New maps show high-risk zones for whale-ship collisions—vessel speed limits and rerouting can reduce the toll

Imagine you are a blue whale swimming up the California coast, as you do every spring. You are searching for krill in the Santa Barbara Channel, a zone that teems with fish, kelp forests, seagrass beds and other undersea life, but also vibrates with noise from ship traffic. Suddenly, the noise gets louder.