 More than 160 amphibian species are known from the Yangtze basin, including the world's largest, the critically endangered Chinese giant salamander.It has declined drastically due to hunting (it is considered a delicacy), habitat loss and pollution.The polluted Dian Lake, which is part of the upper Yangtze watershed (via Pudu River), is home to several highly threatened fish, but was also home to the Yunnan lake newt.