Sex-specific variation in the use of vertical habitat by a resident Antarctic top predator

Theoni Photopoulou*, Karine Heerah, Jennifer Pohle, Lars Boehme

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Patterns of habitat use are commonly studied in horizontal space, but this does not capture the four-dimensional nature of ocean habitats (space, depth, and time). Deep-diving marine animals encounter varying oceanographic conditions, particularly at the poles, where there is strong seasonal variation in vertical ocean structuring. This dimension of space use is hidden if we only consider horizontal movement. To identify different diving behaviours and usage patterns of vertically distributed habitat, we use hidden Markov models fitted to telemetry data from an air-breathing top predator, the Weddell seal, in the Weddell Sea, Antarctica. We present evidence of overlapping use of high-density, continental shelf water masses by both sexes, as well as important differences in their preferences for oceanographic conditions. Males spend more time in the unique high-salinity shelf water masses found at depth, while females also venture off the continental shelf and visit warmer, shallower water masses. Both sexes exhibit a diurnal pattern in diving behaviour (deep in the day, shallow at night) that persists from austral autumn into winter. The differences in habitat use in this resident, sexually monomorphic Antarctic top predator suggest a different set of needs and constraints operating at the intraspecific level, not driven by body size.
Original languageEnglish
Article number20201447
Number of pages10
JournalProceedings of the Royal Society B: Biological Sciences
Volume287
Issue number1937
Early online date21 Oct 2020
DOIs
Publication statusPublished - 28 Oct 2020

Keywords

  • Diving behaviour
  • Water mass
  • Continental shelf
  • Weddell seal
  • Sex-specific variation
  • Hidden Markov model

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