Behavioral responses of fin whales to military mid-frequency active sonar

• Published in: Royal Society Open Science
• Main Authors: Southall, Brandon, Allen, Ann N., Calambokidis, John, Casey, Caroline, DeRuiter, Stacy L., Fregosi, Selene, Friedlaender, Ari S., Goldbogen, Jeremy, Harris, Catriona M, Hazen, Elliot L., Popov, Valentin Mina, Stimpert, Alison K
• Other Authors: Naval Facilities Engineeering, University of St Andrews. School of Biology, University of St Andrews. Centre for Energy Ethics, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Centre for Research into Ecological & Environmental Modelling, University of St Andrews. Sea Mammal Research Unit, University of St Andrews. Office of the Principal, University of St Andrews. Statistics
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Noise; Marine mammals; Mid-frequency sonar; Fin whales; Behaviour; QH301 Biology; DAS; SDG 14 - Life Below Water; QH301; Balaenoptera musculus; Balaenoptera physalus
• Online Access: https://hdl.handle.net/10023/28887; https://doi.org/10.1098/rsos.231775

Funding. Primary funding for the SOCAL-BRS project was initially provided by the US Navy’s Chief of Naval Operations Environmental Readiness Division and subsequently by the US Navy’s Living Marine Resources (LMR) Program. Additional support for environmental sampling and logistics was also provided by the Office of Naval Research, Marine Mammal Program. The effect of active sonars on marine mammal behavior is a topic of considerable interest and scientific investigation. Some whales, including the largest species (blue whales, Balaenoptera musculus), can be impacted by mid-frequency (1-10 kHz) military sonars. Here we apply complementary experimental methods to provide the first experimentally controlled measurements of behavioral responses to military sonar and similar stimuli for a related endangered species, fin whales (Balaenoptera physalus). Analytical methods include: (1) Principal Component Analysis paired with Generalized Additive Mixed Models; (2) Hidden Markov Models; and (3) structured expert elicitation using response severity metrics. These approaches provide complementary perspectives on the nature of potential changes within and across individuals. Behavioral changes were detected in five of 15 whales during controlled exposure experiments (CEEs) using mid-frequency active sonar (MFAS) or pseudorandom noise (PRN) of similar frequency, duration, and source and received level. No changes were detected during six control (no noise) sequences. Overall responses were more limited in occurrence, severity, and duration than in blue whales and were less dependent upon contextual aspects of exposure and more contingent upon exposure received level. Quantifying the factors influencing marine mammal responses to sonar is critical in assessing and mitigating future impacts. Peer reviewed