The critically endangered Chinese sturgeon (Gray), a large anadromous fish, is strictly protected in Chinese waters, where it is deemed to be a national treasure. Mature individuals enter the Yangtze River estuary from July to August, before entering their spawning ground the following year from October to November. Historically, sturgeon spawned in the upper reaches of the Yangtze and lower reaches of the Jinsha Rivers, but construction of Gezhouba Dam (the first dam in the Yangtze mainstream) blocked this migratory route. A relatively stable spawning ground has since developed below this dam. From 1982, the Yangtze River Fisheries Research Institute has conducted annual monitoring of natural breeding of sturgeon within the newly formed spawning ground. Between 1982 and 2013, sturgeon spawned annually, though both fecundity and frequency of reproduction declined. Whereas the number of mature fish arriving at the spawning ground annually exceeded 2 000 individuals in the early 1980 s (near the closure of Gezhouba Dam), it also dropped to fewer than 100 individuals in recent years. Prior to impoundment of the Three Gorges Reservoir (1984-2003), sturgeon spawned on average 1.8 times per year, though this decreased to 1.1 times during impoundment (2004-2012). Although controlled propagation and augmentation of sturgeon stocks has been performed from as early as 1983, both mark-recapture and molecular genetic identification reveal more than 90% of juvenile within the Yangtze estuary originated from natural reproduction. Thus, it is critical that natural reproduction of the fish may be maintained in the only knowing spawning ground.Though there was an apparent interruption in sturgeon spawning between 2013 and 2015 at this only known spawning ground, we report a resumption of spawning in 2016, during which time 67 egg (or egg membrane) and 22 larval sturgeon were collected by bottom draft-net, and 454 eggs were found in the stomachs of 10 egg-preying fishes. Underwater camera observations also revealed five sites with fertilized sturgeon eggs adhering to the substratum. The spawning ground was 300 m downstream of the Dajiang power plant (Gezhouba Dam). Spawning likely occurred during the early morning of November 24; estimated fecundity was less than two million; water temperature at the time of spawning was 19.7℃; and the flow and water level were 6610 m³/s and 39.7 m, respectively.Recent monitoring indicates the Chinese sturgeon has changed from being a "continuous" to an "accidental" spawner, and that this is likely to continue. Increased water temperature was probably the main reason for the failed spawning between 2013 and 2015, as the Three Gorges Reservoir significantly altered water temperature within the middle reach of the Yangtze River, but other factors, such as navigation, waterway regulation, overfishing and environmental pollution, have also reduced environmental quality at the spawning ground and may have contributed to spawning failures. Without effective environmental management, the natural population of Chinese sturgeon is at high risk of extinction.In 2015 the Ministry of Agriculture issued the "Chinese Sturgeon Rescue Action Plan" to protect Chinese sturgeon, which introduced several conservation programs, such as artificial restocking, habitat management and restoration, and the prohibition of fishing. Artificial restocking of Chinese sturgeon would also be improved by increasing the number and size of released individuals, thereby increasing their survival. In the middle and lower reaches of the Yangtze River, port, waterway, shipping and other construction projects should be managed to avoid any negative impact on the habitat and migration of Chinese sturgeon. In particular, environmental protection of Hubei Yichang Chinese Sturgeon Natural Reserve needs strengthening to maintain the hydrological conditions of spawning grounds. Additionally, improvement and rebuilding of Chinese sturgeon spawning grounds would facilitate -protection of Chinese sturgeon.