JOURNALIST Xu Yaping's new mission in life is to save the roly-poly "river pig," the finless river porpoise that is nearing extinction in the Yangtze River and nearby lakes.

The small, stout gray porpoise without a dorsal fin is famous for what appears to be a cute smile.

But there's nothing to smile about these days.

"If the river porpoise becomes extinct, I swear I will drown myself in the Yangtze River," the 47-year-old conservationist from Xiangyin County, Hunan Province, told Shanghai Daily in a recent interview.

In 2001, scientists announced the functional extinction of white-flag dolphins or baiqitun, leaving the river porpoise (jiangtun) as the only fresh-water cetacean in the Yangtze River and its environment, notably Dongting Lake in Hunan Province and Boyang Lake in Jiangxi Province.

This subspecies only exists in China.

According to the World Wildlife Fund, there are only around 1,000 river porpoises in the Yangtze River's main stream and in lakes.

Their number is decreasing every year because of environmental degradation and pollution, lack of fish for food, and illegal fishing, often with electric current and explosives, that kill porpoises as well as fish. Boat propellers too kill porpoises.

The population is decreasing by 10 percent every year and their physical condition is deteriorating. A pod died last year of unknown causes.

River porpoises have lived on earth for more than 25 million years. Scientists believe that without proper protection, they will become extinct in 15 to 20 years and may become functionally extinct before then.

Porpoises are much smaller than dolphins, with small, rounded heads and no beaks. They are much shyer than dolphins. These river porpoises are especially small and often underfed, measuring only 1.2 meters to 1.9 meters in length. Their healthy brethren are quite a bit bigger.

"River porpoises are on the top of the food chain in the Yangtze River," said Xu who began conservation work in 2011 when the World Wildlife Fund appealed to him because of his known concern for the environment.

"If they become extinct, it means that the ecological environment has been severely damaged. Ultimately, there will be retribution against us and our descendants for what we have done. The condition of these mammals as well as the environment is a source of agony."

River porpoises are a "second-class" protected animal in China, meaning permission from provincial or municipal authorities is needed to hunt, catch and trade them. Many fishermen and hunters don't bother with permission.

Last year more than 30 river porpoises lost their lives, including a pod of 12 in Dongting Lake last spring. Some were killed by ships' propellers, some died of disease, and other causes were not identified. Some appeared to be malnourished.

Most of the dead porpoises were four to six years old, prime reproductive age and the deaths clearly lowered reproductive capacity.

Xu saw the dead porpoises in Dongting Lake and transported several bodies to a laboratory for an autopsy. The advanced state of decomposition made it impossible to determine the cause of death.

"It remains a mystery," said Xu, adding that the main danger factors are polluted water, illegal fishing, reckless dredging of rivers and lakes and removal of sand.

Since the 1980s, the rapid industrial and other development along the Yangtze River and in its basin have severely damaged and disrupted the fresh-water habitat for many species.

"The water level of Dongting Lake and the Yangtze River has dropped in recent years, reducing the habitat area for porpoises and the pollution makes it worse," Xu said.

Excavating for sand has destroyed the spawning ground of fish, which are eaten by porpoises in a disrupted food chain.

"The crisis of the river porpoises is actually the crisis of the whole Yangtze River ecological environment," said Xu. "The damage of the environment will cause more problems than the extinction of river porpoises."

Humans suffer as well as porpoises and other freshwater creatures. A Lack of clean water and shrinking fish resources have also caused economic problems for fishermen living around Dongting Lake.

"I have talked to many fishermen, and they all complained of low incomes," said Xu.

A fisherman named Duan Fukuan told Xu that his family of five struggles to get by on an annual income of only 10,000 yuan (US$1,624). Since they don't have much education, fishing is their only means of livelihood.

Xu has been an animal lover since his childhood. In the late 1980s, he worked at a hotel in Yueyang, a city near Dongting Lake. Every day he saw pods of river porpoises frolicking in the lake.

"Back then I was really fond of the porpoises," he said. "Every time I bought fish for the hotel from fishermen, I told them not to hurt the porpoises. I regard the animals as my family."

He didn't feel the urge to do something until 2011, when he was director of the Yueyang office of the Hunan Daily. A caller from the World Wildlife Fund told him that only around 100 porpoises were surviving in Dongting Lake. The organization appealed to him to help the porpoises. "And I believe that's what my lofty cause is," he said.

Late that year, Xu and other volunteers founded the Yueyang River Porpoises Protection Association. Its aim is to convince the government to give porpoises more protection as a "class-one" (hunting or trading needs permission from the State Council) endangered species, to establish a porpoise reserve on Dongting Lake, and to study the possibility of off-site conservation for porpoises in a safe setting.

The group established a patrol team to track down and report illegal fishing, including use of explosives and electric current in the lake. They patrol night and day, on water and on land.

"We have 14 members and we promised each other that if anyone loses their life during work, the others will take care of their family," Xu said.

The dangers of the patrol are not exaggerated. Volunteers have been beaten up on night patrols and have received threatening calls and been subjected to other menace.

Early this year, Xu almost lost his life. It was February 10 and Xu and several other volunteers visited fishermen on Dongting Lake since it was Spring Festival and they wanted to pass on good wishes. On the way he noticed electric-current fishing. He immediately called the fisheries administration and tried to collect evidence on his own. He slipped on the deck, however, lost consciousness and also bumped into something that caused his small intestine to rupture.

During their patrols, the team has rescued other animals from illegal fishing and hunting, including a moose, sturgeon, swans and other protected birds.

An aid center helps injured or ailing river porpoises.

The association also carries out education on porpoise and river conservation, giving lectures, publishing advertisements and sending pamphlets to government officials, students and professionals. Xu himself has written 31 articles on river porpoises in the Hunan Daily.

The association now has more than 10,000 volunteers, according to Xu, but he says debts are mounting despite his own investment of 1.3 million yuan.

Asked about the government's attitude toward protecting the porpoises, Xu said only, "It's really hard to say."

"I once hesitated for four months, thinking whether I wanted to do this because it's dangerous, hard, heavy and urgent work. But now the happiness of seeing a healthy, living river porpoise is beyond believing."

Xu's family supports him. His wife sometimes joins him on patrols and his son helps publicize the need to save the river porpoise.

"Everyone in my family is animal-friendly," Xu said. "Even my father, who is over 80, still chases people illegally hunting birds."

Protecting the porpoise is a task for the government as well as society as a whole and it's impossible for volunteers to do it all.

"But I will do everything I can because it's worth the sacrifice," he said.

"For the next 10 years, we need to grasp every second to race the clock to extinction," he said.