Blainville's beaked whale (Mesoplodon densirostris)

Species >> Blainville's beaked whale (Mesoplodon densirostris)

Detailed information on diving (sub-surface) behavior of beaked whales (family Ziphiidae) is only available for one of the 21 recognized species. Information on diving behavior of additional species within the family Ziphiidae is needed to evaluate their susceptibility to impacts from anthropogenic sound (such as high-intensity sonars) and to develop correction factors for survey-based estimates of abundance or density.

Small-boat surveys were undertaken in March/April 2006 off the west side of the island of Hawai‘i for the purposes of obtaining dive data from Blainville’s (Mesoplodon densirostris) and Cuvier’s (Ziphius cavirostris) beaked whales, as well as collecting biopsy samples and photo identification of these and other species of odontocetes for studies of stock structure and residency patterns.

To assess movements and habitat use of beaked whales in Hawai‘i, satellite tags were remotely-deployed on two adult female Cuvier’s beaked whales (Ziphius cavirostris) and one adult female Blainville’s beaked whale (Mesoplodon densirostris) between October 2009 and April 2010.

Of the 18 species of odontocetes known to be present in Hawaiian waters, small resident populations of 11 species—dwarf sperm whales, Blainville’s beaked whales, Cuvier’s beaked whales, pygmy killer whales, short-finned pilot whales, melon-headed whales, false killer whales, pantropical spotted dolphins, spinner dolphins, rough-toothed dolphins, and common bottlenose dolphins—have been identified, based on two or more lines of evidence, including results from small-boat sightings and survey effort, photo-identification, genetic analyses, and satellite tagging.

Satellite tagging data for short-finned pilot whales (Globicephala macrorhynchus) and Blainville’s beaked whales (Mesoplodon densirostris) were used to identify core insular foraging regions off the Kona (west) Coast of Hawai‘i Island. Ship-based active acoustic surveys and oceanographic model output were used in generalized additive models (GAMs) and mixed models to characterize the oceanography of these regions and to examine relationships between whale density and the environment.