Palmyra Atoll IMMA
Qualifying Species and Criteria
Melon-headed whale – Peponocephala electra
Criterion B (2); D (1)
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Melon-headed whales (Peponocephala electra) around Palmyra Atoll in the Central Pacific Ocean display an unusual, distinct, daily activity pattern of nearshore habitat use similar to the regular daily cycles of inshore resting and socializing shown by spinner dolphins. The IMMA includes the nearshore waters of the atoll along the north and south coasts which are important for the resting and socializing of the Melon-headed whale aggregations.
Description of Qualifying Criteria
Criterion B: Distribution and Abundance
Sub-criterion B2: Aggregations
Melon-headed whales have been regularly recorded in aggregations of several hundred individuals in inshore areas around Palmyra Atoll (Brownell et al. 2009). The whales display a distinct daily activity pattern of unusual near-shore habitat use, and stay close to the reef during morning to midday to rest. They can be observed resting along the north and south shore in the vicinity of land, never around the open eastern or western terrace. They remain in waters at least 100 m deep but never enter the atoll’s lagoon (Brownell et al. 2009).
Criterion D: Special Attributes
Sub-criterion D1: Distinctiveness
Based on mtDNA control region haplotypes and nuclear microsatellites, melon-headed whales from Palmyra Atoll were differentiated from all other sampled populations in the central Pacific and from most other sampled populations (Martien et al. 2017). There is high confidence in this assessment of differentiation because of the large number of samples from Palmyra (n=56).
Brownell Jr, R.L., Ralls K., Baumann-Pickering, S. and Poole, M.M. 2009. Behavior of melon-headed whales, Peponocephala electra, near oceanic islands. Marine Mammal Science 25:639-658.
Martien, K. K., Hancock-Hanser, B. L., Baird, R. W., Kiszka, J., Aschettino, J. M., Oremus, M. anf Hill. M. C. 2017. Unexpected patterns of global population structure in melon-headed whales (Peponocephala electra). Marine Ecology Progress Series doi: 10.3354/meps12203