Cars line up daily for the 8 a.m. opening of Honeymoon Island State Park.

Sunbathers? Hardly. Many are shell collectors looking for treasures the Gulf of Mexico might have tossed ashore overnight.

Even Christmas morning there were a dozen or so locals and tourists braving a stiff wind and 50-degree temperatures to patrol the island's rocky north shore.

That's where the best shelling is, park rangers say.

A good score along the rocks might be a perfect sand dollar or perhaps a two-foot horse conch shell, which can fetch more than $100 from a true collector or wholesaler, according to Florida Fabulous Sea Shells, a reference book in the park's library.

On Saturday, small fighting conch and horse conch shells, with their shiny dark orange tones, were seemingly everywhere. But nearly all those inspected had the conch still inside the shell.

And that means they must stay on the beach. Live shelling -- removing a shell with an animal in it -- is unlawful. Signs around the island remind visitors.

Thomas Kennedy, of Clearwater, was there Saturday searching for big shells. The huge orange bucket by his side was a clue he wasn't looking for something to place in a curio cabinet.

"The other day some guys got some huge shells. That's what I want," Kennedy said. "Every day is a new day. You never know what you'll come across. The tides and the winds have a lot to do with it."

Visiting Dunedin from Indiana, Gene Kowalski, 63, said she has an annual Christmas morning tradition of walking the north shore for an hour in search of shells to take home and share with relatives.

"But I don't walk on the rocks. I'm not that brave and Christmas is not the day I want to go to the emergency room," Kowalski joked. "There's enough for me in safer spots."

Kowalski showed off two halves of a sand-covered pen shell she discovered. Roughly eight inches long, the insides of these spiny black shells have a mother of pearl coating. According to a shell guide along the beach, the iridescent finish is the same substance found in pearls.

Thirty-three types of shells are shown on the beachfront shelling guide.

For those who want an education before braving the sand and rocks, the park's Rotary Centennial Nature Center shows a shelling video in a presentation room and has nearly every shell -- plus starfish and sponges -- available to examine.

Volunteers host an educational shell presentation for all ages at the center every third Saturday from 1:30 p.m. to 4:00 p.m. Only park admission is required.