Antarctic Science

Biological Sciences

Post-breeding at-sea movements of three central-place foragers in relation to submesoscale fronts in the Southern Ocean around Bouvetøya

Andrew D. Lowthera1 c1, Christian Lydersena1, Martin Biuwa1a2, P.J. Nico de Bruyna3, Greg J.G. Hofmeyra4 and Kit M. Kovacsa1

a1 Norwegian Polar Institute, Fram Centre, N-9296 Tromsø, Norway

a2 Aquaplan-niva, Fram Centre, N-9296 Tromsø, Norway

a3 Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa

a4 Port Elizabeth Museum at Bayworld, Humewood 6013, Port Elizabeth, South Africa

Abstract

At-sea behaviour of central-place foraging fur seals and penguins in the Southern Ocean is understudied during the latter stages of parental care and the subsequent pre-moulting period. This biologically important period is costly to investigate due to the risk (or certainty) of losing tracking instruments when the animals moult. Early in this period, parents must meet the increasing demands of larger, more mobile offspring that are still nutritionally dependent and then the parents must recover lost body condition prior to the onset of their annual moult. This study reports late-season, at-sea movement patterns of macaroni penguins, chinstrap penguins and adult female Antarctic fur seals from the subantarctic island Bouvetøya, in relation to remotely-sensed oceanographic features. Foraging trips differing significantly in direction and distance travelled compared to those performed earlier in the breeding season, coincide with the time when offspring would be expected to become independent. On these trips, macaroni penguins moved towards the Polar Front while chinstrap penguins and Antarctic fur seals moved southward. Individuals from all three species appeared to target submesoscale ocean features once they were presumed to have been released from the constraints of feeding their young and were able to travel greater distances from the colony.

(Received August 20 2013)

(Accepted March 07 2014)

(Online publication May 29 2014)

Key words

  • foraging ecology;
  • fur seals;
  • hidden Markov models;
  • oceanography;
  • penguins;
  • telemetry
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