Beaked whales have stereotypic upswept echolocation clicks that differ from other toothed whales. An unknown type of beaked whale click was first detected on Cross Seamount, to the west of Hawaiʻi Island, and has been termed BWC by acousticians. Since then, it has been documented on High-frequency Acoustic Recording Packages (HARP) off Kona and Kauaʻi (and on the Navy’s hydrophone range off Kauaʻi), at Manawai (Pearl & Hermes Atoll) in the northwestern Hawaiian Islands, and at several other sites in the western and central Pacific. Based on the geographic distribution of these signals and the known or suspected range of beaked whales species in the Pacific, Simone Baumann-Pickering and collaborators suggested that these signals may be made by ginkgo-toothed beaked whales (Mesoplodon ginkgodens), but this has not yet been confirmed. We have not knowingly seen this species in our work, although we always hope! Getting head photos, or a genetic sample, may be required in order to confidently identify which species this represents.

Recent references on Cross Seamount beaked whales

Baumann-Pickering, S., M.A. Roch, R.L. Brownell Jr, A.E. Simonis, M.A. McDonald, A. Solsona-Berga, E.M. Oleson, S.M. Wiggins, and J.A. Hildebrand. 2014. Spatio-temporal patterns of beaked whale echolocation signals in the North Pacific. PLoS ONE 9(1):e86072.

Johnston, D.W., M. McDonald, J. Polovina, R. Domokos, S. Wiggins, and J. Hildebrand. 2008. Temporal patterns in the acoustic signals of beaked whales at Cross Seamount. Biology Letters 4:208-211.

Manzano-Roth, R., E.E. Henderson, G.C. Alongi, C.R. Martin, S.W. Martin, B. Matsuyama. 2023. Dive characteristics of Cross Seamount
beaked whales from long-term passive acoustic monitoring at the Pacific Missile Range Facility, Kauaʻi. Marine Mammal Science  https://doi.org/10.1111/mms.12959

McDonald, M.A, J.A. Hildebrand, S.M. Wiggins, D.W. Johnston, and J. Polovina. 2009. An acoustic survey of beaked whales at Cross Seamount near Hawaii. Journal of the Acoustical Society of America 125(2), 624-627.