ISLE OF PALMS, S.C. (AP) — A rare 475-pound endangered leatherback sea turtle found stranded on a South Carolina beach was released into the ocean on Thursday following five days of treatment at the South Carolina Aquarium.

The turtle, named Yawkey and the first leatherback known to have stranded alive in the state, was carried in a box to the edge of the surf on a wind-swept beach at the Isle of Palms near Charleston.

Staffers from the aquarium and the state Department of Natural Resources lowered the sides of the box and, after a minute or two of hesitation, the turtle made its way into the surf as a crowd of about 75 people cheered.

For about 10 minutes, Yawkey then swam parallel to the shore — aquarium workers said the creature was hung up on a sand bar — before a large wave came in, the turtle raised a large flipper above the surface and then disappeared.

The turtle was found Saturday in Georgetown County on a beach at the Yawkey-South Island Reserve — hence the turtle's name — and brought to the aquarium where it was treated with antibiotics and fluids and made a quick recovery.

"It couldn't have gone any better from the time she came to us through release. We're extremely happy," said Kelly Thorvalson, program manager for the aquarium sea-turtle rescue program.

It is not known exactly what was ailing Yawkey, but Thorvalson said the turtle may have eaten some plastic it mistook for a jellyfish, which is the leatherback's favorite food. That could have caused a buildup of gas in the digestive tract making the turtle buoyant and washing it to shore.

Leatherbacks, an endangered species, are the largest sea turtles, with adults generally weighing 800 to 1,000 pounds. They get their name because, instead of a shell, their backs are covered with leathery, oily tissue.

While the turtle's weight was estimated at 500 pounds when it was rescued, it weighed in at 475 pounds Tuesday, said Kate Dittloff, the aquarium public relations manager.

Thorvalson said it was important to get Yawkey back to the ocean quickly because leatherbacks don't do well in captivity. Because they live in deep water, they don't sense boundaries so they tend to swim into the sides of tanks and bruise.

Jenna Cormany, a wildlife biologist with the South Carolina Department of Natural Resources, was pleased that Yawkey had recovered.

"We enjoyed her stay, but we would prefer it if she didn't come back," she said, laughing.