Vocal communication in blue whales (Balaenoptera musculus) and noise interference

• Main Author: Di Iorio, Lucia
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2009
• Subjects: Institute of Evolutionary Biology and Environmental Studies; UZH Dissertations; 570 Life sciences; biology; 590 Animals (Zoology); Balaenoptera musculus; Blue whale; North Atlantic
• Online Access: https://www.zora.uzh.ch/id/eprint/30004/; https://www.zora.uzh.ch/id/eprint/30004/9/Di_Iorio_Diss_2009_V.pdf; https://doi.org/10.5167/uzh-30004

Long-range acoustic communication represents one of the main modalities to transmit information and maintain social relationships among distant individuals. By examining variation in long-range signals, we can gain insights into their function as well as the processes underlying the variation. Since communication and social behaviour are tightly linked, variation in acoustic signals can reflect behavioural patterns that are important to better understand the sociobiology of a species. Moreover, changes in vocal behaviour can also be induced by factors interfering with acoustic communication, such as anthropogenic noise. In my thesis, I investigated patterns of variability in the long-range male vocal displays (‘songs’) of North Atlantic blue whales (Balaenoptera musculus) at the level of the population, the individual, as well as in relation to the social and behavioural context. I also examined whether seismic noise affected the production of blue whale ‘calls’, transient discrete vocalisations used by both sexes in short-range social contexts. Blue whales are invaluable for the study of variation in long-range signals because they live in a highly fluid social environment, and their songs - redundant, patterned sequences of infrasonic sounds - can be heard over hundreds of kilometres. I collected simultaneous behavioural observations and acoustic recordings in the field and analysed the temporal and acoustic structure of blue whale songs. I found that multiple features differed between the songs of blue whales from the eastern and western North Atlantic. It is thought that due to the extensive singing during their basin-wide roaming, blue whales throughout the North Atlantic may be physically and/or acoustically sympatric. The song divergence found here was likely dependent on ecological factors, but could also have been driven by mate choice. In fact, songs are thought to be male reproductive displays, suggesting that female preferences for specific traits could have accounted for the observed differences. ...