Watch and listen: Humpback whales sing in the background on snorkeling visit with green turtles

I have an odd hobby: collecting whale sounds with a hydrophone. It began when I bought one of the devices in 2004 so I could listen in on killer whales. Since then, I’ve gathered a nice collection of both Northern and Southern Resident orcas, as well as humpback whale sounds in various locations, and even sperm-whale echolocation in New Zealand.

But in February 2017, I managed to collect humpback whale sounds without a hydrophone—and quite accidentally. It happened in Maui during a snorkeling trip to swim with the green turtles that are populous there on the island’s southwestern shore. I thought I was hearing whalesong while underwater—and sure enough, I had.