Four sperm whales that got stranded ashore died on Saturday in the coastal city of Yancheng, in East China's Jiangsu province, more than 24 hours after rescue attempts began.

The dead whales were lying ashore with most of their bodies out of water. Pieces of flesh had been cut from at least one of the whales' bodies for food, according to a report by China Radio International on Sunday.

The whales, which were up to 18 meters long and weighed from 22 to 44 tons, were found alive by residents on Friday morning.

The whales, including a female, were still struggling when they were spotted, residents said.

"Two of the whales struggled violently on Friday, pushing continuously against the water with their tails," said Fang Wei, who lives nearby and joined the rescue work.

People from the city's fishery department and the border detachment also rushed to the beach when they heard the news.

Five rescue plans were put forward, including using helicopters and large vessels to pull the whales back out to sea, digging water channels to refloat them and waiting for a huge rising tide.

"But because of the size and physical condition of the whales, all plans failed," said Xu Xinrong, an animal researcher from Nanjing Normal University who specializes in cetacean mammals.

"Small-sized whales sometimes can be rescued when they are stranded on the beach, but the mass stranding of big whales is fatal," Xu said.

It was China's first mass beaching of whales since 1985, when six whales died in the Fujian province.

Hundreds of people gathered on the beach to witness the spectacle and take pictures.

"It's sad to see such enormous creatures lie still on the beach, but not everyone has the chance in a lifetime to witness such a rare thing," Fang said.

Sperm whales, though distributed in nearly all of the earth's oceans, prefer deep waters and can dive to a depth of 2,200 meters, said Xu. Local authorities said that disposing of the whale carcasses was now a problem.

"Generally there are three ways to dispose of a whale carcass: make a specimen of it, bury it on the beach or let the tides take it back into the ocean," Xu said.

Because whales are listed as a national grade II animal for key protection in China, local authorities were waiting for instructions from the Ministry of Agriculture's fishery command center.