Recently, Yunchan Lake in the Central Park of Ruzhou City, Henan Province, was drained. Why drain Yunchan Lake?
It is reported that Yunchan Lake began to use pumps and other facilities to pump water from July 26, and pumped 200,000 to 300,000 cubic meters of lake water in a full month, and the amount of engineering is very large. However, how could such a painstaking effort drain a lake for a fish?
It turned out that just a month ago, according to the citizens' feedback, a "strange fish" appeared in Yunchan Lake, not only large, but also haunted, according to witnesses, this "strange fish" body length is about 70 to 80 centimeters. Citizens who are accustomed to seeing carp and other ornamental fish have speculated that it is a bluefish or a giant catfish. Later, experts judged according to its characteristics that it was highly suspected of high-risk alien crocodile eels.
This matter has been reported, and immediately attracted the attention of the Ruzhou Municipal Party Committee and Municipal Government, and the related matters of fishing crocodile eels were launched, but due to the very large area of Yunchan Lake, it was salvaged for many days without effect. It was finally decided to use pumps and other facilities to drain the water from Yunchan Lake from July 26 and identify these high-risk alien species, the crocodile eel, in order to prevent the invasion of this alien species.
So why is the discovery of alligator eels so nervous, and what harm will high-risk alien organisms cause?
Alligator eel
Let's first get to know the alligator eel, a freshwater giant carnivorous fish that is a specialty of southern North America, a prehistoric fish that has lived on Earth for more than 100 million years. Crocodile eels, though steeped in history, are particularly unpopular.
First of all, it grew up to be unloved, at first glance like a ferocious crocodile, and the upper and lower rows were covered with sharp teeth. It is also because of this that it can swim in a water area with ease.
In addition, its habits are not popular, and the alligator eel is a giant freshwater carnivorous fish that feeds on fish in the waters. Fishermen are even more intimidated by it, because once it enters a closed water, the crocodile eel can eat other fish without predators.
In 2021, the owner of a fish pond in Ganquan County, Shaanxi Province, found that all the fish and shrimp in his fish pond had disappeared, and in order to figure out what was going on, he drained the fish pond and finally found a one-meter-long crocodile eel, which can be said that the fish in the entire fish pond were eaten by the crocodile eel. The meat-eating habits of the alligator eel also give it a certain degree of aggression, and even has the danger of harming humans. Some time ago in Taizhou, Jiangsu Province, a boy was playing in the landscape pool of the community and was bitten by a "strange fish" and injured 3 fingers. The boy's parents said that the wound was bitten and bleeding, and there were 6 or 7 scars on it, about 1 centimeter. After passing through the community property and residents, the landscape pool was immediately pumped, and a crocodile eel up to 70 centimeters long and weighing more than 10 kilograms was found.
For our Chinese, the value of alien species depends to the greatest extent on whether they can be eaten. There are many popular exotic species on the table, such as protocell shrimp, that is, crayfish, and bullfrogs. Therefore, a big reason why the crocodile eel is not welcomed is that it cannot eat, first of all, its skin is thick, the scales are large and hard and difficult to handle, and it will scratch the hand if it is not good.
Second, the alligator eel is a top poisonous fish, and like the pufferfish, it can produce highly toxic substances during ovulation, and people will be poisoned after eating a few bites, even endangering their lives. For example, crocodile eels and California perch entered Guangdong as exotic species at the same time, but the California perch was tender and conquered by the cantonese who loved food before it was flooded. But the crocodile eel seems to be a different kind, so that the annual consumption of this aquatic product is close to 1,000 tons in Guangdong Province, and there is no choice.
What are the consequences of allowing alien species to invade?
The alligator eel is a ferocious carnivorous fish from southern North America that can swallow up to nearly 1/4 of its body weight. Hungry alligator eels, while swallowing to replenish energy, excrete feces. Digesting dozens of pounds of freshwater fish a day, for a closed freshwater lake or artificially farmed fish pond, it can be said that it is easy to eliminate other fish. After asian carp entered the United States as an exotic species in that year, it was flooded due to its strong fertility and the local people's dislike of eating. Overwhelmed, the Americans finally came up with a big move, using alligator eels to deal with Asian carp.
