Listening to Whale Songs!

by Kara Aschenbrenner

Hydrophone data of orcas, humpback whales and Pacific white-sided dolphin vocalizations can be accessed from www.neptunecanada.com/news/sound-gallery/ or venus.uvic.ca/multimedia-features/hydrophone-highlights/whale-sounds/ .

Orcas. Photo Credit: Francine Mercier, Parks Canada (accessed from: http://www.dfo-mpo.gc.ca/oceans/publications/fedmpa-zpmfed/page01-eng.asp ). The Strait of Georgia is one of the busiest waterways for shipping vessels in Canada and the impacts on killer whales from the underwater noise pollution are of major concern.

Hydrophones (underwater microphones) installed in Folger Passage and the Strait of Georgia, part of the NEPTUNE Canada and VENUS networks, record vocalizations produced by cetaceans. These hydrophone recordings include the songs of transient and resident killer whale pods, humpback whales, fin whales and Pacific white-sided dolphins. The recordings provide scientists with important information about behavior, seasonal migrations, and population shifts (NEPTUNE Canada, 2012).

Pacific white-sided dolphin spotted from the R/V Thompson off of the west coast of Vancouver Island during a cruise for NEPTUNE Canada. Photo credit: NEPTUNE Canada. (Accessed Nov 13, 2012, at neptunecanada.ca/news/news-details.dot?id=35733)

Cetaceans are highly dependent on acoustics as a means of social communication and finding food (echolocation). This is because light can only travel short distances, ~5–20 meters in the water, whereas sound can travel an astonishing 1000 km (VENUS, 2012)! Therefore, the increase in background noise produced by overpassing shipping vessels is a major concern.  Possible impacts to whales from underwater noise exposure include  disturbance and masking of important sounds and hearing damage (Cato et al, 2004).

Spectrogram produced from the VENUS hydrophone array located at the Strait of Georgia East site (170 m depth). Whale sounds are heard during this hydrophone recording. Credit: VENUS Network. (Accessed Nov 13, 2012, at venus.uvic.ca/multimedia-features/hydrophone-highlights/whale-sounds/)

Different cetaceans produce a wide range of unique songs which can be heard with hydrophone recordings. Sounds can be described as whistles, clicks, groans, moans, squeaks and even barks (Seaworld, 2012). For example, dolphins generally sound chatty and produce clicking noises, whereas fin whales have low frequency calls (NEPTUNE Canada, 2012). Songs can also vary between different whale populations depending on which ocean basin they live in (Cato et al, 2000).

References

NEPTUNE Canada (2012). NEPTUNE Canada: An Invitation to Science. Victoria, B.C: University of Victoria.

NEPTUNE Canada, 2012. Website. Accessed Nov.12, 2012: www.neptunecanada.ca/

VENUS, 2012. Website. Accessed Nov. 12, 2012: www.venus.uvic.ca/

Cato, D.H., McCauley, R.D. and Noad, M.J. 2004. Potential effects of noise from human activities on marine animals. Proceedings of Acoustics 2004, Australian Acoustical Society Conference, Gold Coast, 3-5 November. Pp 369-74

Noad, M.J., Cato, D. H., Bryden, M.M. , Jenner, M-N. and Jenner, K.C.S. 2000. Cultural revolution in whale songs. Nature 408 (6812): 537.

Killer Whales. www.seaworld.org/animal-info/info-books/killer-whale/communication.htm. (Accessed Nov 14, 2012).