Protecting Ocean Sound and Food for the Future of Orcas



Many different marine species are affected by noise pollution, but orcas are particularly at risk because the rely on sound. Although they’re called killer whales, orcas are related to dolphins. They’re highly social mammals that live in maternal pods and hunt cooperatively. Each pod in the Northern Pacific has its own dialect and communicates through a series of whistles, clicks and pulses.

Because light doesn’t go far underwater, orcas also rely on sound to locate prey. Pods use echolocation to find and round up their food together. Scientists have realized that these mammals even use sound to discern different species of prey. For example, Southern Resident killer whales specifically seek Chinook salmon.

Research shows that intense sounds can disorient marine mammals like orcas, causing abnormal behavior. For example, after the navy started using high-power sonar, there was a spike in the number of beached whales – 126 were reported from 1950-2004.

Underwater, the sounds caused by ships falls directly into the frequencies orcas use to hear and communicate. This constant background noise puts pressure on an already stressed animal – several species of killer whales are already endangered because of pollution, overfishing and loss of habitat.


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