In the past two days, Ruzhou City, Pingdingshan City, Henan Province drained the lake water to round up "strange fish in the water" and attracted attention. According to the identification of relevant departments, the so-called "strange fish" is an alligator gar , which is an invasive alien species and its origin is the Americas. Not long ago, a "strange fish" more than half a meter long was fished out of a water system in a residential area in Beijing, and was also confirmed by professionals to be an alligator gar. Why are alligator gars appearing so frequently these days? The alligator gar appears in the north where the winter is relatively cold. Can it survive the winter in the north? Beijing News reporter interviewed Gu Dangen, an expert in the prevention and control of alien species invasion in the national bulk freshwater fish industry technology system.
"Strange fish" in Ruzhou Central Park has attracted the attention of tens of millions of netizens
Recently, in Ruzhou, Henan, a citizen discovered a "strange fish" in Yunchan Lake, Ruzhou Central Park. It was large and elusive. According to local witnesses, this "strange fish" is 70 to 80 centimeters long.
Alligator gar reared in an aquarium. Photo by Yi Nian/IC photo
In the past two days, tens of millions of netizens have been paying attention to every move of the "strange fish in the lake". On August 24, a reporter from the Beijing News called the Ruzhou Municipal Government. Staff said that after identification by relevant departments, the so-called "strange fish" was initially confirmed to be an alligator gar, an invasive alien species. Fearing that the crocodile gar might injure people, relevant departments drained the lake water to arrest them.
html On the evening of August 24, on-site fishing personnel discovered a suspected fish in a 3-meter-diameter pipe. At noon on August 25, the two rescue teams and the blue sky rescue team and other personnel put on equipment and went into the water to catch fish. As of press time, the fishing was still in progress.The person in charge of the management of Ruzhou Central Park said in a live broadcast that the park is an open park, and the "big monster" in the lake is most likely a "stray pet" and is more likely to be released in the wild. Ruzhou police staff also stated in response to the media that the relevant departments are investigating the reasons for the appearance of the alligator gar. If there is any violation of law, the relevant personnel will be handed over to the public security organs for handling.
"Strange fish" appear frequently, are widely distributed and may overwinter in the north.
In fact, it is not uncommon for crocodile gar to appear in domestic waters. Not long ago, when residents of Beijing's Baiwang Jasmine Garden community were walking, they also saw a half-meter-long "crocodile" in the water system in the community. Thanks to the efforts of the community owners, the "crocodile" in the water system - the crocodile gar - was finally captured. It is reported that there are also records of the wild distribution of alligator gar in many provinces such as Guangdong, Guangxi, Fujian, Henan, Sichuan, and Jiangsu.
Gu Dangen told reporters that the crocodile gar is a giant freshwater carnivorous fish specializing in southern North America. It is a prehistoric fish and has existed on the earth for more than 100 million years. According to a previous report by the Beijing News, crocodile gar can lay more than 150,000 fish eggs at a time. After reaching temperature and humidity conditions, they will grow rapidly and eat native fish. When food is insufficient, cannibalism is harmful to them. It is said to be commonplace.
Gu Dangen said that the crocodile gar was introduced as an ornamental fish . Its body shape is quite strange and ferocious, which can satisfy people's curiosity , so many people like to raise crocodile gar. "In the early days, most of the crocodile gar were illegally smuggled. Due to the lack of supervision, it is not difficult to buy crocodile gar in the ornamental fish market."
Gu Dangen believes that crocodile gar have appeared frequently in recent years. There is both contingency and necessity. Accident is because most of the crocodile gar discovered so far were released artificially, and who released them where is very accidental; inevitability means that the harm caused by the invasion of alien species is a long process, natural reproduction and a large number of crocodile gar are artificially farmed Finally, often because the growth rate is too fast, the aquarium cannot accommodate it, or people cannot afford the cost of breeding, so they choose to artificially release or discard it. "In the past few years, crocodile gar have been discovered. It's only now that people have a deeper understanding of alien species and have begun to have a sense of protection, so they are paying so much attention."
Gu Dangen previously accepted the Beijing News When interviewed, the reporter said that if aquatic alien species cannot survive the winter and reproduce naturally after being released into natural waters, the harm will only be short-lived.He told reporters that at present, the crocodile gar has established a population mainly in the Pearl River area, and the Yangtze River basin is not yet clear.
Ruzhou, Henan is located to the north of the Yangtze River. This wild crocodile gar can grow to 70 or 80 centimeters. Does this mean that the crocodile gar can spend the winter in the north?
"The crocodile gar itself is large, and its growth rate is also different under different living environments, climate conditions and food sources. It is not impossible for it to survive and overwinter in some places in the north. This is related to the depth and temperature of the water. "The crocodile gar is not a tropical fish and its tolerance to low temperatures is not very bad." Gu Dangen said that the crocodile gar in Ruzhou may have been larger when it was released, or it may have been in the water body before. With this fish, it is difficult to judge based on the currently known information.
The method of draining the lake water is not long-lasting, but it may be the best option at present
This time, Ruzhou Central Park drained the lake water to catch alligator gar, which took several days. Some netizens questioned the necessity of this move. In fact, in addition to the dangers of alligator gar mentioned above and the concerns of government agencies to protect the personal safety of citizens, draining the lake may indeed be the best option at the moment.
Gu Dangen said: "The method of draining the lake water will definitely not last long. If there are crocodiles and gars in a large reservoir or river, we cannot do the same. But there is currently no better way, because the creatures living in the water cannot You can't see or touch it. "In addition, it's not just the alligator gar that's so difficult to catch. All invasive fish are difficult to catch. "They are too concealed."
The management problems of invasive alien fish are not unique to China. According to Gu Dangen, China's " four major fish" are herring , grass carp , silver carp and bighead carp. The fish was introduced to the United States in the 1960s, but natural populations were quickly established after the introduction, becoming the most typical invasive alien species in the United States and the most typical invasive alien species in the world. However, over the years, good governance results have not been obtained.
Gu Dangen suggested that in the future, we should strengthen the popularization of knowledge about invasive alien species such as alligator gar and eels to prevent people from breeding or releasing them at will.
's management of invasive alien species has attracted wider attention from society. Starting from August 1 this year, the " Management Measures for Invasive Alien Species " will be implemented. This is my country's first management method for the prevention and control of alien species. It has made relevant provisions from source prevention, monitoring and early warning, management and restoration, etc.
Beijing News reporter Cao Jingrui trainee reporter Ye Hongmei
editor Chen Jing proofreader Yang Xuli
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