1. The history of crayfish

Crayfish originated from Louisiana in the south of the United States, an animal in saprophagous, and entered China with biological invasion ways such as ballast water of foreign freighters in the early 2th century.

Because natural enemies have not yet formed in China, after decades of diffusion, they have formed the most common freshwater economic shrimps in China, which are widely distributed in the middle and lower reaches of the Yangtze River. The content of protein in crayfish is high, accounting for about 16%-2% of the total, and the content of fat is less than .2%. The content of trace elements such as zinc, iodine and selenium in shrimp meat is higher than that in other foods.

However, a very important nutrition of crayfish may be overlooked by many people, that is, astaxanthin, which mainly exists in the yellow of shrimp head and the red substance on shrimp shell. Most cooking methods may be lost, because astaxanthin is a strong antioxidant, so it is easily oxidized. In addition, crayfish can also be used as medicine, which can eliminate phlegm and relieve cough, and promote the wound healing after operation.

China didn't produce crayfish in the past, but crayfish should have been introduced to China from the United States via Japan in recent decades. However, except for China, Japan, the United States and other countries do not use crayfish for food. The main purpose of Japanese national crayfish is to clean up river corruptions. It is a good tool for river cleaning and will not bring secondary pollution.

2. When did China people start eating crayfish

In the 193s, some Japanese biologists brought crayfish to the coastal areas of China, where they first naturally propagated and expanded, and then entered Hubei in 1974.

In the popular rumor, the story that the Japanese brought crayfish to China is as follows:

The biochemical troops of the Japanese army stationed in China changed crayfish into crayfish through a series of genetic modification because they had to deal with a large number of corpses, and transported them to the Japanese army station to take up the work of cleaning water.

First of all, it was well known that the Japanese invaders were inhuman at that time. How could he have thought of disposing of the bodies in such an environmentally friendly way?

Secondly, this remark can't stand scrutiny. It was not until 1953 that Watson and Crick discovered the double helix structure of DNA, and it was not until the 197s that human beings began to study the application of DNA recombination technology. At that time, how could the Japanese invaders have such technology and genetically modify crayfish? !

In fact, the crayfish brought to China by the Japanese at that time were still prepared as bait for bullfrogs.

In fact, there are four original authentic crayfish in China: Northeast Black Crayfish, Nanjing Black Crayfish, Procambarus schrenckii and North Korean Black Crayfish. Among the "foreign monks", not only Procambarus clarkii originated in the United States, but also red crayfish originated in Oceania, but Procambarus clarkii is superior in technology and has blossomed everywhere in China, becoming the most famous crayfish. This "foreign monk" is really "fond of chanting scriptures". Because of its strong reproductive ability and adaptability to the environment, it has completely affected the status of native species.

In the 198s, freshwater crayfish, a night food stall near Zhongshan Fifth Road in Guangzhou, was introduced to China in the 193s, but its edible and disciplinary research history was after the 196s. In 1983, Dai Aiyun, Institute of Zoology, Chinese Academy of Sciences, advocated the development and utilization of freshwater crayfish as an aquatic resource for the first time. At the same time, the School of Fisheries of Huazhong Agricultural University and Hubei Institute of Fisheries Science began to develop Procambarus clarkii.

In the early 198s, Guangzhou Bureau of Landscape Architecture, Pearl River Fisheries Research Institute of China Academy of Fisheries, Hubei Fisheries Bureau and Hubei Fisheries Research Institute successively introduced crayfish from Australia for trial culture. In 1988, Hubei Institute of Fishery Science took the lead in breeding crayfish in China, which was the first successful breeding of crayfish in the northern hemisphere and attracted worldwide attention.

