South Taranaki Bight IMMA

Size in Square Kilometres

47,361 km2

Qualifying Species and Criteria

Māui dolphin – Cephalorhynchus hectori maui

Criterion A

Hector’s dolphin – Cephalorhynchus hectori

Criterion A

Pygmy blue whale – Balaenoptera musculus brevicauda

Criterion A; C (2, 3); D (1)

New Zealand fur seal – Arctocephalus forsteri

Criterion C (1)

Antarctic blue whale – Balaenoptera musculus intermedia

Criterion A

Humpback whale – Megaptera novaeangliae

Criterion A; C (3)

Fin whale – Balaenoptera physalus

Criterion A

Sei whale – Balaenoptera borealis

Criterion A

Sperm whale – Physeter macrocephalus

Criterion A

Southern right whale – Eubalaena australis

Criterion C (3)

Common dolphin – Delphinus delphis

Criterion C (2)

Killer whale – Orcinus orca

Criterion D (1)

Marine Mammal Diversity 

Criterion D (2)

Globicephala melas, Caperea marginata, Tasmacetus shepherdi, Mesoplodon bowdoini, Balaenoptera bonaerensis, Berardius arnuxii, Tursiops truncatus, Balaenoptera edeni, Lobodon carcinophaga, Ziphius cavirostris, Lagenorhynchus obscurus, Pseudorca crassidens, Mesoplodon ginkgodens, Mesoplodon grayi, Mesoplodon hectori, Hydrurga leptonyx, Stenella attenuata, Kogia breviceps, Grampus griseus, Steno bredanensis, Globicephala macrorhynchus, Hyperoodon planifrons, Mirounga leonine, Lissodelphis peronii, Phocoena dioptrica, Mesoplodon layardii, Stenella coeruleoalba

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The South Taranaki Bight mostly comprises shallow shelf waters (~100-120m) and is strongly influenced by a nutrient-rich upwelling system. Over 35 different marine mammal species have been documented within the region including at least eight species or subspecies with IUCN threatened or vulnerable status (e.g. Māui dolphins, Antarctic blue whale – both CR, Hector’s dolphin, pygmy blue whale, Oceania sub-population humpback whale, sei whale – all four EN, fin whale, sperm whale – both VU). New Zealand pygmy blue whales are a genetically distinct and isolated population with year-round presence in the region, which is a critical foraging ground. Hector’s dolphins and Māui dolphin occur in the coastal waters of the South Taranaki Bight. The IMMA which is used as a migratory corridor for humpback, blue, and southern right whales, and includes colonies of New Zealand fur seals. The South Taranaki Bight region has relatively high levels of anthropogenic activities.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

There are eight species or subspecies found in the IMMA that meet this criterion with IUCN threatened or vulnerable status (e.g. Maui dolphins (CR), Antarctic blue whale (CR), Hector’s dolphin (EN), pygmy blue whale (EN), humpback whale (Oceania sub-population; EN), sei whale (EN), fin whale (VU), sperm whale (VU)). All these species have been reported from the IMMA (e.g. DOC Marine Mammal Sighting and Stranding database 2020) and this IMMA forms an important part of their range within New Zealand.  The IMMA forms an important feeding area for a range of marine mammal species with the Kahurangi upwelling system recognised as a highly productive source of food for marine mammals within the area.

Criterion C: Key Life Cycle Activities

Sub-criterion Ci: Reproductive Areas

Important New Zealand fur seal breeding colonies (e.g. Kahurangi Point, Steep Point, Wekakura Point) occur along the north west coast of the South Island whose coastal and offshore feeding (particularly for nursing females) are constrained to feeding completely within the IMMA during the breeding season (Baker et al. 2010). The region is also likely to be important for a range of other species (e.g. Hector’s, blue whales, southern right whales, pilot whales, common dolphins) which have been observed with young calves in the region but for which there is little systematic information (DOC Marine Mammal Sighting and Stranding database 2020).

