NANJING - Zhu Didi and Zheng Xiaoqing caught their first glimpse of the finless porpoise, locally known as the "river pig," at the Dashengguan watercourse along the Yangtze River in east Jiangsu province. After watching a happy family of three sporting in the water, they became more determined to protect the endearing but endangered porpoise.

Zhu and Zheng are both members of the Eco-environment Protection Association of Nanjing University. In June, they learned that the World Wildlife Fund (WWF) had started a volunteer program to protect the endangered finless porpoise. Fascinated by the lovely smiles of the mammal, they quickly formed a group and embarked on their research tours.

Despite having barely known anything about the "river pig" previously, Zhu and Zheng set out to become experts.

"The finless porpoise is in a very critical stage now. Its population is even lower than that of the giant panda. But people seldom pay any attention to them," Zhu said, adding that maybe the lack of attention was caused by its nickname "river pig," which doesn't sound so cute or cuddly.

Living exclusively in the Yangtze River and its connecting Poyang and Dongting Lakes, the Yangtze finless porpoise was listed as a second-class state-protected animal, but despite that classification, its number has continued to drop over the past years.

In August, Zhu's group, together with some experts and interested citizens, went to Nanjing, Zhenjiang, Poyang Lake and several other places to track down the porpoise, but only a few could be found. When they arrived at Poyang lake, all they could see was a large swath of grassland left by the drought.

"The fishermen told us that fifty years ago there were so many finless porpoises in the river that they found it hard to row the boat, but now we can hardly spot any,"  Zhu said.

According to surveys from the Hydrobiology Institute of the Chinese Academy of Sciences, the population of the finless porpoise stayed at around 2,700 in 1991. By 2006, the number had dropped to 1,200-1,800, less than the total number of wild giant pandas. At present, the number of Yangtze finless porpoises is around 1,000.

The decline is mainly caused by human activities such as waste-water discharge, over-fishing, and channel construction, according to Zhu.

"If nothing is done, the finless porpoise might face the same fate as the Baiji dolphin. Experts told us it could become extinct within 15 years," Zhu said.

After finishing initial research, Zhu and her group went to local communities to bring attention to the porpoise's plight. It seemed children and the elderly were among the most interested in their presentation.

Zhu said most people interviewed knew little about the finless porpoise, some even could not tell them apart from the Baiji dolphin. Worse still, the fishermen living along the Yangtze River were unaware of the implications of the dwindling number.

"What we are doing now is to do what we can to make people more aware of the significance of the matter, so we are planning events such as salons and flash mobs to attract more attention," Zhu said.