Why Do Beaked Whales Return to a Navy Sonar Range Despite Frequent Disturbance? It’s the Food.

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Using data from underwater robots, scientists have discovered that beaked whales prefer to feed within parts of a Navy sonar test range off Southern California that have dense patches of deep-sea squid.

Using data from underwater robots, scientists have discovered that beaked whales prefer to feed within parts of a Navy sonar test range off Southern California that have dense patches of deep-sea squid. A new study published in the Journal of Applied Ecology, shows that beaked whales need these prey hotspots to survive, and that similar patches do not exist in nearby “sonar-free” areas.

For decades, the U.S. Navy has used high-powered sonar during anti-submarine training and testing exercises in various ocean habitats, including the San Nicolas Basin off Southern California. Beaked whales are particularly sensitive to these kinds of military sonars, which sometimes result in mass stranding events. Following legal action from environmental activists related to these risks, the Navy modified some training activities, created “sonar-free” areas, and spent more than a decade and tens of millions of dollars trying to find ways to reduce the harm to beaked whales and other mammals.

The new research, led by Brandon Southall at the University of California, Santa Cruz, and Kelly Benoit-Bird at the Monterey Bay Aquarium Research Institute, aimed to better understand why whales keep returning to the test range despite the risks.

Read more at Monterey Bay Aquarium Research Institute

Image: A Cuvier’s beaked whale on the Navy sonar range off California.  CREDIT: A. Friedlaender; NMFS permit #14534