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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Megafauna
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1394687

Movement and diving behavior of satellite-tagged male sperm whales in the Gulf of Alaska

Provisionally accepted
Lauren A. Wild Lauren A. Wild 1,2*Franz J. Mueter Franz J. Mueter 2Jan M. Straley Jan M. Straley 1Russel D. Andrews Russel D. Andrews 3
  • 1 University of Alaska Southeast, Juneau, United States
  • 2 College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, United States
  • 3 Marine Ecology and Telemetry Research (MarEcoTel), Seabeck, United States

The final, formatted version of the article will be published soon.

    Male sperm whales (Physeter macrocephalus) are known to interact with and depredate from commercial longline fishing vessels targeting sablefish (Anoplopoma fimbria) in the Gulf of Alaska (GOA). This study aims to better understand their movement patterns and diving behavior in this region, and in relation to depredation behavior. Between 2007 and 2016 a total of 33 satellite tags were deployed on sperm whales interacting with fishing vessels in the eastern GOA. A subset of these tags also collected dive characteristics. We used state space models to interpolate hourly positions from tags and estimate behavioral state from 29 usable tag records, 14 of which had associated dive information. Whales exhibited slower horizontal movement (1.4 km/hr) within GOA waters compared to south of the GOA (5.5 km/hr), indicating tagged whales sped up when they left the region. Behavioral states indicated primarily foraging behavior (82% of locations) in the GOA and primarily transiting behavior (74% of locations) when whales left the GOA. Dive data showed average (±Standard Deviation) maximum dive depths of 396 m (±166), and dive durations of 32 min (± 9). Generalized additive models indicated that dives were significantly deeper and longer during the daytime than dawn, dusk, or nighttime, and dives were significantly deeper and shorter during quarter moons, when tidal currents are weakest. Maximum dive depth decreased in areas of higher sablefish CPUE, suggesting a potential link between the sablefish fishery and depredation behavior. As seafloor depth increased, up to 800 m, dives became deeper, indicating that whales were likely targeting both bathypelagic and mesopelagic prey. This highlights the importance of the GOA continental slope as a foraging ground for male sperm whales. This enhanced understanding of sperm whale foraging ecology informs management and conservation efforts in high latitude foraging grounds.

    Keywords: sperm whale1, Gulf of Alaska2, satellite tag3, sablefish4, diving5. (Min.5-Max. 8 behavioral states from irregular, satellite-derived location data (Aarts 180

    Received: 01 Mar 2024; Accepted: 29 Jul 2024.

    Copyright: © 2024 Wild, Mueter, Straley and Andrews. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Lauren A. Wild, University of Alaska Southeast, Juneau, United States

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.