Article

Energy intake and utilisation by nursing bearded seal (Erignathus barbatus) pups from Svalbard, Norway.

Norwegian Polar Institute, Tromsø, Norway.
Journal of Comparative Physiology B (impact factor: 1.97). 02/1996; 166(7):405-11. pp.405-11
Source: PubMed

ABSTRACT In this study we measure energy intake via milk in nursing bearded seal (Erignathus barbatus) pups and determine how this energy is allocated into metabolism and storage of new tissues. This was accomplished using longitudinal mass gain records and the doubly labelled water technique on nursing pups in combination with cross-sectional data on changes in milk composition from bearded seal mothers. The pups (n = 3) were all less than a week old at the start of the experiments. Pups gained 3.3 +/- 0.4 kg.day-1 of which 50% was fat, 14% protein and 36% water. Average daily water influx for the pups was 69.5 +/- 9.0 ml.kg-1. day-1. Average CO2 production during the study period was 0.99 +/- 0.10 ml.g-1.h-1, which corresponds to a field metabolic rate of 642 +/- 67 kJ.kg-1. day-1, or 6.0 +/- 0.5 times the predicted basal metabolic rate according to Kleiber (1975). The pups drank an average of 7.6 +/- 0.5 kg of milk daily. This corresponds to a daily energy intake of 154 +/- 8 MJ, 47 +/- 14% of which was stored as new body tissue. Despite this high energy intake bearded seal pups do not get as fat as do other nursing phocids. This is in part due to their larger body size but also due to their very active aquatic lifestyle and the lower and more consistent fat content of the milk compared to other phocid species. Bearded seal mothers forage during lactation and may also be involved in teaching their pups to feed independently. All these data suggest that the lactation strategy of bearded seals differs from the phocid norm.

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Keywords

active aquatic lifestyle
 
Average CO2 production
 
bearded seal mothers
 
Bearded seal mothers forage
 
cross-sectional data
 
doubly labelled water technique
 
energy intake
 
energy intake bearded seal pups
 
field metabolic rate
 
lactation strategy
 
larger body size
 
longitudinal mass gain records
 
milk composition
 
nursing bearded seal
 
nursing phocids
 
nursing pups
 
phocid norm
 
phocid species
 
predicted basal metabolic rate
 
week old
 

C Lydersen