Fish has always been a delicacy on the Chinese table. Since ancient times, Chinese have loved to eat fish. Because fish and "Yu" are harmonious, on the evening of Chinese New Year's Eve, there must be a fish dish in the Chinese New Year's Eve meal, which symbolizes the annual surplus. Chinese take the fish as a big dish, one is to be auspicious and lucky, and the other is that the fish is really delicious and nutritious.
Therefore, China's fish farming industry has been expanding its development scale. In 2020, the annual output of aquatic products has exceeded 65 million tons. Even in tibetan areas where fish are regarded as "dragon gods' pets" and do not like to eat fish, fish farming has gradually developed. In Yangzhuo Yongcuo, there are a large number of freshwater fish, which are even enough for people all over China to come to a kilogram a day.
But food on the Chinese table, when it comes to the United States, has become a disaster. The United States is agonizing over the proliferation of Asian carp every year, and what is the cause?
<h1 class="pgc-h-arrow-right" data-track="4" > Asian carp </h1>
Asian carp is a collective term for carp, bluefish, grass carp, silver carp, crucian carp and salmon. These fish are very common in China. Bluefish are basically farmed in the plains south of the Yangtze River, and the dorsal fin of the bluefish is above the ventral fin, there is no hard spine, the whole is blue-gray, the abdomen is relatively white, and the fins are black. This fish is adapted to grow at a water temperature of about 25 degrees Celsius, so the north of the Yangtze River is not suitable for the cultivation of bluefish due to the cold water temperature. Bluefish is one of the four major fish cultured in Freshwater in China.
Grass carp is distributed in the Three Water Systems of the Yangtze River, pearl river and Heilongjiang River. Grass carp are yellow overall, the dorsal fin has no hard spines, it is grayish yellow, and the abdomen is grayish-white like that of bluefish. Similarly, grass carp is also one of the four major fish in freshwater aquaculture in China.
Bighead carp, because of the characteristics of filter feeding, often eat some zooplankton and phytoplankton, so it is called Rudolph in the water, and is often used as a fish that purifies water quality.
Carp is very common in rivers, lakes and reservoirs, and because of its adaptability and endurance, carp is widely distributed, the number of fish is the largest, and it is the longest cultured fish in the Chinese.
Silver carp is loved by Chinese because of its delicious meat and rich nutrition, this large freshwater fish not only grows fast, but also has high yields, and what is more valuable is that silver carp rarely gets sick, which is one of the most important economic fish in China.
<h1 class="pgc-h-arrow-right" data-track="10" > why childhood cannot be lived in China </h1>
Although these fish are all economic fish in China, they have a hard time surviving childhood for two reasons: overfishing and pollution of rivers such as the Yangtze River.
Although there are many Asian carps living in China, there are also many Chinese populations. China is the world's most populous country, and every family loves to eat fish, which has led to a particularly large demand for fish in China.
carp
The sheer demand has prompted fishermen to go out to fish regularly, as the number of farmed fish is already somewhat in short supply. Although the state explicitly prohibits fishermen from fishing during the fishing ban period, fishermen still choose to go out to sea to catch fish in order to make a living. In this case, many fry that have not grown and developed have also been caught by fishermen, which has led to the inability of Asian carp to survive childhood in China and not grow too long.
Secondly, the pollution of the Yangtze River has also led to a significant reduction in fish populations, because of industrial wastewater discharge, as well as ship pollution, fish living in the Yangtze River can not adapt to this dirty environment, most of the fish began to die.
Wastewater discharge
Overfishing and industrial pollution have led to a dramatic reduction in the number of wild fish in places like the Yangtze River, and even experts have become wary, calling on people to "be merciful" and prohibiting fishermen from illegally fishing fish.
Illegal fishing is extremely harmful to biodiversity
<h1 class="pgc-h-arrow-right" data-track="16" > flood in the United States </h1>
Why is this kind of fish that cannot live in China for childhood flood in the United States? This is because in the 1960s, aquatic plants such as algae in freshwater lakes in the United States flooded, and these harmful algae caused the aquatic organisms in the lake to suffocate and die, and the crazy growth of algae stole oxygen from the lake.
In order to control the continued flooding of algae plants, the United States has chosen to use biological control methods and introduced a large number of Asian carp.
The introduction of Asian carp in large quantities did play a role, and the algae food floating in freshwater lakes in the United States was eaten by Asian carp. But another problem arises – the Asian carp has become an invasive species.
Asian carp fat into pigs
Because the Asian carp is very adaptable and resistant to life, coupled with the fact that there are no natural enemies in freshwater lakes, Asian carp breeds wildly in freshwater lakes in the United States. The introduced Asian carp swims upstream along the Mississippi River Basin, breeding and invading in various waters, and native local fish have been robbed of their territory by the overlords of this fish.
And because Asian carp is very edible, the food of local fish has been robbed by Asian carp. In just over a decade, the population of native fish has plummeted, and Asian carp has disrupted the local ecological food chain and seriously affected the fishing economy. The United States lost more than $18 billion to Asian carp. In the 1980s, the United States officially designated the Asian carp as an invasive species.
In the freshwater lakes of the United States, the wanton growth of Asian carp can weigh up to 45 kilograms, which is simply the giant of the fish. For a while, the United States could not solve this uninvited guest.
