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Foraging site fidelity of lactating New Zealand sea lions

Authors


  • Editor: Andrew Kitchener

Correspondence:
B. Louise Chilvers, Marine Conservation Unit, Department of Conservation, PO Box 10420, Wellington 6143, New Zealand. Tel: +64 4 471 3073; Fax: +64 4 471 1082
Email: lchilvers@doc.govt.nz

Abstract

Ecologists often describe the foraging ecology of a species as a whole, treating conspecific individuals as ecologically equal. However, individual specialization has potentially important ecological, evolutionary and conservation implications. Foraging studies are usually based on the foraging behaviours of individuals sampled in only 1 year. In this study, the site fidelity of foraging locations of nine female New Zealand sea lions (NZ sea lions Phocarctos hookeri) from Enderby Island, Auckland Islands, were investigated by repeating their satellite tracking between 1 and 4 years after they were first tracked. Females were monitored during early lactation in the austral summers of 2001–2005. The kernel ranges of females' foraging satellite location concentrations overlapped consistently within and between years. As predicted for benthic foragers, NZ sea lions show low individual variability in foraging behaviour and greater specialization. It is important to understand the spatial and temporal limitations on an individual's foraging-site fidelity, because they can affect a species' ability to cope with environmental changes and anthropogenic impacts. This has significant implications for NZ sea lions management and conservation.

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