Meanwhile, on the ocean floor…

The Global Web of Subsea Cables That Connects the World Can Now Detect Whales—Even When They're Silent smithsonianmag.com

The fiber-optic cables that carry the internet across ocean basins turn out to double as whale detectors: a diving whale's body pushes a pressure wave that registers as a faint strain in the glass. That means silent, non-vocalizing cetaceans can be tracked using infrastructure already lying on the seabed, with no new instruments dropped in the water.