Oil slicks have hit the shore along a 60-mile stretch from Kyoto Prefecture to Fukui Prefecture, whose rocky coast is dotted with fish farms, fishing ports and tourist resorts, a Maritime Safety Agency (MSA) spokesman said.
"Oil has come ashore at more than seven places, from Kyogamisaki in Kyoto to Oshima lighthouse in Fukui Prefecture, where the bow of the tanker has drifted ashore," the spokesman said.
At a beach at Mikuni, about 210 miles north-west of Tokyo, villagers grimaced at the pungent odour of heavy oil as they surveyed the wreck of the ship that has caused Japan's second worst oil spill.
"This is where I swim in summer, and my mother dives for abalone," said 12-year-old Koji Ogiwara. "At this time of the year, she would normally be looking for seaweed. It's all destroyed and I don't know what we are going to do."
In Mikuni alone, a fishing town of 20,000 people, the oil spill threatened to wipe out the entire port's annual fishing income of 30m yen (pounds 260,000).
The oil slicks also threaten a stretch of rocky Sea of Japan coastline on the picturesque Noto Peninsula, east of Fukui. The popular tourist area is famous for shrimp, crabs and "Ama", women who make their livings diving for shellfish and rare seaweed without the aid of air tanks or snorkels.
Intermittent snow and cold have dogged efforts to stop the oil spill since the 13,157-tonne Russian-registered Nakhodka broke in two during storms in the Sea of Japan on Thursday.
Kenji Ondo, of the Fukui Prefectural Fisheries Organisation, said he feared long-term damage to the local industry.
"If the oil reaches rocky parts of the coast, ecosystems could be seriously damaged. If it enters the food chain via the seaweed, it could slow down the growth of organisms all the way up the chain," he said.
The MSA spokesman said that high seas had prevented an oil dispersal operation using detergent chemicals.
"We still have no idea of how much oil escaped from the vessel," he said.