Therefore, the alligator eel is also known as the "freshwater killer" and is listed on the list of "the world's top ten freshwater carnivorous fish". On the mainland, there is currently no natural enemy of the alligator eel, and in order not to flood it in the continental waters, we can only curb the reproduction of the alligator eel from the root, because we cannot introduce an alien species to contain another alien species.
The harm of alien species invasion has three aspects, one is to cause a decline in agricultural and forestry products, output value and quality, and increase costs.
The second is to have an impact on biodiversity, especially by encroaching on the living space of native species, resulting in the death and endangerment of native species; The third is the impact on the health of people and livestock and trade.
According to the IUCN definition, an alien species is a population established in natural and semi-natural ecosystems and habitats, and when it alters and endangers local biodiversity, it is an invasive alien species, and the harm it causes is an alien invasion. According to statistics, at least 188 invasive plants, 81 invasive animals, and 19 invasive microorganisms have been found on the mainland; Of the 100 most threatening invasive alien species in the world, published by the International Union for Conservation of Nature, 50 have been found on the mainland, causing serious harm to agriculture, forestry, water conservancy, animal husbandry and so on.
How did the alligator gar enter China?
Although the crocodile eel is not popular with people, humans just like strange things. For a long time in the past, the alligator eel was only distributed in the tropical and subtropical regions of North America, so it is an exotic species for us. In the 1980s, with the opening up of foreign economic relations and trade, crocodile eels were introduced into the country as ornamental fish. At first, it was still farmed, but it was inevitable that there would be fish that slipped through the net. It flows out of the wild from the breeding base or is artificially purchased for breeding and released. At present, one of the main means of dispersal of alien species is release.
The strange appearance of the alligator eel makes some fish lovers interested in it, buy it home and raise it in the bathtub, and finally find that the crocodile eel is not only expensive to raise, because it eats meat. And the older they get, the bigger they are, the less suitable for home fish tanks, and eventually they are released casually. However, due to insufficient knowledge and cognition, the habits of alligator eels and the harm of alien species invasion lead to their random release in a water area. The consequence of this is that the loss of human and material resources has even affected the property safety of some people.
Release requires caution, a mistake that has been hated for eternity
Why can't wild animals be released at will? The starting point of releasing purchased and rescued wild animals into the wild environment is good, but it will bring many problems, and even cause serious consequences and suspected of violating the law. For released wild animals, if released to an environment that is not suitable for living, they may die due to inability to adapt. Let's look at two examples:
Cases of death of released species; In 2021, the report of the release of crocodiles in the Jingniang Lake Scenic Area of Wu'an City, Hebei Province, has attracted widespread attention and has also attracted the attention of relevant departments. After receiving the report, Wu'an City immediately organized a professional team to carry out emergency fishing work. After on-site inspection by professional animal breeders, it was confirmed that the crocodile was dead. According to preliminary judgments, the crocodile was farmed in captivity, and due to continuous rainfall and temperature drops in recent days, it could not adapt to the wild aquatic environment and caused death. Crocodile carcasses will be disinfected by the forestry department in conjunction with professionals and then buried for deep burial.
Cases of release of alien species; In 2016, Guangdong News reported that a man surnamed Dong, because he was not accustomed to seeing crocodile turtles being slaughtered as food, bought a crocodile turtle for 500 yuan in the aquatic market, and then took it to the wild to release, resulting in disaster in the local rural areas. Crocodile turtles have a habit of feeding on algae and benthic animals. However, do not polyculture with mild or small fish. If it multiplies in large quantities, it will devour other fish eggs, leading to the extinction of other fish. There are no natural enemies in China. Do not release.
Finally, let's give everyone a wake-up call; According to the Law of the People's Republic of China on the Protection of Wild Animals (Revised Edition), it is clear that any organization or individual who releases wild animals into the wild environment shall select local species suitable for wild survival in the release site, and shall not interfere with the normal life and production of local residents to avoid causing harm to the ecosystem. Where wild animals are released arbitrarily, causing personal or property damage to others or endangering the ecosystem, legal responsibility is borne in accordance with law.
When releasing, we must understand clearly the habits of the species and whether the release waters will cause harm, avoid unnecessary trouble, and regard it as a good result of their own good deeds.