State aquatic officials are investigating whether a 24-foot boat that washed ashore on Windward Oahu is tsunami debris from Japan.

The boat was found Sunday by a family in Puna­luu.

Officials said registration numbers are clearly visible and that the state will work with federal marine officials and the Japan Consulate General to determine the boat’s origin.

State aquatic officials Monday said the boat has green mussels on it that are native to Japan.

Officials plan to examine and clean the boat at their Halawa base yard Wednesday. Officials also are expected to search the area where the boat ran aground to see whether any green mussels, considered an invasive species, were dislodged.

If confirmed, the boat would be the fourth vessel and fifth piece of tsunami debris found in Hawaii waters. An estimated 5 million tons of flotsam went into the sea from the tsunami that followed a 9.0-magnitude quake in March 2011.

Four of those confirmed items have arrived in Hawaii since Sept. 18: a large blue plastic bin, a fishing boat recovered 700 miles north of Maui by a Hawaii longline fisherman, a skiff found at Midway Atoll and a skiff in pieces found at Kahana Bay on Oahu.

Officials said 17 items gathered in the U.S., Canada and Mexico so far have been confirmed as lost during the Japanese tsunami. As of Nov. 29 the National Oceanic and Atmospheric Administration had received about 1,400 official debris reports from the U.S., Canada and Mexico.

State and federal officials are encouraging the public to report possible tsunami debris.

Officials are worried the debris might be carrying invasive aquatic species and, if large enough, create a navigational hazard.

"While not every item may be traceable back to Japan, it is still important that the public help ensure the health and safety of our community and our coastal environment by reporting bulky, hazardous, large or unusual items in our waters or coastline," said William Aila, director of the state Department of Land and Natural Resources, in a statement. "Smaller items can be reported and disposed of safely."

To report possible debris, call the department at 587-0400 or send an email to dlnr.marine.debris@ hawaii.gov and disaster­debris@noaa.gov. For the latest information on tsunami debris, visit the NOAA Marine Debris Program website, marinedebris. noaa.gov/tsunamidebris.