Sub-criterion Cii: Feeding Areas

The Kahurangi upwelling system sustains high productivity in the South Taranaki Bight region leading to high densities of krill biomass that make the area an important feeding area for pygmy blue whales (Torres 2013, Barlow et al. 2018; Barlow et al. 2020) and may also be important for other species including fin, sei and potentially Bryde’s whales. This same system also likely provides important feeding grounds for long finned pilot whales, pygmy right whales and Shepherd’s beaked whales which are reported from regular visual sightings and / or stranding records from the IMMA (DOC Marine Mammal Sighting and Stranding database 2020). Common dolphins are also regularly reported from the IMMA including regular bycatch in commercial trawl fisheries providing strong indication that this is an important feeding area for them (MPI 2017). Various other species (e.g. Hector’s, blue whales, fur seals, sperm whales, southern right whales, pilot whales, common dolphins) have also been recorded feeding in this area but there is little information available about these species (DOC Marine Mammal Sighting and Stranding database 2020).

Sub-criterion Ciii: Migration Routes

Historical whaling data confirms this IMMA as an important migration route for humpback whales and southern right whales (Dawbin 1956, Richards et al. 2009). Recent records have also confirmed that this IMMA still contains important migratory pathways for humpback, southern right whales, and blue whales (Bott et al. 2017, Carroll et al. 2013, Barlow et al. 2021, Goetz et al. 2018). While there is little data for other species, it is likely that this IMMA is also important for other species such as fin, sei, sperm and Bryde’s whales.

Criterion D: Special Attributes

Sub-criterion Di: Distinctiveness

The pygmy blue whales of New Zealand are genetically distinct from all other populations in the Southern Hemisphere (Barlow et al. 2018). Furthermore, no matches had been made between a photo-id catalogue of 174 New Zealand blue whales and photo-id images of blue whales captured in Australia (n = 197) or Antarctic (n = 65) (Barlow et al. 2018). Also, killer whales in New Zealand are considered distinctive to other killer whales around the Southern Hemisphere (Baker et la. 2019).

Sub-criterion Dii: Diversity

This IMMA supports a wide range of marine mammal species including over 35 different marine mammal species recorded including the main species such as Māui dolphin, Hector’s dolphin, pygmy blue whale, New Zealand fur seal, humpback whale, sperm whale, southern right whale, common dolphin and and killer whale (e.g. DOC Marine Mammal Sighting and Stranding database 2020). Other species recorded further include Andrew’s beaked whale, antarctic minke whale, Arnoux’s Beaked whale, common bottlenose dolphin, Bryde’s whale, crabeater seal, Cuvier’s beaked whale, dusky dolphin, false killer whale, ginkgo-toothed beaked whale, Gray’s beaked whale, Hector’s beaked whale, leopard seal, pantropical spotted dolphins, pygmy sperm whale, Risso’s dolphin, rough toothed dolphin, short-finned pilot whale, southern bottlenose whale, southern elephant seal, southern right whale dolphin, spectacled porpoise, strap-toothed beaked whale, striped dolphin, and the presence of other unrecorded species highly likely.

Supporting Information

Baker, B, Jensz, K., Cawthron, M. and Cunningham, R. 2010. Census of New Zealand Fur Seals on the West Coast of New Zealand’s South Island. Report prepared for Deepwater Group Limited. March 2010. 24 p.

Baker, C.S., Boren, L., Childerhouse, S., Constantine, R., van Helden, A., Lundquist, D., Rayment, and W., Rolfe, J.R. 2019. Conservation status of New Zealand marine mammals, 2019. New Zealand Threat Classification Series 29. Department of Conservation, Wellington. 18 p.

Baker, C.S., Steel, D., Hamner, R., Constantine, R., Ogle, M., and Tai, A. 2017. Note on individual identification, sex and mtDNA haplotypes of Hector’s dolphins sampled in Queen Charlotte Sound, with comparison to Golden Bay. Progress Report to Department of Conservation, Wellington, New Zealand

Balcazar, N.E., Tripovich, J. S., Klinck, H., Nieukirk, S.L., Mellinger, D.K., Dziak, R.P., and Rogers, T.L. 2015. Calls reveal population structure of blue whales across the southeast Indian Ocean and southwest Pacific Ocean. Journal of Mammalogy 96: 1184-1193.

Barlow, D., Torres, L., Hodge, K., et al. 2018. Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research 36:27-40.

Barlow, D.R., Bernard, K.S., Escobar-Flores, P., Palacios, D.M., and Torres L.G. 2021. Links in the trophic chain: Modeling functional relationships between in situ oceanography, krill, and blue whale distribution under different oceanographic regimes. Marine Ecology Progress Series, 642:207-225.

Bott, N., Dunlop, R., Gibbs, J., Heberly, J., and Olavarria, C. 2017. The potential beginning of a post-whaling recovery in New Zealand humpback whales (Megaptera novaeangliae). Marine Mammal Science 34: 499-513.

