What led to the sinking of an out-of-service tugboat north of Sitka last week remained unknown Sunday, according to the U.S. Coast Guard.
"There will probably be no determination until it's raised out of the water," Lt. Jennifer Ferreira, a public affairs officer with Coast Guard Sector Juneau, said Sunday.
The 81-foot tug Powhatan had been out of service for more than a decade when it sank Wednesday night at the Samson Tug and Barge pier about 7 miles north of Sitka, according to a Coast Guard statement.
Samson Tug and Barge, an Alaska-owned interstate shipping company, owns the Powhatan and reported that the tug had about 325 gallons of lube oil and 12 gallons of diesel on board, according to the Alaska Department of Environmental Conservation's Friday situation report on the sinking.
DEC staff and the Coast Guard Marine Safety Detachment Sitka responded to the sunken tug, which sat in about 200 feet of water in Starrigavan Bay, said the DEC report.
The tug's owner contracted with Southeast Alaska Petroleum Response Organization to recover oil, conduct shoreline assessment and maintain boom — floating barriers to contain oil spills. It also contracted with Hanson Maritime to dive and survey the tug, the Coast Guard said.
Ferreira said some residual diesel fuel and oil leaked from the sunken tug. By Sunday, she said, "there may still be a pretty minor leak, but they think most of it has come out."
The DEC said in its report that herring larvae and salmon fry may be in the area of the sinking.
"There is the potential for exposure to marine wildlife (i.e. sea otters and birds) but there have been no reports of impacts to, or observations of, any in the immediate area," the report said.
It said the Alaska Department of Fish and Game had provided "recommended priorities for protection."
Alaska DEC and Samson Tug and Barge did not respond to a request for comment Sunday. Ferreira said the company planned to have the tug removed.