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/ .
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).
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).
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).
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).