Swim speed of free-ranging Adélie penguins Pygoscelis adeliae and its relation to the maximum depth of dives |
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| Authors: | Y Ropert-Coudert A Kato K Sato Y Naito J Baudat A Bost Y Le Maho |
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| Institution: | 1National Institute of Polar Research, 1-9-10 Kaga, Itabashi-ku, Tokyo 173-8515, Japan.;
2Centre d'Ecologie et de Physiologie Energétiques, 23 rue Becquerel, F-67087 Strasbourg cedex 2, France. |
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| Abstract: | Swim speed and depth utilization were recorded at a sampling rate of 1 Hz in 14 free-ranging Adélie penguins in Adélie Land, Antarctica during the austral summers of 1996/1997 and 1998/1999. The average swim speeds during the descent, bottom and ascent phases of dives were independent of the maximum depth, while the variability in swim speed decreased with increasing maximum depth, reflecting the physiological constraints of diving. Descent speed, which varied less with maximum depth than speeds measured during other parts of dives, was significantly different among birds. In addition to the speed analysis, a new category of dive profiles with a flat bottom phase and an extremely reduced swim speed is reported. The probable benthic nature of such dives is discussed. |
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