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Social-Ecological Systems Meta-Analysis Database: Studies

Moore, G. J., B. Wienecke, and G. Robertson. 1999. Seasonal change in foraging areas and dive depths of breeding king penguins at Heard Island. Polar Biology 21:376-384.

Abstract:The seasonal variation in the foraging behaviour of king penguins (Aptenodytes patagonicus) was studied at Heard Island (53°05¢S, 73°30¢E) during 1992/ 1993. On seven occasions throughout the breeding cycle, time-depth-light recorders were deployed on breeding adults to record the dive activities and foraging. Foraging locations changed with season: in autumn and spring 1992, adults foraged between 48±52°S and 74±78°E, about 370 km NNE of Heard Island close to the Polar Front. Two penguins tracked in winter travelled 2220 km east of Heard Island (95°E) along the northern ice limit, and 1220 km south of Heard Island to approximately 65°S, respectively. In spring (October), the penguins again for- aged further north than during winter. The foraging area utilised in October overlapped the area where the pen- guins foraged in March/April. The penguins' diving be- haviour also varied seasonally: the modal depth of deep dives (>50 m) increased from about 100 m in February to 220 m in October. Mean dive depths increased from 7052m in March 1992 to 16068m in August 1992. Penguins dived deep (>50 m) only during daylight hours (16 h in February, 9 h in July). Mean dive durations ranged from 2.9 1.1 min in March 1992 to 5.1 1.2 min in August 1992. Associated with changes in foraging location and dive behaviour was a change in diet composition: during summer the penguins ingested mainly myctophid ®sh (>90%) while in winter the most important diet item was squid.

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