Species-typical behavior, social structure, and habitat use of multiple resident species of odontocetes have been studied off Kauaʻi and Niʻihau in the Main Hawaiian Islands since 2003. These studies have used a suite of methods, including photo-identification, passive acoustics, tagging, and biopsy sampling. Starting in 2011, these efforts were timed to precede and overlap biannual US Navy training events conducted on the Pacific Missile Range Facility in order to measure the exposure levels from mid-frequency active sonars (MFAS) and assess potential behavioral responses of tagged odontocetes to training activities. This chapter describes the early received level work, highlights improvements to analyses over the years, and summarizes some of the findings of this long-term study. Some initial quantitative attempts are also detailed to identify behavioral responses to training activity for some species, including dense-beaked whales (Mesoplodon densirostris) and rough-toothed dolphins (Steno bredanensis), which include changes in diving and horizontal avoidance of sources in some, but not all, instances, depending on species and context. These findings provide some of the first ever data on known repeated exposures of individuals and populations to MFAS for some species, which will allow investigations into long-term consequences of exposures.
Citation:
Henderson, E.E., R.W. Baird, S.W. Martin, M.A. Kratofil, A.E. Harnish, S.D. Mahaffy, C.R. Martin, and B.L. Southall. 2026. A Review of the Long-Term Study of Resident Odontocetes Off Kauaʻi and Nʻiihau and the Analysis of Exposures to Mid-Frequency Active Sonar. Pages 1-13 in The Effects of Noise on Aquatic Life IV. Edited by A.N. Popper, J.A. Sisneros, P.A. Lepper, and K.J. Vigness-Raposa. Springer. doi: 10.1007/978-3-031-94229-7_4-1
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