Incredibly rare 'megapod' of more than 100 humpback whales surrounds boat off coast of Australia

A "megapod" of more than 100 humpback whales has been filmed surrounding a boat off the coast of Australia -- an incredibly rare event an expert says has only ever been captured once before in the country's waters.

The whales skirted the boat near Bermagui, about 236 miles (380 kilometers) from Sydney, in the state of New South Wales, as they fed on a large bait ball -- a tightly packed school of fish swimming in a spherical shape. Simon Millar, owner of Sapphire Coastal Adventures, was leading a team training exercise with his staff when they spotted the whales on September 9. In the video, the whales can be seen slapping their tails in the ocean, trying to herd the fish.