A derelict Japanese ship dislodged by last year’s massive tsunami was drifting toward Alaska, the US Coast Guard said.

The shrimping vessel was floating slowly northwest in the Gulf of Alaska about 201 kilometres west of the nearest point of land Forrester Island outside the Dixon Entrance, a maritime transportation corridor separating US and Canada jurisdictions. The ship is heading in the direction of the southeast Alaska town of Sitka 273 kilometres to the north, travelling at about less than a kilometres per hour, Coast Guard spokesman David Mosley said.

There are no immediate concerns regarding the community of about 9,000, however. Mosley said the town is just a reference point at this time and that currents could always change.

“Our main concern is maritime traffic,” he said. “We’re trying to minimize any safety concerns, alerting vessels. We don’t want any vessels to run into it.”

A Coast Guard C-130 was heading to the ship to pinpoint the exact location and check if a data buoy was successfully dropped on it Saturday.

The vessel has been adrift since it was launched by the tsunami caused by the magnitude-9.0 earthquake that struck Japan last year. About 5 million tonnes of debris were swept into the ocean by the tsunami.

The ship has been identified as coming from Hokkaido, Japan.

Beside boat traffic, another concern is the ship’s impact on the maritime environment after floating at sea more than a year. What’s on board is unknown. Also unknown is whether the ship is carrying fuel.

The vessel, named Ryou-Un Maru, is believed to be 46 to 61 metres long, according to Mosley.

Officials are studying various options on how to deal with the ship, including scuttling it at sea or towing it to land.

The Japan earthquake triggered the world’s worst nuclear crisis since the Chernobyl accident in 1986, but Alaska state health and environmental officials have said there’s little need to be worried that debris landing on Alaska shores will be contaminated by radiation. They have been working with federal counterparts to gauge the danger of debris including material affected by a damaged nuclear power plant, to see if Alaska residents, seafood or wild game could be affected.

In January, a half dozen large buoys suspected to be from Japanese oyster farms appeared at the top of Alaska’s panhandle and may be among the first debris from the tsunami.

The United States needs to hurry up and prepare for debris from the tsunami, US Senators Mark Begich of Alaska and Maria Cantwell of Washington state said last week in Seattle, before the ship crossed into US waters from the coast of Canada. The Democratic senators said they’re seeking three things from the federal government, including emergency research money to better understand where the debris is going and how much can be expected on US shores.

2012, APN Holdings NZ Limited