Changes in the movement and calling behavior of minke whales (Balaenoptera acutorostrata) in response to navy training

• Published in: Frontiers in Marine Science
• Main Authors: Durbach, Ian N., Harris, Catriona M., Martin, Cameron, Helble, Tyler A., Henderson, E. Elizabeth, Ierley, Glenn, Thomas, Len, Martin, Stephen W.
• Other Authors: University of St Andrews.School of Mathematics and Statistics, University of St Andrews.Centre for Energy Ethics, University of St Andrews.Office of the Principal, University of St Andrews.Scottish Oceans Institute, University of St Andrews.Centre for Research into Ecological & Environmental Modelling, University of St Andrews.School of Biology, University of St Andrews.Sea Mammal Research Unit, University of St Andrews.Statistics, University of St Andrews.Marine Alliance for Science & Technology Scotland
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Naval sonar; Passive acoustic monitoring; Behavioural response; Animal movement; Minke whale; GE Environmental Sciences; QA Mathematics; E-DAS; GE; QA; Pacific; Balaenoptera acutorostrata; baleen whale; minke whale
• Online Access: http://hdl.handle.net/10023/23718; https://doi.org/10.3389/fmars.2021.660122

This research was funded by the U.S. Office of Naval Research under grant number N000141612859. The passive acoustic data were recorded under support by COMPACFLT for the Navy Marine Species Monitoring Program. The call association tracking algorithm was developed under a separate U.S. Office of Naval Research project (2011–2015 Advanced Detection, Classification and Localization, grant number: N0001414IP20037). Many marine mammals rely on sound for foraging, maintaining group cohesion, navigation, finding mates, and avoiding predators. These behaviors are potentially disrupted by anthropogenic noise. Behavioral responses to sonar have been observed in a number of baleen whale species but relatively little is known about the responses of minke whales (Balaenoptera acutorostrata). Previous analyses demonstrated a spatial redistribution of localizations derived from passive acoustic detections in response to sonar activity, but the lack of a mechanism for associating localizations prevented discriminating between movement and cessation of calling as possible explanations for this redistribution. Here we extend previous analyses by including an association mechanism, allowing us to differentiate between movement responses and calling responses, and to provide direct evidence of horizontal avoidance responses by individual minke whales to sonar during U.S. Navy training activities. We fitted hidden Markov models to 627 tracks that were reconstructed from 3 years of minke whale (B. acutorostrata) vocalizations recorded before, during, and after naval training events at the U.S. Navy's Pacific Missile Range Facility, Kauai, Hawaii. The fitted models were used to identify different movement behaviors and to investigate the effect of sonar activity on these behaviors. Movement was faster and more directed during sonar exposure than in baseline phases. The mean direction of movement differed during sonar exposure, and was consistent with movement away from sonar-producing ships. Animals were also more likely to cease ...