Invasive zebra mussels are threatening an underwater historic preserve in Lake Champlain.
The preserve maintained by the Lake Champlain Maritime Museum is made up of nine Vermont vessels and one New York vessel, all of which can be explored by divers.
They include tug boats and canal boats.
Archaeologist Chris Sabick said that the stories behind the boats may be all that's left one day because of damage caused by the zebra mussels. He said thousands of mussels are attached to the vessels, putting a strain on the water-logged, wooden decks.
Steve Smith is a marine life expert at the ECHO Center for Lake Champlain. He said the colonies can be 2 to 3 inches thick. He said they can degrade iron, in addition to wood.