Winter use of sea ice and ocean water mass habitat by southern elephant seals: The length and breadth of the mystery

Abstract

Winter use of sea ice and ocean water-mass habitat by southern elephant seals: The length and breadth of the mystery, Progress in Oceanography (2015), doi: http://dx.doi.org/ 10. 1016/j.pocean.2015.05.023 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights 20• Time-series of 35 elephant seal winter foraging trips to Antarctica were analysed 21• A high resolution dive behaviour dataset was used to predict foraging events 22• The links between foraging and sea ice, hydrography and topography were quantified 23• Foraging strategies depended on the sex of seals 24• The foraging activity was associated with a number of oceanographic discontinuities 25

Under the sea ice: Exploring the relationship between sea ice and the foraging behaviour of southern elephant seals in East Antarctica

“…This study follows on from previous work on Kerguelen SESs during winter, showing that adult females were closely associated within the marginal sea ice zone, following the northward sea ice extension, and foraging in highly concentrated sea ice close to the sea ice edge Hindell et al, 2016;Labrousse et al, 2015). In contrast, it was shown that sub-adult males remained deep within the sea ice foraging mainly over the Antarctic shelf or within the Antarctic Slope Front (ASF) in sea ice of intermediate concentration.…”

“…For these individuals, the section of tracks where animals travelled again south within the sea ice region (one female and two males) after their return to the colony were removed from analysis. Details of the instrumentation, seal handling and data processing for filtering ARGOS positions are provided by Labrousse et al (2015). An average of 18.1 ± 8.6 tag positions were transmitted via the ARGOS system each day.…”

“…Although considered to be "non sea ice obligate", some SESs interact strongly with the sea ice environment during their long annual migrations from their breeding colonies on sub-Antarctic islands to their high-latitude foraging grounds (Bornemann et al, 2000;Bailleul et al, 2007;Biuw et al, 2010;Hindell et al, 2016;Labrousse et al, 2015). Importantly for this study, there are two foraging strategies during the post-moult foraging trips of SESs from Kerguelen Islands; some individuals use the Kerguelen shelf or frontal regions of the Antarctic Circumpolar Current (ACC), while others travel south within sea ice covered areas to reach the periAntarctic shelf (Bailleul et al, 2010).…”

“…Moreover, as deep-diving, wide-ranging mesopredators (Hindell et al,1991a(Hindell et al, , 1991bMcConnell et al, 1992) and major consumers of marine resources of the Southern Ocean (Guinet et al 1996, SESs depend upon an extensive set of trophic levels within the marine food web and their foraging and breeding performances reflect ecosystem status (Trathan et al, 2007). They also utilize different marine habitats depending on their sex (Bailleul et al, 2010;Labrousse et al, 2015) and breeding colony location (Biuw et al, 2007;Hindell et al, 2016). Among the main populations located in the South Atlantic, Southern Indian and South Pacific Oceans, contrasting demographic trends are observed, presumably in response to environmental variability (McMahon et al, 2005;Hindell et al, 2016).…”

“…The pattern of males diving in waters with low sea ice concentration while on the Antarctic shelf could be explained by either an early arrival in the season in the Antarctic region, movements restricted to sectors where sea ice extent is low, or potentially by use of coastal polynyas Hindell et al, 2016;Labrousse et al, 2015). This study builds upon this previous work by investigating sea ice habitat use using both sea ice concentration and for the first time the spatio-temporal variability of sea ice around the seals' position using a long (i.e.…”