All chapters:

Introduction

Climate

Waters and water management

Ecosystems and ecoregions

Species diversity and use of biological resources

Nature conservation: econet and protected areas

Countries & cultures

Economy

Land use

International policy

At 4,444 km, the Amur-Heilong is the longest salmon river in Asia.  Three countries – Russia, China, and Mongolia – use the salmon resources of the enormous basin.  Anadromous salmon are very abundant in the Lower Amur – autumn and summer chum (Oncorhynchus keta), pink (Oncorhynchus gorbuscha), and masu (Oncorhynchus masu).  Coho (Oncorhynchus kisutsch) frequent the Amgun River.  Anadromous chars (Salvelinus malma and Salvelinus leucomaenis) are abundant in rivers flowing to the Amur Bay, but in the Amur-Heilong do not swim more than 100 km upstream from the mouth.  Few sockeye (Oncorhynchus nerka), chinook (Oncorhynchus tschawytscha ), and steelhead (Parasalmo mykiss) occasionally visit the Amur.  Siberian taimen (Hucho taimen) and two species of lenoks (Brachymystax lenok and Brachymystax tumensis) are also quite abundant in the Lower Amur.  Other Salmoniformes species in the Amur-Heilong include graylings (3 species) and whitefish (2 species).  Resident Dolly Varden char (Salvelinus malma) occupy the Lower Amur basin up to the upper reaches of Ussury River tributaries.  All of the above species are prized in commercial, amateur, sport, or subsistence fishing.  The only anadromous salmon of the Middle (from Ussuri-Wusuli mouth to the confluence of Shilka and Argun rivers) and the Upper Amur-Heilong (Shilka and Amur basins) is fall chum, which is now scarce.  Siberian taimen, lenoks, graylings, and whitefish are common throughout the basin.  Distribution of anadromous salmon in the basin is shown in Map:Distribution of anadromous salmon species (Oncorhynchus spp.)
All salmonids spawn on pebble stream beds.  The female prepares a sort of a nest called a redd and spawns.  The male fertilizes the eggs and then the female covers the eggs with pebbles to protect against predators.  Lenoks and taimen spawn in the upper reaches of Amur-Heilong tributaries.  Masu salmon spawn from the middle parts of tributary basins to the upper reaches.  Pink salmon spawn in the middle reaches of the larger tributaries as do summer chum.  Fall chum spawn near sources of underground water.  All Pacific salmon species are monocyclic, which means they die after spawning (2-6 years).  All other salmonids are polycyclic – spawning several times in a lifetime.  Siberian taimen mature at the age of 6-7 years and live an average life span of 30 years.
From ancient times, fishing and hunting fed people along the Amur-Heilong.  The French missionary La Bruniere who visited the Amur-Heilong, Songhua, and Ussury-Wusuli in the 18th century described local populations as heavily dependent on chum.  He wrote that the country suffered great hunger in unproductive years of this fish.
Although no species of salmon is known to have become extinct in the Amur-Heilong, many populations of fall chum disappeared from the Upper and Middle Amur-Heilong, and also from the Ussury-Wusuli River.  In the 20th century, fall chum all but disappeared in China.  In the Songhua River salmon habitats were severely depleted.  In places where spawning grounds are still in good condition, chum does not spawn because those populations were exterminated by overfishing.  Some populations of brook Dolly Varden disappeared in the Ussuri-Wusuli River basin.  Many populations of Siberian taimen also disappeared.  In the 20th century all populations of salmonids declined significantly, due primarily to overfishing.  After reaching 93,500 tons in the early 1900s, the commercial catch of chum declined to 3,000 tons by the end of the 1990s, suggesting the population had collapsed.  Even if subsistence fishing by local communities reached 9000 tons, this decline still represents a major problem.