Documentation of a New Zealand blue whale population based on multiple lines of evidence




Hamner, Rebecca M.
Barlow, Dawn
Torres, Leigh
Hodge, Kristin
Steel, Debbie
Baker, C. Scott
Chandler, Todd
Bott, Nadine
Constantine, Rochelle
Double, Michael


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Species conservation depends on robust population assessment. Data on population abundance, distribution, and connectivity are critical for effective management, especially as baseline information for newly documented populations. We describe a pygmy blue whale Balaenoptera musculus brevicauda population in New Zealand waters with year-round presence that overlaps with industrial activities. This population was investigated using a multidisciplinary approach, including analysis of survey data, sighting records, acoustic data, identification photographs, and genetic samples. Blue whales were reported during every month of the year in the New Zealand Exclusive Economic Zone, with reports concentrated in the South Taranaki Bight (STB) region, where foraging behavior was frequently observed. Five hydrophones in the STB recorded the New Zealand blue whale call type on 99.7% of recording days (January to December 2016). A total of 151 individuals were photo-identified between 2004 and 2017. Nine individuals were resighted across multiple years. No matches were made to individuals identified in Australian or Antarctic waters. Mitochondrial DNA haplotype frequencies differed significantly between New Zealand (n = 53 individuals) and all other Southern Hemisphere blue whale populations, and haplotype diversity was significantly lower than all other populations. These results suggest a high degree of isolation of this New Zealand population. Using a closed capture-recapture population model, our conservative abundance estimate of blue whales in New Zealand is 718 (SD = 433, 95% CI = 279-1926). Our results fill critical knowledge gaps to improve management of blue whale populations in New Zealand and surrounding regions.



blue whales, new zealand, photo-identification, abundence, acoustics, genetics, population connectivity, conservation


Funding for this project was provided by The Aotearoa Foundation, The New Zealand Department of Conservation, The National Geographic Society Waitt Foundation, The Marine Mammal Institute at Oregon State University, The National Oceanographic and Atmospheric Administration’s Cooperative Institute for Marine Resources Studies (NOAA/CIMRS), Greenpeace New Zealand, OceanCare, Kiwis Against Seabed Mining, The International Fund for Animal Welfare, The Thorpe Foundation, and an anonymous donor. The project was accomplished through the dedicated work and support of many individuals including the crew of the RV ‘Star Keys’ (Western Work Boats) and the RV ‘Ikatere’ (National Institute of Water and Atmospheric Research), Kathy Minta and Minda Stiles from Oregon State University, Ian Angus, Laura Boren, Hannah Hendriks, Andrew Lamason, and Dave Lundquist from the New Zealand Department of Conservation, and Edward James Moore III from the Bioacoustics Research Program at Cornell University. Blue whale sightings and photo-identification contributions are also recognized from Blue Planet Marine, the Ministry for Primary Industries, OMV, Petroleum Geo-Services, Dolphin Safari, Whale Watch Kaikoura, and the following individuals: Olive Andrews, Haley Baxter, Aneke Bowker, Jaime Brown, Deanna Clement, Sonja Clemens, Tony Crocker, Eric de Boer, Nico de la Brosse, Sarah Dwyer, Deanna Elvines, Viraj Gamage, Sarah Gardner, Dan Govier, Theresa Kirchner, Krista Hupman, Helen McConnell, Don Neale, Terry Visser, Jody Weir, and Roger Williams.


Attribution 4.0 International


Barlow DR, Torres LG, Hodge KB, Steel D and others (2018) Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endang Species Res 36:27-40.