Cook Islands Southern Group IMMA

Area Size

431 498 km2

Qualifying Species and Criteria

Humpback whale – Megaptera novaeangliae

Criterion A; C (1, 3)

Spinner dolphin – Stenella longirostris

Criterion B (1); C (1)

Marine Mammal Diversity 

Criterion D (2)

Balaenoptera bonaerensis, Mesoplodon densirostris, Balaenoptera musculus, Balaenoptera edeni, Ziphius cavirostris, Pseudorca crassidens, Balaenoptera physalus, Lagenodelphis hosei, Peponocephala electra, Balaenoptera omurai, Feresa attenuata, Steno bredanensis, Balaenoptera borealis, Globicephala macrorhynchus, Physeter macrocephalus

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The Southern Group of the Cook Islands, includes Palmerston, Aitutaki, Manuae, Atiu, Takutea, Mitiaro, Mauke, and the Eclipse Seamount, which form a linear volcanic island chain, and also Rarotonga and Mangaia which belong to a separate linear system composed primarily of seamounts. This IMMA is considered important habitat for breeding and migrating humpback whales of the Endangered Oceania subpopulation, as well as many small and resident populations of spinner dolphins around each of the islands.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

Humpback whales across Oceania are listed as Endangered on the IUCN Red List, and the Cook Islands represent important habitat for this vulnerable population during the austral winter.  Nineteen years of humpback whale research around Rarotonga, Aitutaki, Mangaia, Atiu and Palmerston has generated a large amount of information including photo and genetic identification of individuals, acoustics, communication, and behaviour, migration patterns by satellite tagging, population identity and abundance (Hauser and Clapham, 2005).

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Spinner dolphins occur around the south-eastern islands of Rarotonga, Mangaia, and Palmerston and photo-ID data describe the long-term residency (Cook Islands Whale Research Annual Reports, 1998 to 2016).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

The Southern Cook Islands represent a calving ground for humpback whales during the austral winter. Humpback whale calves are born between early June and late October, close to the shores of all the Islands in the Southern Cook’s Group IMMA (Hauser and Clapham 2005). This is indicated by the presence of mothers with calves in the area, the sightings and acoustic detection of many singers, as well as the observation of competitive groups (Hauser and Clapham, 2005). In addition, calves have been observed in the resident pods of Spinner dolphins that occur in the south-eastern Islands of Rarotonga, Mangaia, and Palmerston (Cook Islands Whale Research Annual Reports, 1998 to 2016).

Sub-criterion C3: Migration Routes

Connectivity between feeding and breeding grounds of Oceania humpback whales has been revealed by comparing photo-ID catalogues, molecular markers, and song, as well as by satellite tagging all conducted through the activities of the South Pacific Whale Research Consortium (Olavarria, Baker, Garrigue, et al. 2007; Hauser et al. 2009). In particular, recent satellite tagging showed that humpback whales in the Cook Islands migrated on to Tonga and Samoa, and therefore the Cook Islands is part of the whale migration route connecting other feeding and breeding areas (Garrigue, Aguayo, Amante-Helweg, et al. 2002).

Criterion D: Special Attributes  

Sub-criterion D2: Diversity

The Southern Group of the Cook Islands IMMA contains habitat supporting an important diversity of cetaceans within the Pacific Islands Region, with up to 15 species having been observed (Cook Islands Whale Research Annual Reports, 1998 to 2016). These include deep diving species such as sperm whales, Blainville’s beaked whales, Cuvier’s beaked whales, and other migratory baleen whales including Sei whales, and Blue whales (Hauser, Peckham, Clapham 2000). Antarctic minke whales, and Omura’s whales have also been recorded (Cook Islands Whale Research Annual Reports, 1998 to 2016). However, the frequency that these animals are observed do not currently support specific individually important areas for these species.

Supporting Information

Constantine, R., Garrigue, C., Steel, D., Jackson, J., Burns, D., Clapham, P, Hauser, N., Mattila, D., Oremus, M., Poole, M., Robbins, J., Thompson, K., Baker, C.S. 2010. Abundance of humpback whales in Oceania based on fluke photo-identification and DNA profiling. Report SC/ 62/ SH18 presented to the International Whaling Commission, 30 May-11 June 2010, Agadir, Morocco.

Constantine, R., Jackson, J. A., Steel, D., Baker, C. S., Brooks, L., Burns, D., et al. 2012. Abundance of humpback whales in Oceania using photo-identification and microsatellite genotyping. Marine Ecology Progress Series, 453, 249-261. doi:10.3354/meps09613.

Cook Islands Whale Research Annual Reports, 1998 to 2016. Office of the Prime Minister, Cook Islands; The University of The South Pacific, Suva, Fiji; Cook Islands National Environment Services; The Whale & Wildlife Centre, Rarotonga [AVAILABLE ON REQUEST].

Garrigue, C., Aguayo, A., Amante-Helweg, V.L.U., Baker, C.S., Caballero, S., Clapham, P., Constantine, R., Denkinger, J., Donoghue, M., Flórez-González, L., Greaves, J., Hauser, N., Olavarría, C., Pairoa, C., Peckham, H., Poole, M. 2002. Movements of humpback whales in Oceania, South Pacific. Journal of Cetacean Research and Management 4(3): 255-260, 2002.

Hauser, N., Peckham, H. and Clapham, P.J. 2000. Humpback whales in the southern Cook Islands, South Pacific. Journal of Cetacean Research and Management 2: 159-164.

Hauser, N. and Clapham, P. 2002. The Cook Islands Whale Sanctuary, Paper SC/54/011 presented to the International Whaling Commission Scientific Committee.

Hauser, N., and Clapham, P. 2005. Occurrence and habitat use of humpback whales in the Cook Islands. Document SC/A06/HW49 presented to the International Whaling Commission Scientific Committee.

Hauser, N., Zerbini, A., Geyer, Y., Heide-Jorgensen, M-P., Clapham, P. 2007. Migratory destination of a humpback whale satellite-tagged in the Cook Islands. Paper SC/59/SH12 presented to the International Whaling Commission Scientific Committee.

Hauser, N., Zerbini, A., Geyer, Y., Heidi-Jørgensen, M.P. & Clapham, P. 2010. Movements of Satellite-Monitored Humpback Whales, Megaptera novaeangliae, from the Cook Islands. Marine Mammal Science. 26(3): 679-685.

Olavarría, C., Baker, C.S., Garrigue, C., Poole, M., Hauser, N., Caballero, S., Flórez-González, L., Brassuer, M., Capella, J., Clapham, P., Dodemont, R., Donoghue, M., Jenner, M. N., Moro, D., Oremus, M., Paton, D. and Russell, K. 2007. Population structure of humpback whales throughout the South Pacific, and the origin of the eastern Polynesian breeding grounds. Marine Ecology Progress Series 330: 257-268.

Steel, D., Garrigue, C., Poole, M., Hauser N., Olavarria, C., Florez-Gonzalez, L., Constantine, R., Caballero, S., Thiele, D., Paton, D., Clapham, P., Donoghue, M., Baker, C.S. 2008. Migratory connections between humpback whales from South Pacific breeding grounds and Antarctic feeding areas demonstrated by genotype matching. Report SC/60/SH13 presented to the Scientific Committee of the International Whaling Commission, 2-15 June, Santiago, Chile


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