5 a.m., April 16
Human Generated Noise Potentially Harmful to Endangered Blue Whales
The Scripps Institute of Oceanography at UC San Diego has published a report on the effect of human-created underwater noise on whales, Scientific American reports.
The paper is the latest examining the effects of sonar, engine noise from passing ships, and underwater explosions on the communication patterns of marine mammals, particularly the endangered blue whales that pass the San Diego coast during their annual migration.
In analyzing over 4,600 hours of data, researchers studied whale reactions to low-frequency “D-calls,” which are emitted by blue whales in what is believed to be a means of communication concerning the presence and location of food sources. While these calls were picked up 48% of the time, 9% of whales’ reactions were to sonar soundings.
While typically outside the range of sounds put off by baleen whales, the family to which blue whales belong, the sonar pitch includes a range used by killer whales, which frequently prey on blues. As a result, miscues involving blue whales’ reaction to sonar could end up guiding them into peril.
“We become frustrated when poor cell service results in dropped calls on our mobile phones,” says Scientific American. “Imagine if a noisy environment not only resulted in less efficiency in finding dinner, but also in the increased likelihood of becoming someone else’s dinner! This is the reality in which blue whales live, thanks to human intrusion into the marine soundscape.”
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