The Coast Guard and Maine Marine Patrol said today they are investigating a growing number of missing metal sound signals from buoys along the Maine coast.

At least seven buoys have had their bells and gongs removed. Investigators suspect they are being sold, possibly to nautical shops or scrap metal yards.

Chief Warrant Officer Jeffrey Chase said an individual bell can cost taxpayers between $400 and $1,500 to replace.

Officials say theft of the bell is akin to stealing a traffic light on a busy street. The bells serve as warnings to mariners of hazards.

Anyone with information concerning the thefts should contact the nearest Coast Guard station or make an anonymous report to the Maritime Safety Inspection hotline at 1-800-682-1796.