Churaumi Aquarium: Okinawa's riveting sea show

Scores of silhouettes stand in the blue glow of the Kuroshio Sea Tank, only 60 centimeters of acrylic separating them from a mini-ocean filled with creatures great and small.Smartphones gleam like beacons in the dark, cavernous room, on standby to capture photos once the show starts.A woman appears on a screen that hangs next to the tank.

“Mina-san, hi, hi,” she says in Japanese, welcoming everyone. She’s behind the scenes, perched above the water and gearing up for feeding time.

Three whale sharks glide back and forth in the 7,500-square-meter tank as manta rays, nurse sharks and all manner of fish -- giant grouper, yellowfin tuna, yellow and blueback fusilier -- weave around them. The announcer provides more commentary (in Japanese) before staff start dumping plankton and shrimp into the tank by the bucketful.The whale sharks open their mammoth mouths and keep on swimming.

“It's eating, look it's eating,” I hear one man say to the little girl who’s sitting on his shoulders. “That's a big fish.”

Whale sharks are, in fact, the biggest fish in the world. But they’re filter feeders, so watching them chow down is about as exciting as watching a plant suck in carbon dioxide. Still, seeing them do anything in this kind of setting is considered a rare treat.

The experts at the Okinawa Churaumi Aquarium say captive reproduction “has been fraught with difficulties” and that they're the only ones on the planet to house multiple whale sharks in a tank.The oldest, which is about 17, came to the aquarium years ago after fishermen caught it in a net. It now measures 8.5 meters long and weighs 5.5 tons.

“I’ve been to quite a few aquariums in different cities, but never seen a whale shark in an aquarium,” says Tracy Ruggiero, a tourist from Hawaii. “It’s beautiful.”