Maine game wardens are looking for an Oregon man who is suspected to have drowned on Swan Lake in Swanville.

The Maine Warden Service said Christopher N. Friedrich, 41, of Springfield, Oregon, was reported missing Tuesday afternoon and a local camp owner told game wardens that he had seen an upturned kayak and some personal items floating on the lake Sunday morning.

The kayak was later traced to Friedrich, who last had contact with family members Saturday evening, and Friedrich’s vehicle was located at the Swanville Boat Launch.

A warden service dive team on Wednesday was searching an area about a half mile north of the boat launch and wardens were also using side-scan sonar to search the lake.

There have been an increase in drownings or near-drownings in Maine rivers and lakes over the last week. Authorities said many people may have decided to go swimming during the recent heat wave, but tired quickly in the rivers and lakes, most of which are still very cold.

On Sunday, a man drowned in the Saco River in Buxton and on Monday two men drowned in Messalonskee Lake after wind pushed away the pontoon boat from which they’d jumped. Also, on Monday, a 13-year-old girl was rescued from the Cherry Pond area of the Androscoggin River in Greene but died a day later. On Tuesday, the body of a fisherman who apparently fell off his skiff was recovered from the Medomak River in Waldoboro.