The “top freshwater fish killer” that has existed for 100 million years has recently made waves in China

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Recently, the incident of rounding up and catching “strange fish” in yunchan lake, Central Park of Ruzhou City, Pingdingshan, Henan Province, has attracted much attention. A live video shows that online onlookers once exceeded 30 million.

After nearly a month of pumping, 300000 cubic meters of lake water was basically drained. At about 00:00 on August 27, the truth finally surfaced: the identity of two “strange fish”, one large and one small, was confirmed. They were alligator finches that had existed on the earth for more than 100 million years.

Captured alligator finches. Source: Central Park of Ruzhou City

How powerful is the alligator eel, known as the “top freshwater fish killer”?

As a unique species in North America, how did it come to China? What impact has it brought to us?

Wen | Xie Fang, observer of lookout think tank

This article is compiled by outlook think tank.


Two aggressive fishing operations

After the “strange fish” appeared, the management of the Central Park of Ruzhou City initially tried to catch it with large-scale throwing nets, and later hired a professional fishing team to find the “strange fish” using sonar positioning. However, alligators and finches may lurk because they are disturbed. Subsequently, the park purchased a large purse seine and baited it, but nothing was found.

The surface of yunchan lake is very wide and the water depth is different. The deepest point is seven or eight meters. There is a U-shaped pipe in the middle. It is speculated that the alligator finches hid here after being frightened. The light in the U-shaped pipe is poor, the oxygen is insufficient, and there are silt, aquatic plants, etc., which makes it difficult to catch.

Finally, the park decided to drain the lake.

Source: News 1 + 1

In the early stage, the water body salvage and drainage work is mainly carried out by the park staff, and the cost is not very high. After the water is drained, it is difficult to catch alligator and finch eels in the U-shaped pipe only by the original team. Therefore, a volunteer rescue team of nearly 20 people joined in.

At about 0:00 on August 27, two alligator finches, one large and one small, were captured. The large one was about 90 cm long and weighed about 25 Jin, and the small one was about 70 cm long and weighed more than 10 jin. The arresting team member said, “when we pumped the water almost, we entered the pipeline more than 100 meters deep and captured it. At that time, the water level was less than one meter.”

At present, the management of Ruzhou city park has carried out harmless treatment and arranged personnel to carry out professional disinfection of the lake area.

Not only in Ruzhou Central Park, but also in Guangzhou Baiyun Lake Park during the Spring Festival of 2019.

On February 9 of that year, the staff of Baiyun Lake Park found a “strange fish” when patrolling. It was huge and occasionally floated up, exposing a small part of its body to the water. It was confirmed by experts as an alligator finch eel.

On the 13th, the fishing operation entered the implementation stage. The scheme of “purse seine method + trawl method” and “throwing net method” was adopted. The lake area was divided into three sections and trawling was carried out in sections. At the same time, Baiyun Lake Management Office tries to reduce the water level in the lake by pumping and discharging the water from the pump station, so that a large area of water in the Western Lake area is exposed.

On the 15th, the fishing team completed the trawl enclosure of 300 mu of water area. The trawl was launched at 10:00 that night, and 25000 kg of fish were screened one by one overnight. At about 7:00 in the morning, an alligator eel with a length of about 90 cm and a weight of about 5 kg was caught.

However, after comparison, the fishing team found that the fish caught did not match the shape of the “strange fish” found by the staff during the inspection, so it continued to implement the purse seine, and finally successfully caught a 1.2-meter-long “bow back” alligator finch eel weighing 10 kg.

These two fish were taken back to the Pearl River Fisheries Research Institute for anatomical analysis, which became the sample data for analyzing the fish ecological population structure in Baiyun Lake.


“Strange fish” frequently appear, all of which are alligator finches

In recent months, reports about alligator finless eels have appeared in Beijing, Hunan, Guangxi, Jiangsu, Qinghai, Ningxia, Yunnan and Shandong.

At the end of July, when the residents of Baiwang jasmine garden community in Haidian District of Beijing were walking, they saw a “crocodile” more than half a meter long in the water system of the community. After that, some owners recognized it as an alligator eel. One of the old men stayed for several days and finally fished it up and handed it over to the property management.

Many owners said that they often saw people release animals in the community, usually goldfish, bullfrog, tortoise, etc., but they didn’t expect that there would be alligators and finches. Li Li, the head of a wildlife protection station in Beijing, said that the fish released most are crocodiles and finches, as well as some reptiles such as Brazilian turtles and crocodile turtles.

On August 17, an alligator finch eel in the landscape pool of a community in Jingjiang City, Jiangsu Province, bit a boy’s finger. The boy’s parents said, “the child’s wound was bleeding at that time. We cleaned it to eliminate the inflammation. There were six or seven scars on it, about 1cm.”.

