Characterizing a Foraging Hotspot for Short-Finned Pilot Whales and Blainville's Beaked Whales Located off the West Side of Hawai'i Island by Using Tagging and Oceanographic Data

PLoS One. 2015 Nov 25;10(11):e0142628. doi: 10.1371/journal.pone.0142628. eCollection 2015.

Abstract

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. The regions of highest density for pilot whales and Blainville's beaked whales were located between the 1000 and 2500 m isobaths and the 250 and 2000 m isobaths, respectively. Both species were associated with slope waters, but given the topography of the area, the horizontal distribution of beaked whales was narrower and located in shallower waters than that of pilot whales. The key oceanographic parameters characterizing the foraging regions were bathymetry, temperature at depth, and a high density of midwater micronekton scattering at 70 kHz in 400-650 m depths that likely represent the island-associated deep mesopelagic boundary community and serve as prey for the prey of the whales. Thus, our results suggest that off the Kona Coast, and potentially around other main Hawaiian Islands, the deep mesopelagic boundary community is key to a food web that supports insular cetacean populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustics
  • Animal Migration / physiology*
  • Animals
  • Diving
  • Echolocation
  • Food Chain
  • Hawaii
  • Islands
  • Oceanography
  • Population Density
  • Predatory Behavior / physiology*
  • Satellite Imagery
  • Time Factors
  • Vocalization, Animal / physiology
  • Whales / physiology*
  • Whales, Pilot / physiology*

Grants and funding

This work was supported by Project 13–11 from the NOAA Fisheries and the Environment program: http://www.st.nmfs.noaa.gov/fate/Resources/Projects/index (MA), Grants No. N00140811203 and N000141010686 from Office of Naval Research, www.onr.navy.mil (RDA, RWB, GSS, DLW), Grant No. N000141110612 from ONR, www.onr.navy.mil (RWB, DLW), Grant No. N000141210205 from ONR, www.onr.navy.mil (AC), Sub-contract No. D100115 from Woods Hole Oceanographic Institution, www.whoi.edu (RWB, GSS, DLW) and Contracts AB133F07CN0220, AB133F08SE4534, AB133F09SE4843 from NOAA Fisheries to Cascadia Research Project (RWB, GSS, DLW). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.