Two endangered Southern Resident killer whales rise in unison from the Salish Sea as a tanker passes through their habitat. (Image credit: beamreach.org)
New findings suggest noise from ships overlaps frequencies used for communication and foraging by orcas, potentially affecting the endangered Southern Resident orcas living in the waters around Vancouver Island, B.C.
The researchers found container ships created the highest levels of background noise at frequencies below 20,000 Hz, and military vessels typically had some of the lowest levels. However all ships created noise above 20,000 Hz, the range at which killer whales hear best, creating the potential to interfere with both communication and echolocation, used for navigation and hunting.
Original research paper published in PeerJ on February 2, 2015.
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