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Temporal patterns of milk production in Antarctic fur seals (Arctocephalus gazella)

journal contribution
posted on 1995-09-01, 00:00 authored by John ArnouldJohn Arnould, I L Boyd
The timing of milk production in Antarctic fur seals was studied at Bird Island, South Georgia. Like all lactating otariid seals (Pinnipedia: Otariidae), Antarctic fur seal females alternate between short nursing periods ashore and regular foraging trips to sea. Females do not necessarily return to the colony with full mammae, which indicates that mammary volume capacity is unlikely to limit foraging trip duration. Upon arrival at the colony, milk fat (r 2 = 0.33, P < 0.04) and protein (r 2 = 0.60, P < 0.002) content were positively correlated to the time spent at sea. A similar trend was observed in the milk produced on land. The rate of milk energy production was much lower at sea (5.02 ± 0.05 MJ day ‐1 ) than on land (23.66 ± 4.4 MJ ‐1 day ‐1 ). The rate of milk energy production during the foraging trip was negatively correlated to the time spent at sea (r 2 = 0.29, P < 0.05), whereas the rate of milk energy production on land was positively correlated (r 2 = 0.61, P < 0.001) to the duration of the preceding foraging trip. The total amount of milk energy delivered to the pup during each twoday nursing period was positively correlated (r 2 = 0.60, P < 0.002) to the duration of the previous foraging trip. The overall rate of milk energy delivery, however, was independent of foraging trip duration. This accords with previous observations that the growth rates of Antarctic fur seal pups are unaffected by maternal foraging trip duration patterns.

History

Journal

Journal of zoology

Volume

237

Issue

1

Pagination

1 - 12

Publisher

Blackwell Publishing

Location

Hoboken, N.J.

ISSN

0952-8369

eISSN

1469-7998

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1995, Zoological Society of London