The process or phenomenon in which an organism is transmitted in any way to a country or area other than its place of origin and colonizes there to establish a natural population expansion and exert a certain impact is called bio-human infestation, which is currently one of the most serious threats to ecosystems such as forests, grasslands, farmland and water systems.
The number of invasive species in China has reached 529 species, of which terrestrial plants, terrestrial invertebrates and microorganisms are the main invasive tax groups, and Guangdong, as the most important international trade port in China, is also one of the most harmful areas of biological invasion in China. According to statistics in 2009, the number of invasive species in Guangdong exceeded 200 species and the number of invasive plants exceeded 90 species. At present, vinifera, trifolium chrysanthemum, acacia, water hyacinth and lantana have blossomed everywhere in Guangzhou.
Among the organisms that invaded Guangdong, there are also North American giant fish, crocodile gar, as China's most fish-loving province, Guangdong's annual aquatic product consumption exceeds 7 million tons, why can't it be alligator eel?
<h1 class= "pgc-h-arrow-right" > what is a crocodile gar</h1>
Alligator eel is a species of finches, finches, and large finches, because the alligator eel is full of hard scales, and has a long mouth full of sharp teeth, which is indeed somewhat similar to crocodiles, so it is named crocodile eel.
Fossils of the Cretaceous gar in Europe over 120 million years have been found, so it is also known as a "living fossil" in fish. At that time, the species of finches was very diverse, almost all over the world's waters. But now this ancient fish is no longer thriving, only crocodile eels and 6 other species of gar.
Alligator eels can grow up to 3 meters and weigh 45-72 kg, and females are said to grow up to 6 meters. It is found in the gulf coastal rivers and estuaries from Mexico to Florida, the lower Missouri and Ohio rivers, and even two lakes in Nicaragua.
They are a kind of carnivorous fish, crocodile eel is and "piranha pomfret" the same name of the "world's top ten freshwater fierce fish", also known as "freshwater killer", crocodile eel does not have the function of chewing, they can only eat by swallowing, the largest can swallow 1/4 of the body's food, mainly feed on other fish, they can eat while defecating, larger crocodile eels can eat dozens of pounds of freshwater fish a day.
Because it is too edible, the waters inhabited by the alligator eel are rarely found in other fish species. In the United States, because there are natural enemies, such as alligators, the recipe of alligators includes juvenile alligators, so in order to ensure the survival rate of juveniles, adult alligators will attack alligators. Hunt juvenile alligator eels.
Coupled with the mass slaughter of humans, the alligator eel is endangered in its hometown and is now listed as an endangered animal by the American Zoological Society. But in China, the alligator gar can be said to live very moist.
< h1 class="pgc-h-arrow-right" > crocodile eel invaded Guangdong</h1>
Crocodile eels have been introduced to China as ornamental fish since the 1980s, in the process, there will be escape to natural waters, of which they have been found in many places in Guangdong, and caused a sensation, as early as 2014, Guangdong has investigated that there are 21 areas of this crocodile eel, and some places have formed wild alligator eels. In the past two years, crocodile eels have also begun to invade other provinces.
Crocodile eel in addition to can eat, especially good to feed, it not only eats everything, and its vitality is tenacious, can live for more than 25 years, if the environment is very comfortable, you can even live to 75 years old, they are not picky about water quality, even freshwater or saltwater ecology can survive, can also breathe air, leaving the water can still persist for at least two hours without dying.
Crocodile eels also have the common characteristics of all invasive organisms, that is, they are super reproductive, females lay 140,000-200,000 eggs at a time, and crocodile eel eggs are toxic, which is the survival secret they evolved to protect their eggs.
As a carnivorous fish, the alligator eel is extremely destructive, and if it is placed in natural waters, it will bring ruin to the local water ecosystem, "as long as it is a living thing in the water, it is almost all-consuming.". If there are 1-2 such fish in a pond or cultured water, all the fish raised in the pond can be eaten.
<h1 class= "pgc-h-arrow-right" > why Cantonese people can't get crocodile eels</h1>
The main reasons why Cantonese people can't get crocodile eels are as follows:
1, crocodile eel is poisonous; can be called the top poisonous fish, and puffer fish, in the ovulation period can produce highly toxic substances, people eat a few bites will be poisoned, even life-threatening, and their internal organs are also poisonous, when eating to remove clean. It is difficult to deal with alligator eels if they are non-professionals.
However, during the non-ovulatory period, alligator eels can be eaten, and in the southern United States, fried garnet balls and grilled fish fillets are more popular dishes.
2, crocodile eel meat quality is poor, processing is difficult; but their meat taste is very poor, the meat is very chai, it grows hard scales all over the body, like wearing steel helmet and iron armor, with strong defense, processing trouble, to use an axe to cut open, which is why even the Cantonese who love to eat fish, do not like crocodile eels very much.
3, crocodile eel is very aggressive, it is difficult to catch; gar is introduced to China with ornamental fish, the size of the gar raised in the aquarium is very small, but the stocking of wild waters, because there is no natural enemy so it will be more and more large, a person if found in the wild crocodile eel, it is difficult for a person to catch it, like Guangdong Zhaoqing found the crocodile eel, several people with fishing nets can not get the crocodile eel, and finally the police spent 15 minutes to pull the big fish ashore.
The crocodile eel was found in The South China New Town of Nancun Town, Panyu District, and several people could not catch it until the security guards pumped water overnight to salvage it, and under the joint encirclement and suppression of several security guards, they caught the evil fish in the mud of the lake and dragged it ashore, even so, the security guard was slightly injured. It can be seen from here that if alligator eels are found, the cost of catching them is very large.
In addition, the alligator eel may hide in the water day or night under driftwood, debris or hanging branches on the surface of the water to remain stationary, which makes it difficult to find its tracks.
According to statistics, there are 345 rivers with a catchment area of more than 100 square kilometers, of which 38 are rivers with a catchment area of more than 1000 square kilometers. These rivers belong to the Pearl River, the Han River, the east coast of Guangdong and the coastal system of western Guangdong. Coupled with the fact that Guangdong belongs to the subtropical monsoon climate and high temperature throughout the year, it is very suitable for the breeding and development of crocodile eels, and then forms a wild population, which is why crocodile eels are found in as many as 21 regions in Guangdong.
Combining these factors, this is also the reason why Guangdong people can't get crocodile eels, so that crocodile eels flood into disaster.
According to incomplete statistics, since the introduction of Mozambican tilapia in 1957, About 150 species of exotic aquatic organisms have been introduced in China. In addition, with the development of recreational and ornamental fisheries, a variety of foreign ornamental fish have also been introduced to The country in large quantities.
There are many fish that are discarded and released at will, which eventually leads to biological invasion events and causes great damage to our ecology, and the alligator eel is the most typical example.
But in the United States, the American people have discovered a use of alligator eels, that is, to eat Asian carp, Asian carp in the American rivers to live freely, very comfortable, because of the excellent living environment, fat as pigs, often fifty or sixty pounds. The United States thought of many ways, but did not get the Asian carp, which reminded it of the endangered crocodile eel and wanted to borrow its power.
Finally, I hope that everyone will not be artificially released and discarded at will; breeding needs to take strict anti-escape measures, which will cause very serious consequences; dear Guangdong Liangzai, if found in public waters, special fishing should be carried out immediately, wild bycatch should be harmless treatment, and should not be put back into the original waters