ORLANDO, Fla. — Some of SeaWorld Orlando's most innovative science is happening inside its most popular thrill ride.

Just out of sight of visitors, at the surface of the aquariums used in the guest queue for the Manta roller coaster, about 40 weedy-sea-dragon hatchlings are floating in a complicated network of tanks, suspended in a gentle, counterclockwise current.

SeaWorld is the fourth aquarium in the United States — the sixth in the world — to successfully breed sea dragons, which are rare relatives of sea horses that in the wild are found only off the southern and eastern coasts of Australia. Although the babies look like little more than tiny tree twigs now, they will eventually grow to as much as 18 inches in length.

The nonprofit Monterey Bay Aquarium in California announced its first successful hatching of weedy sea dragons at just about the same time.

For Orlando-based SeaWorld Parks & Entertainment, the hatchlings are a vivid example of the type of animal research and conservation work that executives insist is a part of the company's corporate DNA.

But it is about much more than altruism. Investing in such work is critical for the company to maintain its standing with guests, many of whom are uneasy about it keeping animals in captivity — particularly large, sophisticated creatures such as SeaWorld's killer whales.

Dueling polls released last month illustrate that ambivalence. One survey, paid for by several animal-rights groups, found that 24 percent of people strongly oppose keeping killer whales in captivity — triple the number of people who said they strongly support the practice. But another, paid for by the SeaWorld-backed Alliance of Marine Mammal Parks & Aquariums, found that 91 percent of people agree marine parks are important in promoting environmental conservation.

About 23.6 million people visited SeaWorld Parks & Entertainment's 10 U.S. parks last year, generating more than $1.3 billion in sales.

"We see people come up to this (sea-dragon) exhibit every day, and they're just amazed to see that there's something so unusual-looking. They're a beautiful representation of the marine life of the ocean," said Teryl Nolan Hesse, assistant curator for aquariums at SeaWorld Orlando. "They come here, see this, and they get excited about it. And when they're excited about something, they want to learn more."

There are two types of sea dragons: weedy and leafy. The leafy sea dragons have more foliagelike camouflage on their limbs and are even rarer than their weedy counterparts. SeaWorld has five adult weedies in its collection and two leafies.

They are finicky creatures. They are extremely sensitive to light and must be watched whenever they are fed — they get tiny mysid shrimp three times a day — to ensure they are eating, rather than lunging at their food but missing.

For more than a decade, SeaWorld kept all of its sea dragons in a 5-foot-tall aquarium in Shark Encounter that had once been home to various types of fish. But the park was never able to breed them.

SeaWorld's aquarists had a theory for why: Their aquarium was too short. When sea dragons mate, they engage in a kind of "courtship dance," in which the male and female slowly spiral upward together. SeaWorld's sea dragons kept reaching the surface too quickly.

In the decision to build Manta — a combination inverted roller coaster and walk-through aquarium that opened in 2009 — SeaWorld's aquarium team decided to build a new, custom-designed home for the sea dragons.

The Manta aquarium is 11 feet tall, more than twice as high as the Shark Encounter aquarium. It also has separate chambers to keep the leafy sea dragons apart from the weedy ones, reducing the odds that one animal will bump into a pair doing a mating dance.

The new sea-dragon habitat is hooked to a lighting system that slowly dims at night and gradually illuminates in the morning, mimicking sunsets and sunrises. It has its own water-filtration system, and the water temperature is kept in the mid-50s.

Out of sight of guests, SeaWorld erected a separate, refrigerator-size aquarium, to which it moved its pregnant male once it became clear that hatchlings were imminent.

That aquarium has a false bottom to catch tumbling hatchlings, which can then be moved to a network of even-smaller aquariums supercharged with nutrients and maintained with a constant, though minimal, current.

The successful hatching came late last month.

SeaWorld faces another challenge with its sea dragons: breeding the leafy ones.

No facility has successfully bred leafy sea dragons.