Pumice stones that are drifting ashore Japan's southwestern islands are affecting local fisheries and operations of passenger ships.
The massive numbers of stones come from an undersea volcano that erupted in August along the Ogasawara island chain in the Pacific Ocean.
Aquaculture producers of mozuku, a type of seaweed, in Okinawa Prefecture, usually seed the seaweed in a tank and transplant it in the sea at around this time of the year.
But the arrival of the pumice has been keeping them from doing so since mid-October.
The farmers say the harvest of mozuku will be affected as the seaweed cannot grow enough in tanks.
One farmer in his 40s said that local seaweed farmers were hit by the coronavirus crisis, then by the pumice. The man said he feels insecure about his livelihood.
About 500 fish raised in a net farm at a port in Uruma City have been found dead after pumice stones arrived there. The fish are believed to have died due to lack of oxygen in seawater contaminated by the pumice, or after their gills were clogged by the stones.
The amount of damage is estimated to be about 3 million yen, or about 26,400 dollars.
Drifting pumice stones are also disrupting operations of passenger ships between the main island of Okinawa and smaller islands around it.
The operator of ferry and high-speed boats between Nanjo City on the main island and nearby Kudaka Island suspended its services on Thursday afternoon.
The operator says the engines of the craft could break down due to the stones.
The crew of a ferry that arrived at a port in Nanjo City on Thursday afternoon have found many pumice stones on the filter of a device that takes in seawater to cool the engine.
Chief engineer Nishime Takeo said that if pumice stones continue to drift ashore, vessels cannot sail for a couple of days.
He said that sea transportation is indispensable for islanders as they use it to go to hospital on the main island. He said that he wants the central and local governments to remove the stones by all means.