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The Crayfish: From Invasive Species to Culinary Delicacy and Scientific Marvel

  Although crayfish is just a small shrimp, there are many customs and gossip surrounding it. Some say it is a domineering invasive species that has unfortunately brought down a big foodie country; others say it is a biological weapon developed by Japan to win the war and was cleverly used by the Chinese. This article will analyze the rumors about crayfish one by one for you.
  When summer comes, restaurants, barbecue stalls, and food stalls everywhere are often very busy. The “Internet celebrity” in the food world – crayfish will make its debut at this time every year, filling every night of drinking and drinking.
  Today, in many counties and cities represented by Jiangsu Xuyi, crayfish has become an important local economic pillar. Thanks to this, my country has become the largest crayfish producer and created an industry with a total economic output value exceeding 100 billion. In 2016, 879,300 tons of crayfish produced in China were eaten by the Chinese people. In addition, a large part of them left Asia and were exported to Europe and the United States, making them famous internationally.
  What is intriguing is that the “Made in China” version of crayfish that American friends have gone to great lengths to introduce is actually “born in the United States.”
  The origin of crayfish:
  Where crayfish come from, most Chinese people don’t know very well. Many people’s first encounter with crayfish often happens at the dinner table. They have only heard that this creature once lived in field ditches, swamps, wetlands, and turbid water in ponds. These small reddish-brown creatures are highly adaptable and can survive even in water bodies with excessive levels of heavy metals. Moreover, whether it is dead fish, rotten shrimps, or rotten trees and dead leaves, it accepts all comers without rejecting them.
  The reproductive capacity of crayfish is also quite amazing. As long as a few crayfish appear in the water, the entire water area will soon be completely occupied by crayfish. The crazy reproduction of crayfish not only squeezes the living space of other aquatic animals, but also damages crops and affects harvests.
  Except for farmers who specialize in crayfish farming, most farmers are eager to get rid of them quickly.
  Crayfish, as the Chinese know it, is actually an imported product—the enemies that could limit it have been left behind in their hometown. In the second batch of “China’s Invasive Alien Species List”, crayfish is among them. Its name is “Procambarus clarkii” and its origin is North America. The mouth of the Mississippi River is the home of crayfish.
  In the 1920s, under the operation of a group of Japanese, more than twenty crayfish crossed the Pacific and arrived in Asia, which they had never set foot on before.
  Why did the Japanese introduce North American crayfish? Common claims include bringing them home as ornamental species in aquariums or feeding bullfrogs. Unfortunately, the introduced North American crayfish escaped into the wild, encroaching on the Japanese crayfish’s habitat and taking its place.
  In 1930, the Japanese brought crayfish to Nanjing. The crayfish that successfully made the eastward journey became a small ancestor in the waters of China.
  There are several common theories about why Japan introduced crayfish to China. One of them is: crayfish are the product of genetic modification of American crayfish by the Japanese invaders, and are specially used to clean up the corpses of Chinese people. However, crayfish were introduced to China in 1930. The Japanese army’s criminal act of mass murdering Chinese people had not yet begun, and genetic modification technology was far from emerging. It is unclear why the Japanese introduced crayfish to China at that time. A more reasonable guess is that they were used as feed for bullfrogs.
  In China, only three species of crayfish exist in the northeast, and there are no similar species of crayfish in the waters west of Hangu Pass. After being introduced to Nanjing, North American crayfish took to the water like a fish in water and quickly expanded from Nanjing to all over the country. As an invasive species, this crayfish, which is extremely resistant to pollution and has the ability to reproduce, and lacks natural enemies, quickly became overrun.
  However, after 30 years of showing off in China, the natural enemy of crayfish finally appeared. That is, foodies!
  Debunking rumors for internet celebrities
  Whether in Japan or China, crayfish initially appeared as feed. Later history proved that the wishful thinking of using crayfish to raise bullfrogs failed. But while bullfrogs have little interest in crayfish, one species of primate has discovered its delicacies.
  Louisiana, the home state of crayfish, holds a Crayfish Festival every year. Since the 19th century, crayfish stewed with garlic, potatoes and sauce has become a favorite summer food of Louisiana residents. Of course, compared to the Chinese way of cooking crayfish, the way Louisiana residents cook it can only be considered entry-level.
  In the 1960s, the first crayfish entered the digestive system of the Chinese people and gloriously became the first invader to be exterminated.
  Over the next half century, the Chinese invented countless ways to cook crayfish. In Xuyi, Jiangsu, the most popular dish is the addition of thirteen incense; in Hubei, Qianjiang oil-braised prawns are famous far and wide; and in Hunan, spicy crayfish has become a local specialty. In addition, there are boiled, brine, minced garlic, salt and pepper… No matter which way you eat it, there are many loyal fans, and crayfish has truly become “popular” in China.
  However, shrimp red has a lot of right and wrong. “Crayfish live in sewage, and the heavy metal content exceeds the standard!” Such reports have gradually become more popular as crayfish become popular.
  In fact, it is difficult for people to gain excess weight and metals by eating crayfish. Once heavy metal pollutants enter the body, they are difficult to eliminate, but crayfish have a solution. It can concentrate heavy metals in their shells. As an animal that constantly sheds its shells, crayfish can effectively remove heavy metals by throwing off their shells. Excrete heavy metals ingested.
  What’s more, crayfish don’t really like polluted water bodies, but prefer to live in clean water bodies. The Chinese people’s enthusiastic demand for crayfish has made the supply of crayfish, an invasive species that was once rampant, in short supply. Large-scale artificial breeding is required to meet this huge demand. Artificial breeding must have quality inspections, and the possibility of excessive heavy metal intake is probably very small. If the shell, gills and shrimp threads are removed and only the shrimp meat is eaten, the possibility of excessive heavy metal intake is extremely small.
  Crayfish meat is tender, rich in protein, and easy to digest. It is not a problem even for people who are weak or have just recovered from illness. At the same time, crayfish meat is rich in magnesium, which can well regulate heart activity, lower cholesterol levels, prevent arteriosclerosis, expand coronary arteries, and has a certain preventive effect on cardiovascular and cerebrovascular diseases. In addition, shrimp meat can stimulate lactation, so it is good for pregnant women to eat some of it. The astaxanthin in it also has good anti-aging and anti-cancer effects.
  Crayfish is not only a celebrity on the dining table, but it is also likely to show its talents in the laboratory in the future – it is an animal that can regenerate nerves.
  Generally speaking, as higher mammals, human nerve cells are difficult to regenerate. But crayfish can convert their own blood cells into neurons, restoring and supporting visual and olfactory circuits. In other words, its nerve pathways can repair themselves after being cut off. It is precisely because of this magical skill that crayfish can be used in human nerve regeneration research, providing new ideas for the development of brain neuroscience.
  Whether it is nourishing the public with its body or dedicating its body and mind to scientific research, the crayfish has benefited us in many ways and deserves all-round recognition from mankind.