Beaked and sperm whales are top predators living in the waters off the Kona coast of Hawai’i. Temporal and spatial analyses of the foraging activity of these two species were studied with passive acoustics techniques. Three passive acoustics recorders moored to the ocean floor were used to monitor the foraging activity of these whales in three locations along the Kona coast of the island of Hawaii. Data were analyzed using automatic detector/classification systems: M3R (Marine Mammal Monitoring on Navy Ranges), and custom-designed MATLAB programs. The temporal variation in foraging activity was species-specific: beaked whales foraged more at night in the north, and more during the day-time off Kailua-Kona. No day-time/night-time preference was found in the southern end of the sampling range. Sperm whales foraged mainly at night in the north, but no day-time/night-time preference was observed off Kailua-Kona and in the south. A Generalized Linear Model was then applied to assess whether location and chlorophyll concentration affected the foraging activity of each species. Chlorophyll concentration and location influenced the foraging activity of both these species of deep-diving odontocetes.

Here is a link to the paper: http://scitation.aip.org/content/asa/journal/jasa/140/4/10.1121/1.4964105

This paper is the last of a series of publication that aims at describing the foraging activity of deep diving odontocetes in different ocean basins /environments. The other publication are:

Giorli, G., Neuheimer, A., & Au, W. (2016). Spatial variation of deep diving odontocetes’ occurrence around a canyon region in the Ligurian Sea as measured with acoustic techniques. Deep Sea Research Part I: Oceanographic Research Papers, 116, 88-93.

Giacomo Giorli, Whitlow W. L. Au, Anna Neuheimer, (2016). Differences in the foraging strategy of deep diving odontocetes in the Ligurian Sea determined by passive acoustic recorders. Deep sea Research Part I, 107, 1-8. 

Giacomo Giorli, Whitlow W. L. Au, Helen Ou, Susan Jarvis, Ronald Morrissey, David Moretti, (2015). Acoustic detection of biosonar activity of deep diving Odontocetes at Josephine Seamount High Seas Marine Protected Area. J. Acoust. Soc. Am., 137, 2495.

Whitlow W. L. Au, Giacomo Giorli, Jessica Chen, Adrienne Copeland, Marc Lammers, Michael Richlen, Susan Jarvis, Ronald Morressey, David Moretti, Holger Klinck.(2013) Nighttime Foraging by Deep Diving Echolocating Odontocetes off the Hawaiian Islands of Kauai and Ni’iahu as Determined by Passive Acoustic Monitors. J. Acoust. Soc. Am. Volume 133, Issue 5, pp. 3119-3127.