Occurrences and activities of New Zealand sea lions Phocarctos hookeri at non-natal Macquarie Island (1965–1980)

ABSTRACT

The distribution of New Zealand sea lions is typically localised to New Zealand and its remote subantarctic islands. However, non-resident male sea lions were seen on Macquarie Island, 650 km from their nearest natal islands, in all months of all years from 1965 to 1980. The majority of the apparently opportunistic sightings were at the northern end of the island. Sightings increased from May to a September-October peak that was coincident with the cessation of breeding activities in the sea lions’ natal range and the period when resident gentoo and royal penguins, and fur and elephant seals aggregated for breeding, all of which are now confirmed prey for New Zealand sea lions on Macquarie Island. The long-term effect of predation pressure from New Zealand sea lions on resident species remains unmeasured. After sleeping, interacting with southern elephant seals was a core sea lion activity. Predation on seabirds and interactions with elephant seals increase the risk of cross-species disease transmission.

KEYWORDS:

• Amensalism
• endemic
• migrant
• predation
• disease‌

Acknowledgements

This account of Hooker’s sea lions was made possible by the individual who had the insight to collate sightings made by members of the ANARE on Macquarie Island between 1965 and 1980. My thanks to the reviewers.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data and metadata used in this study are available from the Australian Antarctic Data Centre via the following link: https://data.aad.gov.au/metadata/AAS_2265_Hookers_sea_lions.

Ethics statement

This was a desktop study based on a log of marine mammal sightings collected on Macquarie Island between 1965 and 1980. Whether a permit was issued for this work could not be confirmed from the available records.