Good news for cetaceans: nets no longer have to be invisible to sonar
They were originally used to mark mined areas so ships wouldn’t blunder into them, but they don’t look too expensive so I guess they figured they could use them to save the whales. They also have no complicated electronics and require no power, so they’re easy to maintain. Double grog ration for the guy who came up with these things.
Military beacons to aid sea life [BBC News]