Text | Huang Wenrui
Recently, "strange fish" have appeared in Henan, Shandong, Yunnan, Hunan, Guangdong and other places, mainly found in the water of communities and parks, which has aroused public attention.
First, what exactly is a "strange fish"?
The "strange fish" is a crocodile eel, a species of gar, divided into the genus Large Gar and the genus Garnet. The genus is crocodile eel, Cuban gar eel, tropical gar eel, the genus is divided into spotted eel, Florida gar eel, long-snout gar, short-snout gar eel.
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The alligator eel is the most representative of the gar eel, and it is also the most common and cheapest on the market. The eel that invaded China's rivers and the large-sized gar in the documentary are basically it, this gar grows extremely fast and is more aggressive in the gar.
Crocodile eel is a genus of finches, finches, and large finches, scientific name Atractosteus spatula, also known as "ghost rocket", "foy crocodile" and "big finches", is a fierce carnivorous fish.
The main features are:
1. The body length can reach 3 meters, the body is long barrel-shaped, the back is brown or olive, and the abdomen is light;
2. The whole body is covered with diamond-shaped scales, the most significant feature is that the upper and lower jaws are densely covered with sharp teeth and the mouth is short;
3. The swim bladder can not only provide buoyancy, but also evolve the same function as the lungs, can breathe, and can survive for two hours after leaving the water;
4. Usually lives in freshwater waters.
Second, why is the reproductive ability of the alligator eel amazing?
Crocodile eels are incredibly capable of reproduction, and may to August each year is the time to mate and lay eggs. That is, this is a species with a relatively stable estrus period.
Female and male alligator eels are not synchronized in sexual maturity, 11 and 6 years respectively, and mature females can lay 140,000-200,000 eggs per year. You read that right, the number of eggs it lays is in tens of thousands, and the eggs it produces are pale green, sticky, and can adhere to aquatic plants and stones, and only take 7 days to hatch.
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In fact, the breeding of alligator eels has extremely high requirements for the external environment. When spring and summer come, the temperature gradually rises, the water temperature also rises, the crocodile eel begins to prepare to breed, and when the water temperature reaches 20 ° C - 28 ° C and the water level is high enough, the alligator eel will climb to the shallows covered with aquatic grasses and begin to breed.
In North America, because predators will eat the eggs laid on stones or aquatic weeds by predators, the egg survival rate of the alligator gar is very low, so it has not been able to flood. But in China, the lack of predators of alligator eels and the warm, humid environment will lead to a higher survival rate of eggs.
Imagine that according to the survival rate of 1/20 of the eggs, after 7 days, there will be 7,000 juvenile crocodile eels in the waters, and it is difficult to imagine how much harm to the water ecosystem will be caused by the existence of dozens or even hundreds of crocodile eels in the waters.
Why can alligator eels survive for so long?
Crocodile eels have a pair of "heavy armor" with a hardness comparable to human teeth; It is ferocious by nature, is a non-picky eater, almost all the living creatures in the water it eats, a day to eat dozens of pounds of freshwater fish, equivalent to its body weight.
The secret of the alligator eel's ability to eat is that its teeth do not have a chewing function, and they can only eat by swallowing and a special digestive system, which can be excreted and eaten at the same time.
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Fourth, why do alligator eels appear in many places on the mainland?
The natural habitat of the alligator eel was first found in North America, Europe, India and Africa, but is now mainly distributed in the east of North America, Central America and Cuba.
On the mainland, the alligator eel belongs to an exotic species. Where did it come from? First, the alligator eel was introduced as an ornamental fish and achieved reproduction; Second, the warm climate is suitable for the life of crocodile eels.
With the increase in the size of the alligator eel, the cost of feeding is also gradually increasing, some people will release or discard it, the crocodile eel has lived in the local lake for a long time, because of its lack of natural enemies, coupled with its carnivorous habits, it will be the fish in the lake to prey on the exhaustion, the algae used as food by the fish will multiply in large quantities, resulting in lack of oxygen in the water body, seriously damaging the water ecosystem. If someone finds that the local management department should be contacted in time, the local management department will report, fish, and use appropriate methods to deal with it.
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Article 344 of the Criminal Law of the People's Republic of China stipulates that whoever, in violation of State regulations, illegally introduces, releases or discards invasive alien species, if the circumstances are serious, shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and shall also be fined or fined alone. Paragraph 3 of article 60 of the Biosecurity Law of the People's Republic of China provides that no unit or individual may introduce, release or discard alien species without approval. Article 10 of the Provisions on the Administration of Proliferation and Stocking of Aquatic Organisms prohibits the use of alien species, hybrids, genetically modified species and other aquatic biological species that do not meet ecological requirements for proliferation and stocking.
If you don't want to raise it, you can hand it over to the local agricultural authorities for unified handling; If it is found that someone has released or discarded it, and is suspected of committing a crime, it will be transferred to the judicial organs in accordance with law and investigated for criminal responsibility.
5. Is it appropriate to pump water to catch alligator eels?
In Ruzhou City, Henan Province, Qingdao City, Shandong Province, and other places where crocodile eels are found, they have become new "Internet celebrities" by fishing crocodile eels by draining the lake water to earn the attention of onlookers.
Of course, this fishing method needs to drain the lake, and when facing a relatively large lake surface, there will be time-consuming and laborious, which is easy to think that it is too expensive and suspected of wasting resources.
Is there any other way to catch it? Fishing has been suggested as a less economically costly method. Similarly, in the face of the situation that the lake surface is too large, the fish body is small and the number of fish is unknown, there are drawbacks that take a long time and the removal results are unknown.
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In view of the fact that the alligator eel is a ferocious carnivorous alien species, for the sake of national biosecurity and the protection of native species diversity, the method of draining the lake and completely sanitize the execution of fish eggs is the best way to completely eliminate the invasion of the crocodile eel.
This fishing method is also a good public welfare class about biological invasion and ecological security, which is conducive to cultivating the public's awareness of biosecurity. Moreover, Article 23 of the Measures for the Administration of Invasive Alien Species, which came into effect on August 1 this year, stipulates that the management of invasive aquatic animals from aliens should take measures such as targeted fishing to prevent their further spread of harm.
6. Can alligator eels be eaten?
The answer is no.
On the one hand, although the fish meat of the crocodile eel is not poisonous, the meat is rough, very chai, far less delicious than ordinary fish meat, some people say that the crocodile eel is like a slipper wrapped in cumin, which is difficult to swallow;
On the other hand, fish eggs and internal organs are highly toxic, and the processing and processing of fish scales and internal organs is more troublesome, and the nutritional value is not high, so it is not suitable for consumption. Poisonous crocodile eel eggs and offal can not be discarded casually, the best way is to bury it, so as not to pollute the water source.
In addition, alligator eels attack humans when frightened.
(The author is a master's student at the School of Life Sciences, Henan University)
【Author】 Huang Wenrui
Southern Review