JONESPORT, Maine — U.S. Coast Guard officials are investigating why a 35-foot lobster boat sank overnight Monday near the Jonesport Bridge.

Lt. Scott McCann said the owner of the boat contacted the Coast Guard Tuesday morning to say the boat had been on its moorings Monday night but was underwater by morning.

“We don’t know why it happened,” McCann said shortly before noon Tuesday. “We’ll be investigating the cause.”

The owner, whose name was unavailable, planned to salvage the boat, the Riley Anna, later in the day Tuesday, McCann said.

Because the owner reported the incident, the Coast Guard did not have to perform a search and rescue. However, the Coast Guard reported the situation to the Maine Department of Environmental Protection because the owner said he had 50 gallons of diesel on board, McCann said.

“We have a team out there right now to do what we can to mitigate,” he said.

So far, he said, no pollution has been reported.