A new addition for Discovery Cove: a saltwater environment dubbed "Grand Reef"

It marks the first significant expansion of Discovery Cove, the 10-year-old boutique park that has carved a unique niche in Orlando's theme-park industry. While the area's larger theme parks depend on huge volumes of visitors buying tickets, food and souvenirs every day, Discovery Cove caps its daily attendance at about 1,000 people, which allows it to offer resort-style pampering and personalized encounters with animals — and to command much higher ticket prices than those for a typical theme park.

SeaWorld says Discovery Cove has cultivated a loyal following since opening in 2000, and the expansion is designed to ensure that return visits continue.

"As we get so many repeat visitors, this will give them something new," said Stewart Clark, the SeaWorld vice president in charge of Discovery Cove.

The 2.5-acre Grand Reef, to open next June, will be a lush tropical environment with a white-sand beach, underwater grottoes and a palm-tree-lined island. It will be built around an aquarium filled with more than 1 million gallons of water and 125 species of fish, rays and sharks.

Guests will be able to wade and snorkel with tropical fish, cross a rope bridge over a shark-filled lagoon, and relax in island hammocks. But the most interesting addition will be an underwater walking tour dubbed "SeaVenture," in which guests will don dive helmets and follow a submerged path, roughly 10 feet below the surface, that will take them through schools of tropical fish and past venomous lion fish and sharks that can be viewed through panoramic windows.

That limited-capacity experience, which will cost an additional $59 on top of Discovery Cove's base admission price, will last about an hour and accommodate as many as six people at a time. Clark said some details are still being worked out, such as age limits and when the park will begin accepting reservations.

Clark said Grand Reef will feature improvements over Discovery Cove's existing reef. For example, the layout will allow people who are only able to wade in shallow water to see many of the same sights witnessed by guests snorkeling in deeper water. There will be less underwater sand, to reduce instances where silt is kicked up and impedes visibility. And Grand Reef will incorporate several new species of fish, including moray eels and reef sharks.

The existing reef will close once Grand Reef opens. Clark said Discovery Cove will build a new feature in its place, to debut in 2012, though he would not discuss specifics.