Vitenskapelig artikkel

Diving behaviour of lactating bearded seals (Erignathus barbatus) in the Svalbard area

Krafft, Bjørn Arne; Lydersen, Christian; Kovacs, Kit; Gjertz, Ian; Haug, Tore

Publikasjonsdetaljer

Tidsskrift: Canadian Journal of Zoology, vol. 78, p. 1408–1418, 2000

Utgave: 8

Internasjonale standardnumre:
Trykt: 0008-4301
Elektronisk: 1480-3283

Open Access: none

Lenker:
DOI

This study documents activity patterns and diving behaviour of four bearded seal (Erignathus barbatus) mothers during the lactation period. The females spent 8 +/- 3% (mean +/- SD) of their time hauled out on the ice and 92 +/- 3% in the water. Approximately half of their time was spent diving. During the study 15 077 dives were recorded. The duration of dives was 2.0 +/- 2.3 min and diving depth was 17.2 +/- 22.5 m (maximum 18.7 min and 288 m, respectively). Haulout periods occurred 3 +/- 2 times per day (duration = 44.0 +/- 98.1 min). The overall distance swum per day was 48.1 +/- 23.2 km. Three dive types were differentiated using a combination of hierarchical and k-means clustering, one V-shaped grouping and two U-shaped groupings. The most common dive type was U(1); these dives were the deepest and longest type (depth = 28 +/- 32 m, duration = 185 +/- 146 s), and bottom time occupied a significant fraction of the total dive time (120 +/- 120 s). These dives are likely foraging dives. Lactation is energetically demanding for bearded seals, and females do forage while they have dependent pups.