Diving behaviour of sub-adult harbour seals (Phoca vitulina) at Prins Karls Forland, Svalbard

• Published in: Polar biology 2002-03, Vol.25 (3), p.230-234
• Main Authors: KRAFFT, Bjørn A, LYDERSEN, Christian, GJERTZ, Ian, KOVACS, Kit M
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal behavior; Animal ethology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Depth recorders; Diving; Foraging behavior; Fundamental and applied biological sciences. Psychology; Harbors; Mammalia; Marine; Marine biology; Marine mammals; Phoca vitulina; Psychology. Psychoanalysis. Psychiatry; Vertebrata
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-001-0330-2

Diving behaviour of sub-adult harbour seals (Phoca vitulina) from Svalbard was studied using time-depth recorders (n=3), during the post-moulting period. The seals spent 82±10% of their time in the water and 18±10% of their time hauled out during the autumn study period. Activity patterns were significantly affected by both tidal and light cycles. Most of the dives (n=11,322) were relatively shallow (mean depth 40.6±25.5 m) and of short duration (mean duration 2.6±1.0 min) with maximum depth and duration values of 172 m and 10 min, respectively. The dives were classified into one V- and two U-shaped classes, via PCA and cluster analyses. The most frequent dive type, U^sub 1^-dives, were much deeper, lasted longer, and had longer bottom time and faster ascent and descent rates than the other dive types. Approximately 70% of all dives fell into this category and these dives occurred predominantly in clearly defined bouts. Diving bouts lasted 12.5 h on average and consisted almost entirely of U^sub 1^-dives (97.5%). Harbour-seal foraging in Svalbard, at least that which is performed by juveniles during the autumn, appears to involve dedicated excursions that include very intense diving bouts.[PUBLICATION ABSTRACT]