After surviving 200m years, fish faces peril
THE Chinese sturgeon is often addressed as the “panda in water,” because it is a rare species that lives only in China.
With a history of over 200 million years, the living fossil that has survived huge changes in nature is now facing extinction due to overwhelming water-use projects, pollution, overfishing and other human activities.
The Chinese sturgeon is a typical anadromous that migrates between ocean and fresh water in different phases of its life. It has the longest migration of any sturgeon in the world — more than 3,200 kilometers each time.
Chinese sturgeons spawn in the upper reaches of Yangtze River in November. The juvenile fish travel all the way to the estuary from May to October before heading to the ocean. They dwell along the coast of China’s eastern areas and get back to the estuary again when reaching sexual maturity (9 years old for males and 14 years old for females). Here, they get themselves prepared for the long journey and breeding by eating sufficient foods.
An adult measures up to 4 meters long, and weighs over 450kg, ranking among the largest sturgeons in the world.
In the 1970s, there were an estimated 2,000 spawning Chinese sturgeons in the Yangtze River but the number has dwindled to several hundred due to habitat destruction. The channel for adult fish migrating to spawning sites such as the Jinsha River was blocked after the construction of the Gezhou Dam, a hydroelectric project, in the early 1980s.
“The general number of Chinese sturgeons that we detect each year at the estuary of the Yangtze River is decreasing, regardless of all the saving, artificial breeding and releasing,” says Chen Jinhui, deputy director of the Department of Shanghai Yangtze Estuarine Nature Reserve for Chinese Sturgeon.
About 5 million Chinese sturgeons were released in the middle Yangtze River over the past 30 years, and over 10,000 were released in Shanghai in the last 10 years. But only about 100 Chinese sturgeons were detected by scientists at the estuary last year. The number is expected to decrease again, since no natural breeding of Chinese sturgeons was detected last November in the upper reach.
With a history of over 200 million years, the living fossil that has survived huge changes in nature is now facing extinction due to overwhelming water-use projects, pollution, overfishing and other human activities.
The Chinese sturgeon is a typical anadromous that migrates between ocean and fresh water in different phases of its life. It has the longest migration of any sturgeon in the world — more than 3,200 kilometers each time.
Chinese sturgeons spawn in the upper reaches of Yangtze River in November. The juvenile fish travel all the way to the estuary from May to October before heading to the ocean. They dwell along the coast of China’s eastern areas and get back to the estuary again when reaching sexual maturity (9 years old for males and 14 years old for females). Here, they get themselves prepared for the long journey and breeding by eating sufficient foods.
An adult measures up to 4 meters long, and weighs over 450kg, ranking among the largest sturgeons in the world.
In the 1970s, there were an estimated 2,000 spawning Chinese sturgeons in the Yangtze River but the number has dwindled to several hundred due to habitat destruction. The channel for adult fish migrating to spawning sites such as the Jinsha River was blocked after the construction of the Gezhou Dam, a hydroelectric project, in the early 1980s.
“The general number of Chinese sturgeons that we detect each year at the estuary of the Yangtze River is decreasing, regardless of all the saving, artificial breeding and releasing,” says Chen Jinhui, deputy director of the Department of Shanghai Yangtze Estuarine Nature Reserve for Chinese Sturgeon.
About 5 million Chinese sturgeons were released in the middle Yangtze River over the past 30 years, and over 10,000 were released in Shanghai in the last 10 years. But only about 100 Chinese sturgeons were detected by scientists at the estuary last year. The number is expected to decrease again, since no natural breeding of Chinese sturgeons was detected last November in the upper reach.
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