The Wusuli River at dawn. Photos by Wang Yuanchang / For China Daily

Fishermen have been working on the Wusuli for centuries

It is dark and foggy at 4 am as Xu Chunfu sets sail on the Wusuli River, the border between China and Russia.

Also known as the Ussuri, the river is believed to be one of the least-polluted major rivers in the world.

Xu is a fisherman from Hutou town, in Jixi in Northeast China's Heilongjiang province.

The Hutou section where he fishes is the point where two other rivers that flow from the west join, and it is therefore seen as the starting point of the Wusuli River.

The 900-kilometer long Wusuli flows east into the Heilongjiang River, which further flows east into the Pacific. In this network of rivers, Wusuli has the largest amount of freshwater fish.

Fish here is so delicious that bears often come out from the forests to catch them. Due to the threat of bears, fishermen usually go into the river in groups.

Besides fish, the bears are also interested in honey. As a result, they often sneak into the homes of beekeepers to steal honey.

Beekeeping is also a major occupation in Hutou town. The honey collected from the tilia trees in the nearby forests is famous.