On the 25th, two alligator finches (each about 1m long and weighing about 7.5kg) were successfully captured in the lotus pond of Xishan Scenic Area in Guiping City, Guangxi.


On the same day, a “strange fish” appeared in the landscape pool of a community in Kunming, Yunnan. The property management drained 400 cubic meters of water in the pool in three hours and caught an alligator finch eel with a length of about 60 cm and a weight of about 3 kg.

The next day, several “strange fish” appeared in an artificial lake in a community in the West Coast new area of Qingdao City, Shandong Province. They were more than one meter long and had long beaks and fangs. They were feeding on other fish in the lake, and were suspected to be an alien species, alligator finch eel. After the local government learned the news, it quickly organized the community property to carry out pumping fishing. At present, two alligator finches have been caught ashore, but there are still fish in the lake that have escaped the net, and the fishing is still in progress.

In addition, students from Sun Yat sen University have also photographed alligator finches in the lake on the campus.

The question is, how did they enter China?


“Top freshwater fish killer”

There are no alligators or finches in China.

At present, there are two main ways to introduce foreign fish into China – aquaculture and ornamental fishery. Gu dangen, a scientist at the post of alien species invasion prevention and control of the national bulk freshwater fish industry technology system, introduced that most of the alligator finches in China in the early period came through illegal smuggling channels. At the beginning of this century, they were introduced as ornamental fish and began artificial breeding.

There are two reasons why they become ornamental fish: first, the meat is rough and not delicious; second, the shape and personality are unique.

The alligator finch is a unique species in North America, also known as the lucky alligator. It belongs to the order of finch eels, the family of finch eels, and the genus of great finch eels. It is mainly distributed in the coastal rivers and estuary waters of the Gulf of Mexico from Mexico to Florida, the lower reaches of the Missouri River and the Ohio River. It is one of the world’s top ten ferocious freshwater fish,.

They have existed on the earth for more than 100 million years. During the long process of evolution, their scales have become as thick as a coin, and they are also attached with enamel materials similar to the surface of human teeth, which can help them resist more than 90% of the damage when encountering natural enemies. At the same time, their mouths are as sharp as crocodiles, and their protruding upper and lower jaws are full of two rows of sharp teeth, which can cause fatal damage to their prey.

With thick scales and sharp teeth, alligator finches are always at the top of the food chain in the Great Lakes basin of the United States, hence the name “top freshwater fish killer”. Their prey includes a variety of fish, crustaceans, amphibians, birds, small and medium-sized mammals, and they are hardly picky.

In order to adapt to the environment, the swim bladder of the alligator eel has also evolved a function similar to that of an air bag. In the absence of oxygen in the water, they can directly breathe the oxygen in the air, and can also float to the surface by filling the swim bladder with air. Therefore, they can survive on the land for a short time.

The body length of adult alligator finches is generally 1.2 to 1.8 meters, and the longest can be up to 3 meters. They are huge and lack natural enemies, and are extremely harmful. In addition, the breeding ability of the alligator eel is also very strong. It can produce tens of thousands of fish eggs every year, which are green and toxic.

The unique and fierce alligator finches have naturally aroused consumers’ desire to buy ornamental fish. It is understood that at present, the breeding of alligator finches is mainly concentrated in Guangdong. Because of the large breeding capacity, alligator finches are easy to buy online and offline, and the price is relatively low. Generally, you can buy a young fish for more than ten yuan, and the price is about several hundred yuan.

Alligator finch eel as an ornamental fish. Figure | figure worm creativity

However, alligator finches eat a lot and grow fast. They can grow to more than 1 meter in a short time. Some owners choose to abandon them; In addition, some people specially bought alligators and finches to release them.

Gu dangen said, “most of the spread of alligator finches is human spread. The ‘strange fish’ found in Ruzhou may be released into the lake after being purchased for breeding.”

The management of Ruzhou Central Park also said that it was suspected by relevant experts that it was “artificially released”.

The alligator eel lacks natural enemies in China. Once it enters the natural waters, it will bring disaster to the local fish community and seriously endanger the aquatic biodiversity and the ecological security of the waters.

For example, after the fish in a certain water area are preyed on by alligator eels and greatly reduced, the algae used as food by fish will flood in a large area, forming a single species advantage in the water area, which may lead to hypoxia in the water body and trigger ecological disasters in a certain range. Another example is that when food is in short supply, alligator finches may even attack humans.

Mr. Kong, a staff member of Henan water conservancy investment group who participated in the fishing operation in the Central Park of Ruzhou, said that during the search, they found that the fish in the lake had been almost eaten. If left unchecked, the alligator finches might attack the people near the water area.


