Short- and long-term changes in right whale calling behavior: The potential effects of noise on acoustic communication

• Published in: The Journal of the Acoustical Society of America Vol. 122; no. 6; pp. 3725 - 3731
• Main Authors: Parks, Susan E., Clark, C. W., Tyack, P. L.
• Format: Journal Article
• Language: English
• Published: Woodbury, NY Acoustical Society of America 01-12-2007; American Institute of Physics
• Subjects: Acoustics; Adaptation, Physiological; Animals; Canada; Echolocation; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Noise, Transportation - adverse effects; Perceptual Masking; Physics; Ships; Signal Processing, Computer-Assisted; Sound Spectrography; Time Factors; Underwater sound; Vocalization, Animal; Whales - physiology; Canada; Marine animal; Short term; Vertebrata; Mammalia; Whale; Cetacea; Background noise; Underwater acoustics
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.2799904

The impact of anthropogenic noise on marine mammals has been an area of increasing concern over the past two decades. Most low-frequency anthropogenic noise in the ocean comes from commercial shipping which has contributed to an increase in ocean background noise over the past 150 years. The long-term impacts of these changes on marine mammals are not well understood. This paper describes both short- and long-term behavioral changes in calls produced by the endangered North Atlantic right whale (
Eubalaena glacialis
) and South Atlantic right whale (
Eubalaena australis
) in the presence of increased low-frequency noise. Right whales produce calls with a higher average fundamental frequency and they call at a lower rate in high noise conditions, possibly in response to masking from low-frequency noise. The long-term changes have occurred within the known lifespan of individual whales, indicating that a behavioral change, rather than selective pressure, has resulted in the observed differences. This study provides evidence of a behavioral change in sound production of right whales that is correlated with increased noise levels and indicates that right whales may shift call frequency to compensate for increased band-limited background noise.