| Autor: |
Abecassis M; Joint Institute for Marine and Atmospheric Research, University of Hawai'i, Honolulu, HI, United States of America., Polovina J; Pacific Islands Fisheries Science Center, NOAA Fisheries, Honolulu, HI, United States of America., Baird RW; Cascadia Research Collective, Olympia, WA, United States of America., Copeland A; Hawai'i Institute of Marine Biology, University of Hawai'i, Kāne'ohe, HI, United States of America., Drazen JC; Department of Oceanography, University of Hawai'i, Honolulu, HI, United States of America., Domokos R; Pacific Islands Fisheries Science Center, NOAA Fisheries, Honolulu, HI, United States of America., Oleson E; Pacific Islands Fisheries Science Center, NOAA Fisheries, Honolulu, HI, United States of America., Jia Y; International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawai'i, Honolulu, HI, United States of America., Schorr GS; Cascadia Research Collective, Olympia, WA, United States of America., Webster DL; Cascadia Research Collective, Olympia, WA, United States of America., Andrews RD; Alaska SeaLife Center, Seward, AK, United States of America.; School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, United States of America. |
| Abstrakt: |
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. |
