Pup numbers, estimated population size, and monitoring of New Zealand fur seals in Doubtful/Pateā, Dusky and Breaksea Sounds, and Chalky Inlet, Fiordland, New Zealand 2021

ABSTRACT

New Zealand fur seals (Arctocephalus forsteri) are expanding in numbers and distribution throughout New Zealand. The exception is the West Coast of the South Island, where there is documented decline due to decades of mortalities related to fishery. There are fur seal colonies south of these West Coast colonies, in Fiordland, which have never been accurately documented or monitored. Even for those that are documented, there are few records of pup numbers and no population estimates. Here, pups at colonies from Doubtful/Pateā, Dusky, and Breaksea Sound, and Chalky Inlet were observed, and their numbers either counted directly or estimated using mark-recapture methods in February 2021. From these pup counts a coarse minimum population estimate of between 14–24 thousand fur seals is calculated for lower Fiordland. The pup counts and population estimates indicated the fur seal numbers are higher than previously recorded from estimates of walk through, boat or helicopter observations. During onshore surveys and from anecdotal evidence, it was noted that fur seals were rearing pups in forested areas. This paper outlines suggestions for the future monitoring of these colonies given, location, diverse geology and the difficulty of monitoring colonies on exposed west coast areas of New Zealand’s Fiordland.

KEYWORDS:

• Arctocephalus forsteri
• New Zealand
• mark-recapture
• population estimate‌
• pup count

Acknowledgements

Thank you to Chloe Corne, Nic White, Pete Young, Ross Funnell, Richard Kinsey, Monique Ladds and everyone else on Southernwinds that made this such a great trip. Big thank you to Department of Conservation Te Anau for logistical help and access to the Southernwinds vessel for 10 days. This research was conducted under the Massey University Animal Ethics permit MUAE 20/71 and under Department of Conservation Marine Mammal Management.

Disclosure statement

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

Additional information

Funding

This work was supported by the Department of Conservation and Massey University.