Bradford-Grieve, J.M., Murdoch, R.C., and Chapman, B.E. 1993. Composition of macrozooplankton assemblages associated with the formation and decay of pulses within an upwelling plume in greater Cook Strait, New Zealand. New Zealand Journal of Marine and Freshwater Research 27:1-22.

Bradshaw, CJ.A., Davis, L.S., Purvis, M., Zhou, Q., and Benwell, G.L. 2002. Using artificial neural networks to model the suitability of coastline for breeding by New Zealand fur seals (Arctocephalus forsteri). Ecological Modelling 148: 111-131

Carroll, E., Rayment, W., Alexander, A., Baker, C.S., Patenaude, N., Steel, D., Constantine, R., Cole, R., Boren, L., and Childerhouse, S. 2013. Reestablishment of former wintering grounds by New Zealand southern right whales. Marine Mammal Science 30(1): 206-220.

Dawbin, W.H. 1956. The migration of humpback whales which pass the New Zealand coast. Trans. R. Soc. NZ 84(1): 147–96.

Dawson, S., Pichler, F., Slooten, E., Russell, K., and Baker, C.S. 2001. The North Island Hector’s dolphin is vulnerable to extinction. Marine Mammal Science 17:366-371

Galletti Vernazzani, B., Attard, C., Barlow, D.R., Burton, C., de Vos, A., Double, M., Gill, P., Jenner, C., Jenner, M.-C., Moller, L., Olson, P., Salgado-Kent, C., Torres, L.G. 2018. Preliminary results of 2017 IWC comparisons among Southern Hemisphere blue whale catalogues off Australia, New Zealand and Sri Lanka regions. Report SC/67B/SH/16 to the Scientific Committee of the International Whaling Commission.

Goetz, K., Childerhouse, S., Paton, D., Hupman, K., Constantine, R., Double, M., Andrews-Goff, V., Zerbini, A., and Olsen, P. 2018. Satellite tracking of blue whales in New Zealand waters, 2018 voyage report. Report to the Scientific Committee of the International Whaling Committee. SC/67B/SH/09 Rev2.

Hamner, R.M., Pichler, F.B., Heimeier, D., Constantine, R., and Baker, C.S. 2012. Genetic differentiation and limited gene flow among fragmented population of New Zealand endemic Hector’s and Maui’s dolphins. Conservation Genetics 13: 987-1002

Hamner, R.M. ;Constantine, R., Oremus, M., Stanley, M., Brown, P., and Baker, C.S. 2014. Long-range movement by Hector’s dolphins provides potential genetic enhancement for critically endangered Maui’s dolphin. Marine Mammal Science 30: 139-153

MacKenzie, D.I. and Clement, D.M. 2016. Abundance and distribution of WCSI Hector’s dolphin: Supplemental Material. New Zealand Aquatic Environment and Biodiversity Report No. 168, Ministry for Primary Industries, Wellington, New Zealand

Ministry of Primary Industries (MPI) 2017. Common dolphins. In: Aquatic Environment and Biodiversity Annual Review 2017. Compiled by the Fisheries Science Team, Ministry for Primary Industries, Wellington, New Zealand. p 171-194.

New Zealand Department of Conservation (DOC) 2020. Marine Mammal Sighting and Stranding database. Public database maintained by DOC on behalf of New Zealand Government. Available from Accessed in June 2020.

Olson, P.A., Ensor, P., Olavarria, C., Bott, N., Constantine, R., Weir, J., Childerhouse, S., van der Linde, M., Schmitt, N., Miller, B.S., and Double, M.C. 2015. New Zealand blue whales: Residency, morphology, and feeding behavior of a little-known population. Pacific Science 69: 477-485

Richards, R. 2009. Past and present distributions of southern right whales (Eubalaena australis). New Zealand Journal of Zoology 36(4): 447-459

Roberts, J.O., Webber, D.N., Roe, W.D., Edwards, C.T.T., and Doonan, I.J. 2019a. Spatial risk assessment of threats to Hector’s and Māui dolphins (Cephalorhynchus hectori). New Zealand Aquatic Environment and Biodiversity Report No. 214. Fisheries New Zealand, Wellington, New Zealand, pp. 168

Torres, L. G. 2013. Evidence for an unrecognised blue whale foraging ground in New Zealand. New Zealand Journal of Marine and Freshwater Research 47: 235-248


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