modelled and implemented as a Microsoft Excel ™ spreadsheet. Energy intake of adults during the fourth quarter is almost double estimated intake during the second quarter, with intermediate values during the fi rst and third quarters. Reproduction increases female annual energy requirements by 18%, and adds 4% to the estimated population energy intake. The model was sensitive to changes in metabolizable energy, body mass, and the activity factors selected to estimate cost of activity. Changes in blubber conductivity and body composition had intermediate effects, while changes in water and air temperature and activity had little effect on model output. Comparing annual energy intake between a seasonally varying model and a simplifi ed model (Growth•Activity•Mass 0.75 ) intake estimates were similar if an annual maximum body mass was used. Using minimum estimates of body mass underestimated annual energy intake, but provides more reasonable estimates of energy consumption when seasonal requirements are at a minimum. A simple model adequately describes pinniped gross energy intake. More realistic estimates of gross energy intake would be obtained without increasing model complexity by incorporating seasonal changes in body mass.
2009
Hundreds of stranded harbour seals pups (Phoca vitulina) are brought to wildlife rescue centres every year, often unweaned and in poor body condition. Typical hand-rearing diets include artificial milk-replacers and diets based on macerated fish, both normally fed via gavage. Mortality rates for these animals can be high and weight gains on artificial formulas are low. This study was designed to determine the effect of the following treatments on the growth and survival of captive orphaned seals: (1) feeding pups an artificial milk-replacer versus a fish-based formula; and (2) the provision of supplementary heat. Pups admitted to the facility in summer 2007 (n=145) and 2008 (n=98) were randomly assigned to one of two diets and fed until weaning at roughly 20 days of age. In 2008, 25 pups were also provided with a supplementary heat source. Diet and heat treatments were compared using average daily gain (ADG) and mortality rates. In 2007, with pups fed formulas at 8% of body weight p...
Seasonal energetics of northern phocid seals
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2009
The metabolic rate of harp (Pagophilus groenlandicus), harbor (Phoca vitulina), and ringed seals (Pusa hispida) was measured at various temperatures in air and water to estimate basal metabolic rates (BMRs) in these species. The basal rate and body composition of three harp seals were also measured throughout the year to examine the extent to which they vary seasonally. Marine mammalian carnivores generally have BMRs that are over three times the rates expected from body mass in mammals generally, both as a response to a coldwater distribution and to carnivorous food habits with the basal rates of terrestrial carnivores averaging about 1.8 times the mean of mammals. Phocid seals, however, have basal rates of metabolism that are 30% lower than other marine carnivores. Captive seals undergo profound changes in body mass and food consumption throughout the year, and after accounting for changes in body mass, the lowest rate of food intake occurs in summer. Contrary to earlier observations, harp seals also have lower basal rates during summer than during winter, but the variation in BMR, relative to mass expectations, was not associated with changes in the size of fat deposits. The summer reduction in energy expenditure and food consumption correlated with a reduction in BMR. That is, changes in BMR account for a significant portion of the seasonal variation in energy expenditure in the harp seal. Changes in body mass of harp seals throughout the year were due not only to changes in the size of body fat deposits, but also to changes in lean body mass. These results suggest that bioenergetics models used to predict prey consumption by seals should include timevariant energy requirements.