Big Mac of Fish
First of all, because Americans do not have the habit of eating Asian fish at all, Asian fish species always have a dirty smell, and american cooking methods cannot get rid of this unpalatable earthy smell, and Americans use knives and forks, Asian fish species are thorny, knives and forks can not eat thorny fish well.
Secondly, because Asian carp was not originally introduced for food, it was to make Asian carp a scavenger in the water. At this point, the Asian carp is a perfect task, and the harmful algae in the water are all in the belly of the fish. But this also creates a problem, the toxic toxins of harmful algae accumulate in the flesh of the fish, people can not put their mouths down, it is likely to be diarrhea or food poisoning due to eating Asian carp.
Algae also contain parasites
<h1 class="pgc-h-arrow-right" data-track="25" > biological invasion </h1>
The proliferation of Asian carp in the United States is typical of biological invasions. Biological invasion refers to a certain organism that lives in the original place of existence, due to natural or human factors, this plant or animal invades a new environment, and this invasive species causes harm to the local biological diversity.
Biological invasions can cause a lot of economic losses due to the destruction of the local agricultural and animal husbandry economic system, and cause indelible disasters to the local nature.
In the concept of biological invasion, invasive species are all alien species, but alien species are not necessarily invasive species. Invasive species specifically refer to alien harmful species, and those species that are beneficial to human introduction, such as carrots and peas introduced in China, are not considered invasive species.
Rolling tumbleweed that drove America crazy
Therefore, only those alien species that destroy local biodiversity and cause economic losses can be called invasive species. The right introduction of species increases the local biodiversity.
No one can guarantee that the right species will be introduced every time, and in many cases, humans will "misjudge" the species introduced. Many species were very good cash crops before they were introduced, or they were beneficial to the protection of the environment.
For example, rice grass, before the introduction of this plant in China, this plant was high-quality animal feed in the place of origin, and in European industry, rice grass can be used as fuel and paper raw materials. Even Europeans would use it as green manure to make the land more fertile.
Rice grass
But it is the seemingly harmless rice grass that has become an invasive species in China. Rice grass has no natural enemies in coastal areas, and this plant is alkali-tolerant and live-resistant, and has a strong reproductive ability, so it grows wildly on the coast. The flooding of rice grass induces red tides, causing many marine life to suffocate to death, and rice grass also steals nutrients and oxygen from native plants, becoming the plant overlord of the coastline.
This has led to the decline of our fishing industry, and because the rice grass grows too fiercely, the boats that come and go are occasionally entangled in the rice grass, which makes our navigation very inconvenient.
The introduction of Asian carp in the United States is also the same biological invasion induced by the wrong introduction, which was originally used to clean up the algae-flooded Asian carp, but because there is no natural enemy and the high-quality environment of freshwater in the United States, the number of Asian carp has surged, which has greatly affected the US fishery.
Fat into piglets
Another case is unintentional introduction. Humans originally wanted to introduce other good species, but this invasive species mixed in with this introduced species. For example, tumbleweed in the United States, that is, when Russia imported flaxseeds for oil extraction to the United States, it entered the Americas with the seeds of flaxseeds. Nowadays you can see tumbleweeds everywhere, and tumbleweeds have become an iconic invasive species in the United States.
<h1 class="pgc-h-arrow-right" data-track="36" > biological invasion control </h1>
When it comes to the control of invasive species, people's first thought is to eat control, as long as the invasive species are eaten, there will be no problem. But this idea of eating does negate the results of researchers who have successfully controlled biological invasions.
There has never been any invasive species that can be solved by foodies, and people who say they want to eat all the invasive species on the Internet will not really eat it. The book "Chinese Geographical Magazine" wrote that the species introduced in China: tilapia, the meat is tender, the taste is delicious and the thorns are few, and it is recommended to introduce it. But what is the end result? This species of tilapia floods in large and small freshwater rivers in southern China, and no one has been seen to eat the tilapia that has become a disaster.
Tilapia
If you want to control invasive alien harmful species, you can't simply eat it. Many times, it has to go through the long-term research of researchers. At present, there are two main ways to control invasive organisms, one is to find chemicals that can curb the growth of invasive organisms, which is chemical control, and the other is to control by introducing natural enemies.
But the introduction of natural enemies will cause another problem, that is, it is possible that the natural enemies of this invasive organism will eventually become an invasive organism, and the introduction of Asian carp from the United States is the best example. Therefore, if you want to really control biological invasion, you must carry out chemical control and biological control at the same time, so as to be efficient.
The delusion of eating is naïve and ignorant, and it is also harmful to the world's scientific researchers who are struggling every day to deal with invasive organisms.
<h1 class="pgc-h-arrow-right" data-track="42" > conclusion </h1>
Today, the Asian carp in the United States is still flooding in the freshwater lakes of the United States, and the United States itself has thought of ways to remediate this invasive species, but unfortunately with little success. Although the Asian carp, which is still a native fish in the United States, has become edible after decades of breeding, Americans are still reluctant to eat this fish.
The United States has also thought of a way, the U.S. government has electrocuted the fish in a freshwater lake with electric shocks, but this method does not cure the symptoms, in this lake, not only the existence of Asian carp, the original native fish also died of electric shock. After the fish are dead, they still reproduce faster, and the Asian carp, the overlord of the fish without natural enemies, will reoccupy the waters.
Densely packed Asian carp
Biological invasion has become a worldwide concern, and in this era of global economication, biological invasion has become an unavoidable thing. More delicate control at the customs and the inadmissibility of organisms are the best means to prevent biological invasion.