Buoys Help Avert Whale-Ship Collisions : Image

An auto-detection whale buoy is deployed off Boston. The surface buoy at right remains above the waves. An anchor will pull the subsurface flotation sphere (left) down to 10 to 20 meters beneath the surface, where it will hold up a lower mooring line that holds a hydrophone to record sounds in the ocean, including whale calls. (Matthew Barton, Woods Hole Oceanographic Institution)