Aging anglers find purpose protecting porpoises

Fisherman Shu Yin'an remembers coming across plenty of finless porpoises when he was young, but the animals - found only in the Yangtze River - are rarely seen these days.

The finless porpoise is the only aquatic mammal in the Yangtze. Around 1,000 are believed to still inhabit the river, as well as two lakes linked to the busy waterway.

In 1991, the population was around 2,700. But by 2006, the number had dropped to 1,800 and has since declined further. Without effective protection, the animals may become extinct within a decade.