In 1991, Hubei Fisheries Research Institute took the lead in introducing red-clawed shrimp to Australia for trial culture in China. In 1992, it was successfully bred in Hubei and Guangdong, and it was popularized throughout the country. After the mid-199s, Hubei, Jiangsu, Anhui and other provinces in China explored the culture of freshwater crayfish for the second time. After 2, Jiangsu, Anhui, Shanghai, Hubei and other provinces in China have carried out artificial breeding of Procambarus clarkii. 3. the origin of crayfish

Procambarus clarkii is the most widely distributed alien invasive species in crustaceans. Procambarus clarkii

has an absolute competitive advantage in the local ecological environment because of its omnivorousness, fast growth and strong adaptability. Its feeding range includes aquatic plants, algae, aquatic insects, animal carcasses, etc. When food is scarce, it also kills each other. Procambarus clarkii can endure the dry season as long as four months, and can also adapt to the brackish environment where the brackish water meets in the estuary. In rainy season, Procambarus clarkii can migrate several kilometers to find new habitats. When feeding, you can use its strong claws to cut off the tender stems of plants; Procambarus clarkii has become an important economic breed in China in recent years. In the process of commercial farming, we should guard against escape, especially into the untouched original ecological water body. Its destructive harm to the ecological competitive advantage of local species has been widely reported all over the world, which should arouse our great attention. Crayfish are native to saprophagous, Louisiana in the south of the United States, and entered China in the early 2th century with the biological invasion of foreign cargo ships such as ballast water. The so-called creature used by the Japanese to clean up the dead bodies is false. At that time, the Japanese raised crayfish as bait for breeding in Niu Wa (but there are data showing that it was brought into Nanjing by the Japanese in the late 193s. See China Biological Invasion Research Science Press Wan Fanghao, Guo Jianying, etc.). Because natural enemies have not yet formed in China, after decades of diffusion, they have formed the most common freshwater economic shrimps in China, which are widely distributed in the middle and lower reaches of the Yangtze River. The content of protein in crayfish is high, accounting for about 16%-2% of the total, and the content of fat is less than .2%. The content of trace elements such as zinc, iodine and selenium in shrimp meat is higher than that in other foods. However, a very important nutrition of crayfish may be overlooked by many people, that is, astaxanthin, which mainly exists in the yellow of shrimp head and the red substance on shrimp shell. Most cooking methods may be lost, because astaxanthin is a strong antioxidant, so it is easy to be oxidized. In addition, crayfish can also be used as medicine, which can eliminate phlegm and relieve cough, and promote the wound healing after operation. Crayfish has a very strong viability. Besides Japan and China, Europe and Africa also occupy its territory, so it has become a world-class invasive species and a world-class delicacy. In Europe, Africa, Australia, Canada, New Zealand and the United States, people eat crayfish. Louisiana in the United States claims to produce 9% of the world's crayfish, and locals eat 7% of them. The "success" of crayfish in the world is partly attributed to its tolerance to polluted environment, except for some advantages in morphology and habits. In scientific research, organisms that are very sensitive to pollutants or very tolerant are often used as indicators of whether the environment is polluted or not. Crayfish is such a potential indicator. Some people on the Internet are afraid of hearing that crayfish is an indicator organism that pollutes the environment. It should be specially reminded that indicator organism and enrichment organism are two different concepts. Even an organism that is very tolerant of pollutants may have a very low pollutant content if it has a good mechanism of discharging and reducing toxicity. As early as 1995, researchers in Shanghai investigated the content of heavy metals in crayfish living in some parts of Shanghai, considering that crayfish like to live in shallow mud, which is easy to accumulate heavy metal pollutants. Mercury, copper, lead, zinc, cadmium and other heavy metals have been detected in crayfish, but all of them are lower than the national hygiene standards, and most of the heavy metals are concentrated in shrimp gills and viscera, and the content of muscle is very low. This result has been further proved in the following ten years of continuous research. In 23, researchers from Suzhou University investigated crayfish in Suzhou and got similar results. In 26, researchers from Jiangxi Agricultural University investigated the heavy metal enrichment of crayfish in heavy metal polluted water, and also found that there were few toxic heavy metals such as cadmium and lead in shrimp muscle, and relatively less harmful heavy metals such as zinc and copper were selectively enriched (zinc and copper are essential mineral elements for human body, but excessive intake also poses health risks). In 28, researchers from Anhui University investigated crayfish near Hefei, and also found that the heavy metals in chitin exoskeleton and viscera were higher than those in viscera. It was speculated that the heavy metals were transferred to the shell of Procambarus clarkii, and then the toxins were transferred out of the body by constantly molting, which was one of the reasons why it could tolerate heavy metal pollution. Interestingly, a middle school student in Shanghai, together with a scientific research unit, studied the authenticity of crayfish "spitting" heavy metals. She found that some vendors raised crayfish themselves for a period of time, and then claimed that the pollutants in their bodies had been "vomited" and they were safe to eat. So through market sampling, and designed an experiment to investigate. Her research shows that the contents of heavy metals cadmium and chromium in cooked crayfish are on the national standard line, and the so-called thing that clean water can "spit" heavy metals is also an unbelievable thing. Generally speaking, although crayfish have a certain ability to enrich heavy metals, most of them are concentrated in shrimp gills, viscera and shrimp shells that we don't like to eat. For those of us who eat shrimp meat, it is very unlikely to cause heavy metal poisoning. 4. What is the origin of crayfish? < P > There are rumors on the Internet: "The Japanese biochemical troops stationed in China have transformed crayfish into crayfish through a series of genetic modifications because they have to deal with a large number of corpses, and transported them to the Japanese military station. This theory of

