The Author Participating in Chinese Sturgeon Release and Protection Activities. [Photo by Huang Zhigang]
For years, scientific researchers and organizations have focused Chinese sturgeon's protection mostly on Yangtze River, Chinese sturgeons' breeding route. The government and organizations have held release activity annually along the Yangtze River, and promoted a great deal of campaigns and programs which are limited to river areas. However, from my point of view, since Chinese sturgeon is a typical migrating fish between river and sea, we cannot ignore the vital role that marine environment plays in a Chinese sturgeon's life cycle. Unfortunately, the marine environment is also suffering from great pollution and destruction caused by human activities and on the other hand, the public concerns on such situation is yet to be enhanced. Evidently, we need to throw more light on the importance of marine condition to Chinese sturgeon and take more actions against ecological destruction in order to preserve Chinese sturgeon's habitat.
First of all, Chinese sturgeons spend more time of their lives in the ocean than they do in the river. As we know, although Chinese sturgeon is categorized into freshwater fish, it still lives in the sea for most of its lifetime and only returns to the river when it becomes sexually mature. The most long-lived Chinese sturgeon can live up to 40 years old yet it takes a long time to reach sexual maturity, usually about 10 years and female Chinese sturgeons go back to the river to lay eggs each 2-3 years. Thus, because of comparative longer living time in the ocean, Chinese sturgeon's survival rate is also closely bonded to the marine environment.
Secondly, Chinese sturgeon migrates between the river and sea, such nature enriches its destination on the river with precious substances from ocean, and in this way, ecological diversity of the river is promoted. However, oceanic substances brought by Chinese sturgeons to the Yangtze River will no longer be beneficial if the sea itself is contaminated. Therefore, protecting the Chinese sturgeons' habitat at the estuary is, in some way, keeping the ecosystem in Yangtze River intact.
In addition, Chinese sturgeons mostly forage in the ocean and they hardly eat anything when they are swimming back to the river. Therefore, the energy and nutrients required for the long period migration mainly depend on the fat and other substances they previously stored in their bodies before the migration starts. Consequently, the quality of food resources in marine environment becomes another concern of great significance.
Moreover, there are still other factors in marine environment we need to take into account. "Water temperature is probably the main driving factor and limiting factor of Chinese sturgeon's oceanic migration and distribution; salinity and depth of water are the primal limiting factors of Chinese sturgeon's distribution along the coastline; food abundance makes an impact on Chinese sturgeon's specific migration and distribution sites."(Science China Press) Besides factors mentioned above, flow velocity, pH value, illumination intensity, transparency, and oxygen content of the water are also indispensable factors in our observation.
Unfortunately, marine pollution is widespread as other forms of pollution that we know and will greatly damage the habitat of Chinese sturgeon. "Marine pollution mostly occurs in gulfs. With the growth of population and development of industry, increasing amount of industrial wastes and sewage are poured into the sea. In China, the Bohai Sea, the Yellow Sea and the South China Sea, the very habitats of Chinese sturgeons, are all contaminated somehow."
To sum up, we can clearly see that it is so crucial to protect the marine environment as well as the Yangtze River to protect Chinese sturgeon in a more extensive way. We propose that scientists, researchers, environmentalists should work together and search for effective solutions to maintain a healthy Ocean where Chinese sturgeon live, and the media help to popularize environmental protection knowledge, to raise the public awareness of environmental protection. Most importantly, we hope that the protection of Chinese Sturgeon can provide a successful case for the protection of other species as we all share the earth together.