According to a NOAA-led paper published 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 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.

The study authors estimate that right whales have lost, on average, 63% to 67% of their communication space in the sanctuary and surrounding waters.