LIKE PARTYGOERS SHOUTING to be heard over the din of a crowded room, orcas in Puget Sound are shouting their conversations, says Marla Holt, a National Oceanic and Atmospheric Administration biologist.

Salmon fishing boats, container ships, pleasure craft—up to 46 vessels per 1,094—yard radius in the Sound—contribute to 123 underwater decibels. To cut through the racket, according to a study Holt released earlier this year, our finned neighbors must yell their distinct wails, which they use to chat while hunting and to zero in on food via echolocation. (Specifically, they raise their voices one decibel for every decibel of boat noise.)

But there’s more at stake than a more raucous whale pod. The orcas’ prey of choice, chinook salmon, is disappearing. “If the whales are already having a hard time finding food,” says Holt, “and they’re using sonar to find food, what effect does traffic noise have on their ability to do so?”

Seven members of the local orca population have disappeared within the past year and are likely dead. While it’s uncertain whether vessel clamor contributed to the whales’ fate, NOAA–responding to Holt’s findings and other studies—has proposed federal legislation that would restrict vessels from traveling within 200 yards of orcas.

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