Expedition ship sturgeon spawning near the gezhouba dam enter. This picture came from Chen Xingwang
Sturgeon for two consecutive years after the cessation of natural reproduction, Shanghai Yangtze estuary in spring and summer this year a large number of Chinese sturgeon larvae, number times the number as in previous years, more than 10 years. Experts speculate that the Chinese sturgeon may have found new spawning grounds.
To this end, the Department of agriculture started again after a lapse of 30 years the Chinese sturgeon research survey, from September 30 this year to March next year, nearly 200 research team gathered in gezhouba downstream of the Yangtze River in Anqing, Anhui Province more than 1000 km section, look for sturgeon spawning and for environmental remediation and improvement, explore new protection mode.
November is sturgeon's breeding season, CAFS, the Yangtze River Fisheries Research Institute of China, Chinese Academy of Sciences, Institute of Hydrobiology, the China three gorges Corporation Chinese sturgeon Research Institute scientists in Institute of Chinese Academy of Sciences, Ministry of water resources project, jointly organized a large expedition against the sturgeon spawning.
As the expedition activities technical team leader of the Chinese Academy of fishery Sciences surging Yangtze River Fisheries Research Institute researcher Wei Wei told the news (www.thepaper.CN), although there is strong evidence, 2014 spawning Chinese sturgeons in the Yangtze River have been natural breeding, but spawning grounds have been migrated, we can find is still unknown.
Sturgeon originates from the Cretaceous period 140 million years ago, dinosaurs in the same period, from the East along the Yangtze River upstream migration of spawning each year gave birth to offspring, but the migratory spawning wild Yangtze River sturgeon population is now no more than hundred.
Stop breeding for two years, one of the last spawning disappear
Scientific research ships and not far from the gezhouba dam, here is one of the remaining sturgeon spawning.
The morning of November 19, Rouge section between dam and gezhouba dam the Yangtze River in Yichang city in Hubei Province, from private rental expedition ship again sailed out of the port, near the gezhouba dam to the possible existence of Chinese sturgeon spawning into. Difficulty catching the end of scientific personnel from the egg NET, small fish shrimp, waste of network and found no traces of juvenile sturgeon eggs.
This body of water, is the only spawning sturgeon after the damming of gezhouba project is located.
Sturgeon are known as the "Panda in water" has evolved on the Earth 140 million years, ancient rare fish is native to China, is one of the most primitive extant fish species. 1989 Chinese sturgeon is listed as national key protected wild animals, 1997 are included in the Convention on international trade in endangered species of wild fauna and Flora (CITES) Appendix II species, in 2010 by the World Conservation Union (IUCN) level upgraded to critically endangered (CR) species.
On November 19, Wei-Wei told the Word Press, prior to the 80 's of last century, migratory over Yangtze River sturgeon is estimated to have more than 2000, 3000 km on the origin of them along the Yangtze River, jinsha River to spawn breeding juvenile sturgeon. 1981 at gezhouba closure blocked the migration routes of Chinese sturgeon, originally distributed in the Yangtze River and more than 600 km section of the upper Yangtze River spawning over 16 can no longer be used by sturgeon.
After the damming of gezhouba project, Chinese sturgeons migrate only 1800 km, about 30 km downstream of the gezhouba section 5 spawning natural reproduction. By 2012, spawning only near the gezhouba dam in one place.
2013 and 2014 for two consecutive years, researchers in the spawning activities did not monitor the natural propagation of Chinese sturgeons, which means also a spawning sturgeon finally disappeared.
At the time, Wei-Wei had predicted in an interview that "the smallest sturgeon may mean the future is born in 2012. According to the most conservative estimates, the 2012 sturgeon the largest can live up to 40 years of age, which is in more than 30 years, the species will disappear in the nature ".
2003 dam after impoundment of the three gorges of Yangtze River water temperature rise is thought to contribute to key factors of Chinese sturgeon spawning activity, interrupted. Wei Wei said Chinese sturgeon spawning activity on the water temperature is very high, at 15.3 20.3 degrees Celsius could spawn. Every year from June to July, adult Chinese sturgeons begin to migrate, fat gonadal development, in October started producing eggs. But after the temperature rise of the Yangtze River, sturgeon spawning time delayed to November.
"Winter water temperature is still too high." Scientific staff on November 19, 20th surveillance in waters near gezhouba water temperature of about 20 c, downstream at Shishou, about 19 degrees Celsius, just to achieve suitable water temperatures for spawning of Acipenser sinensis.
Wei Wei believes that because of the gezhouba dam downstream of the spawning water temperature, possible spawning of Acipenser sinensis has to move. Central America policy Dawei why top left inputs
As of November 20, the expedition team through Sonar monitoring, monitor only to about 10 from the ocean migratory Yangtze River sturgeon. "But this does not mean that all quantities, we cannot monitor the whole."
"This is not a question of protecting fish"
Salvaged egg catcher network, except for a few small shrimp and decaying organic matter, none the wiser.
Dams caused environmental change, pollution and overfishing, shipping and history, and many other factors, led to sharp decrease of Chinese sturgeon spawning ground, declining populations. Currently under the gezhouba dam in Yichang section of the propagation of the Chinese sturgeon abundance less than hundred.
Exciting is that April 2015 to August, scientists monitoring in Yangtze estuary Chinese sturgeon nature reserve to a large number of Chinese sturgeon larvae, which means Chinese sturgeon in 2013, interrupted after spawning, in 2014 and natural reproduction.
Against this background, on September 28, the Ministry of agriculture in the form of notification issued the Chinese sturgeon rescue plan (2015-2030) on September 30, and Yangtze River the Ministry of agriculture issued a circular on sturgeon spawning ground surveys, started the research activity.
"This is not a question of protecting fish", Wei-Wei thought, protection of sturgeon is in fact protecting its Habitat, that is, the ecological environment of the Yangtze River.
Find new spawning grounds of Acipenser sinensis is the focus of the scientific activities. In Yichang, Hubei Province fisheries administration Deputy Director, Yichang Deputy Director of the Chinese sturgeon nature reserve management office Luling in Chinese sturgeon protection of 30, he told press the surging, at present, primarily by sonar, underwater video monitoring, Anatomy of the Chinese sturgeon eggs, fresh eggs fish caught, looking for sturgeon spawning in the Yichang section.
Chinese sturgeon eggs with mung bean size, grey and black, the naked eye can see. It is regrettable that, more than a month, found no sturgeon spawning activity. Remove egg catcher only some garbage, dead shrimp and small fish of decaying organic matter.
Surge of juvenile Chinese sturgeon, scientists in joy and sorrow were mixed.
Wei wei, endowed of the juvenile sturgeon can be said to survive, means that the Yangtze River sturgeon population soon died out. If the Chinese paddlefish natural breeding this year, find spawning more likely. If you find new spawning grounds, the next step will establish new spawning grounds protected areas after the investigation.
Responsible for the Shishou in Hubei section of the Yangtze river expedition of CAFS, the Yangtze River Fisheries Research Institute of China Vice researcher Wang Chengyou seemed pessimistic, he felt the recurrence of natural spawning sturgeon breeding, like a "blip", just as "Baiji before extinction, is suddenly disappeared for a year, appeared the next year, then did not appear again."
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