MEPS 308:303-309 (2006)  -  doi:10.3354/meps308303

Diving behaviour of Mediterranean monk seal pups during lactation and post weaning

M. Gazo1,3,*, C. Lydersen2, A. Aguilar1

1Department of Animal Biology, Faculty of Biology, University of Barcelona, Avgda. Diagonal 645, 08028 Barcelona, Spain
2Norwegian Polar Institute, 9296 Tromsø, Norway
3Present address: Fundació CRAM, Camí Ral 239, 08330 Premià de Mar, Barcelona, Spain

ABSTRACT: Time depth recorders (TDRs) were attached to 3 Mediterranean monk seal pups during a range of periods around weaning, providing a composite picture of activity from the first weeks of life until nutritional independence. The pups entered the water during their first week of life and their diving performance increase progressively with age. All pups spent most of their time at sea (55to 74%), and their swimming activity was greater at nighttime compared with daytime. Dive performance in relation to pup age was poorer compared with other phocid seal species. Dive types were classified using a combination of hierarchical and k-mean clustering. We found 3 dive types: 1 V-shaped and 2 U-shaped. The most common type was U1-dives, mainly used by older pups during 44 to 48% of their total dive time. These dives were relatively deep and long (mean depth = 11.6 ± 9.5m, mean duration = 149.1 ± 80.6 s). They had long bottom times (100 ± 67 s), suggesting that pups were foraging. Pups appeared to start feeding at the end of lactation.

KEY WORDS: Mediterranean monk seal · Diving behaviour · Lactation · Weaning · Monachus monachus

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