title: Blue whales respond to simulated mid-frequency military sonar.
abstract: Mid-frequency military (1-10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health.
authors.affiliation: Cascadia Research Collective, 218 1/2 W. 4th Avenue, Olympia, WA 98501, USA. brandon.southall@sea-inc.net
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Goldbogen
authors.forename: Brandon L
authors.initials: BL
authors.lastname: Southall
authors.forename: Stacy L
authors.initials: SL
authors.lastname: DeRuiter
authors.forename: John
authors.initials: J
authors.lastname: Calambokidis
authors.forename: Ari S
authors.initials: AS
authors.lastname: Friedlaender
authors.forename: Elliott L
authors.initials: EL
authors.lastname: Hazen
authors.forename: Erin A
authors.initials: EA
authors.lastname: Falcone
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Schorr
authors.forename: Annie
authors.initials: A
authors.lastname: Douglas
authors.forename: David J
authors.initials: DJ
authors.lastname: Moretti
authors.forename: Chris
authors.initials: C
authors.lastname: Kyburg
authors.forename: Megan F
authors.initials: MF
authors.lastname: McKenna
authors.forename: Peter L
authors.initials: PL
authors.lastname: Tyack
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D050616:Balaenoptera / Q000502:physiology*; D002140:California; D005247:Feeding Behavior / Q000502:physiology; D008889:Military Personnel; D013016:Sound; D013550:Swimming
keywords: bio-logging; blue whale; foraging; military sonar; sensory ecology; underwater noise