Lactation in the Ringed Seal ( Phoca hispida )

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Hammill, M. O., Lydersen, C., Ryg, M., Smith, T. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1991
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Phoca hispida; ringed seal
• Online Access: http://dx.doi.org/10.1139/f91-288; http://www.nrcresearchpress.com/doi/pdf/10.1139/f91-288

Length of lactation, pup growth rate, and female weight loss in ringed seals (Phoca hispida) were estimated using cross-sectional data from the Canadian and Norwegian Arctic. At birth the pups had a standard length of 63.4 cm (SE = 1.3, N = 11) and weighed 5.4 kg (SE = 0.4, N = 6). Weaning occurred approximately 39 d (range 36–41 d) after birth at an estimated length of 88.4 cm (SE = 0.65, N = 96) and an estimated weight of 22.1 kg, resulting in an increase in length of 0.64 cm∙d −1 and a weight change of 0.43 kg∙d −1 . Regression of female weight on the number of days after the nominal date of birth for each region indicated that the postpartum female weighed 81.2 kg and lost 0.64 kg∙d −1 (95% CI = ±0.20). During lactation, female weight declined by an estimated 32%, with much of the loss occurring from the blubber. Analyses of stomachs indicated that ringed seals supplemented stored energy reserves by feeding during lactation.