Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 499:285-301 (2014) - DOI: https://doi.org/10.3354/meps10660 Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution Christophe Guinet1,*, Jade Vacquié-Garcia1, Baptiste Picard1, Guillaume Bessigneul1, Yves Lebras1, Anne Cécile Dragon1,2, Morgane Viviant1, John P. Y. Arnould3, Frédéric Bailleul1 1Centre d’Etudes Biologiques de Chizé, CNRS, 79360 Villiers en Bois, France 2LOCEAN-UPMC, 4 Place Jussieu, Boite 100, 75252 Paris Cedex 05, France 3School of Life and Environmental Sciences, Faculty of Science & Technology, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia *Corresponding author: guinet@cebc.cnrs.fr ABSTRACT: The distribution of southern elephant seal Mirounga leonina prey encounter events (PEEs) was investigated from the foraging behaviour of 29 post-breeding females simultaneously equipped with a satellite tag, a time-depth recorder and a head-mounted accelerometer. Seal diving depth and PEE were related to water temperature at 200 m (T200), and light level at the surface (L0) and at depth. Approximately half (49%) of all dives were located in waters encompassed between the southern Antarctic Circumpolar Current Front and the Polar Front. Seals dived significantly deeper during the day than at night. Diving and PEE depth increased with increasing T200 and for a given T200 according to L0 and the percentage of surface light reaching 150 m. On average, 540 PEEs per day were recorded. Seals exhibited more PEEs per unit of time spent diving during the twilight period compared with at night, and were least successful during daylight hours. Elephant seals forage in T200 ranging between -1 and 13°C; however, few PEEs were recorded at depths shallower than 400-500 m at night when the T200 exceeded 8°C. The diet of female Kerguelen elephant seals appears to be dominated by myctophids (lanternfish), and according to the average mass of their most likely myctophid prey (9 g, Electrona calsbergi and E. antarctica; 30 g Gymnoscopelus nicholsi and G. piabilis), we estimate that seals consumed 4.8-16.1 kg of fish daily. Despite lower catch rates in warmer waters, no relationship was found between the mean T200 at the scale of the foraging trip and daily or absolute mass gain, suggesting that elephant seals are compensating for lower catch rates by consuming larger/richer prey items in those waters. KEY WORDS: Southern elephant seals · Foraging success · Light · Temperature · Diving behaviour · Prey Full text in pdf format PreviousCite this article as: Guinet C, Vacquié-Garcia J, Picard B, Bessigneul G and others (2014) Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution. Mar Ecol Prog Ser 499:285-301. https://doi.org/10.3354/meps10660 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 499. Online publication date: March 03, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.
Highlights
An increasing number of studies show that, along with the measurement of concomitant oceanographic data, the behaviour of top marine predators can provide valuable insights into the habitat in which they forage (e.g. Biuw et al 2007, 2010)
Sixteen seals were equipped with conductivity− forage mainly in pelagic waters and to a lesser temperature−depth satellite-relay data loggers extent on the Kerguelen and Antarctic continental (CTD-SRDLs, Sea Mammal Research Unit, Univer- shelves combined with either TDR log- Island sub-adult and adult males; Bailleul et al 2010, gers (MK9, Wildlife Computers), set to sample and Dragon et al 2010, Authier et al 2012). As part of this archive pressure, light and temperature levels every work we focused on the pelagic portion of the tracks
The results of the present study clearly demonstrate that during late spring and early summer the diving behaviour and foraging success of SES females were profoundly affected by the physical properties of the water masses visited
Summary
An increasing number of studies show that, along with the measurement of concomitant oceanographic data, the behaviour of top marine predators can provide valuable insights into the habitat in which they forage (e.g. Biuw et al 2007, 2010). (temperature, salinity, light, fluorescence) parameters can be continuously recorded by high-resolution multi-channel data loggers This enables studies of the conditions under which animals live, as well as the ability to monitor their environment (Boehlert et al 2001). Air-breathing diving species such as seals are well-suited for the bio-acquisition (i.e. bio-logging) of movement, behavioural, physiological as well as environmental data using miniaturised animal-attached tags (Rutz & Hays 2009). Their large size allows them to carry electronic devices with minimal disturbance, and researchers can handle them while they are on land in their breeding colonies. Foraging, diving predators have provided new and original information about physical (Charrassin et al 2008, Costa et al 2008, Roquet et al 2009) and biological oceanography (Guinet et al 2013) in often inaccessible regions
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