According to a NOAA-led paper published today in the journal Conservation Biology, high levels of background noise, mainly due to ships, have reduced the ability of critically endangered North Atlantic right whales to communicate with each other by about two-thirds.
From 2007 until 2010, scientists from Stellwagen Bank National Marine Sanctuary, Cornell Lab of Ornithology, NOAA Fisheries Northeast Fisheries Science Center, and Marine Acoustics Inc. used an array of acoustic recorders to monitor noise levels, measure levels of sound associated with vessels, and to record distinctive sounds made by multiple species of endangered baleen whales, including "up-calls" made by right whales to maintain contact with each other.
NOAA Fisheries Northeast Fisheries Science Center documented more than 22,000 right whale contact calls as part of the study during April 2008, and software developed by Cornell and Marine Acoustics Inc. of Arlington, Va., aided in modeling ship noise propagation throughout the study area.
Vessel-tracking data from the U.S. Coast Guard's Automatic Identification System was used to calculate noise from vessels inside and outside the sanctuary. By further comparing noise levels from commercial ships today with historically lower noise conditions nearly a half-century ago, the authors estimate that right whales have lost, on average, 63 to 67 percent of their communication space in the sanctuary and surrounding waters.
"A good analogy would be a visually impaired person, who relies on hearing to move safely within their community, which is located near a noisy airport," said Leila Hatch, Ph.D., NOAA's Stellwagen Bank National Marine Sanctuary marine ecologist and lead author of the paper. "Large whales, such as right whales, rely on their ability to hear far more than their ability to see. Chronic noise is likely reducing their opportunities to gather and share vital information that helps them find food
|Contact: Keeley Belva|