Some blue whales off the coast of California change their behavior when exposed to the sort of underwater sounds used during U.S. military exercises.
The whales may alter diving behavior or temporarily avoid important feeding areas, according to new research.
The Southern California Behavioral Response Study exposed tagged blue whales in the California Bight to simulated mid-frequency (3.5-4 kHz) sonar sounds significantly less intense than the military uses.
“Whales clearly respond in some conditions by modifying diving behavior and temporarily avoiding areas where sounds were produced,” said lead author Jeremy Goldbogen of Cascadia Research. “But overall the responses are complex and depend on a number of interacting factors,” including whether the whales were feeding deep, shallow or not at all.