A new documentary highlights the efforts made by ordinary people to protect the Yangtze, Wang Ru reports.

When Wang Ding entered the Institute of Hydrobiology affiliated to the Chinese Academy of Sciences in 1982, he began his job of looking after a Chinese river dolphin named Qiqi. He watched over the rare mammal for two decades, and witnessed its death from old age in 2002.

The Yangtze dolphins were declared "functionally extinct" in 2007.

Wang then turned his attentions to the protection of the river's finless porpoise, with the aim of preventing this mammal species from suffering a similar tragedy.

After years of hard work, the results are apparent. Eight nature protection areas have been established along the middle and lower reaches of the Yangtze River in areas inhabited by the porpoises. Wang says the success of this model was dependent on wider efforts to protect the Yangtze River overall.