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Bathymetry and frontal system interactions influence seasonal foraging movements of lactating subantarctic fur seals from Marion Island
journal contribution
posted on 2009-11-18, 00:00 authored by P de Bruyn, C Tosh, W Oosthuizen, M Bester, John ArnouldJohn ArnouldSixteen lactating subantarctic fur seals Arctocephalus tropicalis were satellite-tracked during the winter of 2006 (n = 6), summer of 2006/07 (n = 6) and autumn/winter (n = 4) of 2007, from Marion Island, Southern Ocean. Despite varied individual movement patterns, a favoured foraging area lay to the northeast of the island. In contrast to findings for populations at similar latitudes, seals from Marion Island did not undertake short overnight foraging trips, but trips consistently went beyond 300 km from the island. This aligns with the at-sea duration of lactating seals’ foraging trips from temperate Amsterdam Island, but differs from subantarctic Crozet and Macquarie islands. Time spent at sea, maximum distances travelled and movement variation of tracks from the island varied seasonally. Faecal analysis suggests the diet comprised primarily myctophid fish with limited seasonal variation. Well-defined areas of restricted movement coincided with significant bathymetric features to the west/northwest of the Crozet Plateau, with the Del Caño Rise clearly being important. Positive and negative sea-surface height anomalies (compared to the mean) appeared to be preferred by most seals across seasons. Higher summer sea-surface temperatures correlated with the movements of some seals. Higher chlorophyll a concentrations dictated transit and foraging areas during summer. Bathymetrically influenced oceanographic variables likely explain these preferred long-distance eastward movements. The Îles Crozet and Marion island subantarctic fur seals differ in their foraging ecology despite being neighbours. Conversely, the subantarctic fur seal populations from the distant Amsterdam and Marion islands appear to be similarly influenced by such environmental factors.
History
Journal
Marine ecology progress seriesVolume
394Pagination
263 - 276Publisher
Inter-ResearchLocation
Oldendorf, GermanyPublisher DOI
ISSN
0171-8630eISSN
1616-1599Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2009, Inter-ResearchUsage metrics
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Keywords
OtariidArctocephalus tropicalisForaging ecologySatellite telemetryOceanographyArea-restricted movementDietDel Caño RiseScience & TechnologyLife Sciences & BiomedicinePhysical SciencesEcologyMarine & Freshwater BiologyEnvironmental Sciences & EcologyDel Cano RisePRINCE-EDWARD ISLANDSSOUTHERN ELEPHANT SEALSARCTOCEPHALUS-GAZELLAOCEANOGRAPHIC FEATURESPHYTOPLANKTON BLOOMATTENDANCE PATTERNSDIVING BEHAVIORCROZET PLATEAUKILLER WHALESORCINUS-ORCAZoologyOceanographyEcology
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