MEPS

Marine Ecology Progress Series

MEPS is a leading hybrid research journal on all aspects of marine, coastal and estuarine ecology. Priority is given to outstanding research that advances our ecological understanding.

Online: ISSN 1616-1599

Print: ISSN 0171-8630

DOI: https://doi.org/10.3354/meps

Impact Factor2.1 (JCR 2025 release)

Article Acceptance Rate52.2% (2024)

Average Time in Review216 days (2024)

Total Annual Downloads2.917.093 (2025)

Volume contents
Mar Ecol Prog Ser 378:299-308 (2009)

Diverse foraging strategies in lactating New Zealand sea lions

ABSTRACT: Diving and foraging behaviours of marine predators are thought to be coupled with species demographics, with benthic foraging species found to have small population sizes and low growth rates. This was thought to be the case for New Zealand (NZ) sea lions Phocarctos hookeri, previously identified as solely benthic foragers with a small declining population. Female NZ sea lions dive deeper and for longer than any other otariids (eared seals). They exceed their calculated aerobic dive limits (cADL) during 68% of all dives, indicating that they are operating near their maximum physiological capacity. Recently, however, individual NZ sea lions have been found to have 2 distinct dive profile types or foraging patterns: a benthic diving profile and a deeper, more varied meso-pelagic diving profile. The ecological significance and implications of individual foraging specialisation in otariids have had limited attention in the past. Here, we compared the foraging behaviour of female NZ sea lions that use these 2 distinct dive profiles and discuss how the 2 foraging patterns may indicate differing prey choice, as well as their possible implications for individual reproductive ability and interactions with fisheries and, therefore, species demographics. Our ultimate goal is to understand the causes of this individual foraging specialisation and to incorporate such variation when determining management options for this threatened, declining species.

KEYWORDS

B. Louise Chilvers (Co-author)

  • Marine Conservation Unit, Department of Conservation, PO Box 10420, Wellington 6143, New Zealand

Ian S. Wilkinson (Co-author)

  • Marine Conservation Unit, Department of Conservation, PO Box 10420, Wellington 6143, New Zealand
  • Department of Environment and Conservation, Locked Bag 914, Coffs Harbour, New South Wales 2450, Australia