Like viewers worldwide, Fabien Cousteau was entranced by his famous grandfather’s films about marine life and human exploration underwater. Now he’s adding to his family’s sea stories with a 31-day underwater expedition in the Florida Keys.

Cousteau is set to dive Sunday to Aquarius Reef Base, a school bus-sized laboratory 60 feet below the ocean’s surface, a few miles off Key Largo. He plans to spend more than a month living underwater with a five-person crew, making a documentary and leading science experiments on the nearby coral reef.

The idea for “Mission 31” came to Cousteau two years ago when he visited Aquarius during a fundraising push to save the lab, which federal budget cuts had threatened to permanently close.

“It reminded me that I’ve always wanted to live underwater,” Cousteau said Saturday at his training base in Islamorada.

“Mission 31” builds on the legacy of Conshelf II, the 30-day underwater living experiment in the Red Sea that Jacques Cousteau filmed in 1963 for his Oscar-winning documentary “World Without Sun.”

The younger Cousteau can do something his grandfather could not: broadcast the entire adventure live online and communicate with the public through social media and video chats with classrooms on land.