A kayak with no one in it was found drifting 900 yards east of Plum Island Tuesday, launching a multiagency search by air and water for a missing person, authorities said.

Someone on a fishing vessel spotted the kayak on the Long Island Soundearly Tuesday, Southold Town Police Chief Martin Flatley said.

"They found a kayak with belongings inside it," he said.

Coast Guard photos show a red, one-person kayak with fishing rods and a net. There also was food inside, officials said.

The Coast Guard said the overturned kayak was reported by a Good Samaritan at 3:20 p.m.

For hours, the Coast Guard searched with a 47-foot vessel from the Montauk station and a helicopter, along with town police marine units and a Suffolk police helicopter.

Searchers were scouring the waters 121/2 miles east and west of Plum Island, Coast Guard Petty Officer Timothy Halverson said.

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No kayaker has been reported missing, said Cmdr. Andrew Ely, chief of response for Coast Guard Sector Long Island Sound, based in New Haven, Connecticut.

Coast Guard officials said they will likely keep searching by helicopter and boat through the night and into the morning.

"There are signs which point to the vessel being operated and not just washing off with the tide, which is a matter for concern," Ely said. "If we can identify any characteristics about the user or fill in any timeline details, it can greatly assist us in narrowing our search to the most likely areas."

The watercraft was identified as a 12-foot Pelican kayak with a hull identification number of CAZEP10662D515.

Flatley said there was no indication how long the kayak had been adrift, but he expected it was not for weeks and months, because fishing boats and ferries in the area would probably have spotted it.

The Coast Guard asks anyone with information to call them at 203-468-4444.