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POP2025-06 Updated population assessment for New Zealand fur seal (PDF, 937K)

Summary

The protected kekeno/New Zealand fur seal (Arctocephalus forsteri) is the most commonly bycaught marine mammal species in New Zealand’s commercial fisheries (MacKenzie et al. 2022), with 1,351 recorded bycatch deaths between the 2019/20 – 2025/26 fishing years (to date: 15/04/2026) (Ministry for Primary Industries 2026), and 1,908 recorded captures. Additional threats to kekeno include emerging diseases (Taylor et al. 2026, Ashley et al. 2026) and changes to prey availability
(Devine et al. 2025).

This report details activities undertaken to update knowledge of kekeno abundance and distribution. It includes updates to abundance estimates in four regions (Kaikōura, Mātakitaki-a-Kupe/Cape Palliser, The West Coast of the South Island (WCSI) and The Bounty Islands), an updated nationwide population estimate and an evidence-based framework for future kekeno
population monitoring.

A mark-recapture study to estimate kekeno abundance at Mātakitaki-a-Kupe/Cape Palliser in January 2026 was postponed to 2027 due to forecasted extreme weather. A preliminary direct count indicated at least 1,000 pups had been produced in the 2025/26 breeding season. This figure should be treated with caution, and mark-recapture will be conducted at this site to provide a robust assessment.

Mark-recapture and direct counts at six Kaikōura colonies estimated a total of 9,465 – 10,027 pups had been produced in the 2025/26 breeding season. All Kaikōura colonies experienced increases in pup production relative to 2024/2025. This may be a continued response to significantly reduced breeding in 2023/24, associated with an Unusual Mortality Event (UME).

Continued pup production declines were identified at Wekakura Point, Cape Foulwind and Taumaka Island (WCSI) from an analysis of a multi-decade population monitoring programme. The 2025 pup abundance estimates were 186 (178 – 194 95% CI) at Wekakura Point, 131 (122 – 140 95% CI) at Cape Foulwind and 566 (555 – 577 95% CI) at Taumaka Island. These figures represent declines of 83%, 71% and 61% respectively from each colony’s recorded maximum in the 1990s.

Drone surveys at the Bounty Islands (January 2024) estimated 4,252 – 4,341 pups had been produced, the first local assessment in three decades.

An updated nationwide population estimate for New Zealand’s kekeno was calculated using a pre-existing modelling framework, producing an estimate of 208,536 – 251,644 kekeno in 2026. Colonies where pup production data have never been collected could not be included in this estimate. The estimate could be improved by increasing the spatial coverage of regular kekeno
colony assessments, and through the collection of demographic data.

To track trends in kekeno abundance and consolidate understandings of what drives these trends, data collection is recommended for the following parameters:

• • Nationwide disease prevalence: to identify and respond to new diseases in New Zealand
    wildlife.
  • Pup production and body condition: to monitor trends in population abundance and health, and
    facilitate threat detection.
  • Marine distribution and foraging behaviour: to improve understandings of spatial and temporal
    overlap with commercial fisheries, and the impacts of climate change on prey availability.
  •  Diet: to detect changes in prey availability and assess resource competition with commercial
    fisheries.
  • Survival and fecundity: to facilitate population viability analyses to understand how the
    population may respond to threats.

A recommended framework for future kekeno monitoring involves combining studies at focal sites with coordinated nationwide surveys to track large-scale population trends. Suggested focal sites are:

• • West Coast South Island (Wekakura Point, Cape Foulwind and Taumaka Island colonies): due to an existing long-term dataset and longstanding concerns over bycatch rates.
  • Kaikōura (Ōhau Point, Kaikōura Peninsula and South Coast colonies): due to the recent UME, the detection of canine distemper virus (CDV) (Taylor et al. 2026), and the existence of a recently established monitoring programme.
  • Mātakitaki-a-Kupe/Cape Palliser: due to concerns over high bycatch rates (Pavanato et al. 2023) and the recent detection of CDV (Taylor et al. 2026).
  • Sandymount Colony (Otago Peninsula): due to an existing long-term dataset (Seddon et al., unpublished data; Appendix 4).

Publication information

Hall, A., Weir, J. 2026. Updated population assessment for New Zealand fur seal. Conservation Services Programme, Department of Conservation, Wellington, Aotearoa New Zealand. 63 p.