Stick to the “biosafety defense line”

The behavior of abandoning and releasing alien species at will is seriously threatening the national “biosafety defense line”.

In recent years, the number of invasive alien species in China has been on the rise, and China has become one of the countries that suffer the most serious damage in the world.

According to China’s ecological environment situation bulletin 2020, more than 660 alien invasive species have been found in China. Among them, 71 species have caused or have potential threats to the natural ecosystem, and have been included in the list of alien invasive species in China. 219 species have invaded national nature reserves.

The water hyacinth originated in South America propagates rapidly and covers the water surface, causing a large number of aquatic organisms to die due to lack of oxygen and sunlight; Pine wood nematode originated in North America infects pine wood nematode disease (known as “AIDS” of pine trees), and pine trees die after 40 days of infection; It is a mosquito eating fish native to central and North America and introduced to control mosquito breeding and malaria transmission. At the place of invasion, medaka and spike fish are endangered; In 2019, the meadow Spodoptera invaded China, seriously harming the growth of corn and other crops; wait.

With regard to the previously introduced alligator finches, Gu dangen said, “when the list of foreign species under national key management (the first batch) was released and implemented in 2012, there was no evidence that alligator finches could breed in the wild, and the number was relatively small at that time. However, the current data have proved that alligator finches can breed in the wild. Customs and agriculture

Ministry of industry and Rural Affairs

The gate has already started to take action to stop the introduction of these species. “

On April 15, 2021, China formally implemented the biosafety law of the people’s Republic of China (hereinafter referred to as the biosafety law), which stipulates the contents of preventing the invasion of alien species and protecting biodiversity, and requires the formulation of a list of alien invasive species and management measures. To this end, this year, the Ministry of agriculture and rural affairs and other relevant departments formulated the notice on printing and distributing the general plan for the census of alien invasive species, and conducted a nationwide census of 10 major alien aquatic organisms, including the alligator finch eel.

Ren Dapeng, Professor of China Agricultural University, introduced that “alien invasive species” and “alien species” are two different concepts. Alien species are not all invasive species. Whether they belong to invasive species requires long-term scientific assessment. However, as long as it is an alien species, whether it is listed or not, there are strict management regulations. For example, paragraph 3 of Article 60 of the biosafety law stipulates that no unit or individual may introduce, release or discard alien species without approval.

From August 1, 2022, the measures for the management of alien invasive species jointly issued by the Ministry of agriculture and rural affairs, the Ministry of natural resources, the Ministry of ecological environment and the General Administration of Customs will be formally implemented. This is the first management method for the prevention and control of alien species in China.

The Measures specify that the management of alien invasive species is an important measure to maintain national biological safety, and the principles of risk prevention, source control, comprehensive treatment, coordination and public participation should be adhered to. No unit or individual may introduce, release or discard alien species without approval. Those who introduce, release or discard alien species without approval will be punished in accordance with Article 81 of the biosafety law.

Article 81 of the biosafety law stipulates that if an alien species is released or discarded without approval, the relevant department of the people’s government at or above the county level shall, according to the division of responsibilities, order the release or disposal of the alien species within a time limit and impose a fine of not less than 10000 yuan but not more than 50000 yuan.

reference material:

1. Many places report finding “strange fish” | Jiang Ziwen, surging news, August 28, 2022

2. “Strange fish” caught, two | Tian Meng, CCTV news, August 27, 2022

3. What is the origin of this “strange fish”? Expert interpretation | CCTV news, 2022-08-26

4. Are there “strange fish” in the ditch of the community? It was originally an alligator eel! It is illegal to bring in and release alien species at will | Huang pinchao, Beijing Evening News, 2022-08-01

5. The fish and shrimp in the pool were “destroyed”! Kunming: an expert group has been established to investigate | Chuncheng evening news, August 28, 2022

6. Alligator finches, how hard is it to catch this “strange fish”? Aquatic experts share their arrest experience in Guangzhou | Chen Liang, Yangcheng Evening News, 2022-08-28

7. Treatment case of alien invasive aquatic organisms | Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, ocean and fishery, issue 10, 2020

8. Introduction to common alien aquatic organisms in Guangdong waters | Gu dangen, Hu Yinchang, ocean and fishery, issue 10, 2020

9. Alligator eel: the overlord in North American rivers | Cheng Zui, children’s science and technology, issue 11, 2013

10. Recently, “strange fish” alligators and finches have been found in many places! What exactly did it come from| Han Xueying, Zheng Shu, voice of China, Central Radio and television station, 2022-08-29

11. Biosafety law of the people’s Republic of China | Chinese government website

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