is quite absurd. In 1953, Watson and Crick discovered the double helix structure of DNA, and in the 197s, human beings began to study the application of DNA recombination technology. It was simply impossible for the Japanese invaders to engage in genetic modification.

However, the crayfish we are eating now are really from Japan. In 1927, Japan introduced 2 Procambarus clarkii from the United States, in order to breed and cultivate them as feed for bullfrogs. Around 193, Procambarus clarkii < P > was introduced to China again, and the earliest breeding place was near Nanjing, which was probably also used as feed. After that, Procambarus clarkii thrived everywhere with its good adaptability. So in terms of time, crayfish's entry into China has nothing to do with Japan's invasion of China, and there is no conspiracy theory. -shell net 5. How long has crayfish been in Beijing? < P > Crayfish was introduced to China by Japan during World War II, but it is not clear whether it is used to dispose of corpses. The scientific name of crayfish is crayfish, also known as red crayfish? Or freshwater crayfish. Crayfish belongs to a large family of arthropods, and belongs to crustaceans together with lobsters, crayfish, crabs, shrimps and prawns.

Professor Cai Shengli from the School of Fisheries, Shanghai Fisheries University introduced that crayfish is an out-and-out "exotic product". Crayfish, native to North America, is an important species of freshwater shrimp culture in the United States. In 1918, Japan introduced crayfish from the United States as bait for raising bullfrogs, and crayfish proliferated and spread in a large area in Japan. During World War II, crayfish was introduced into China from Japan and began to breed in Nanjing and suburban counties of Jiangsu Province. After a long period of expansion, the population increased and the living space expanded. Now, it has become an important resource of freshwater shrimps in China and is widely distributed in the middle and lower reaches of the Yangtze River in China. Crayfish are good at "taking things as they are", and rivers, lakes, reservoirs, rice fields and ponds can all be the shelter of crayfish. When the water temperature rises in spring, crayfish often move in shallow water. When it is hot in midsummer, it lurks in deep water. In winter, crayfish spend time in caves to prevent other animals from attacking. Crayfish not only has strong feeding ability, but also has the habit of gluttony and competition for food. In the case of high reproductive density or hunger, crayfish will have a "tragedy" of killing each other, and the newly shelled crayfish and young shrimp often become the "plate food" of "strong" lobsters. Crayfish have strong feeding ability and reproductive ability, and have low requirements for growth environment. Crayfish is an omnivore, which mainly eats animals. Small fish, shrimp, plankton, benthos and algae can all be used as its food. 6. Who knows the origin and history of Xuyi lobster? Thank you.

Xuyi lobster is a freshwater lobster, also known as crayfish, and its scientific name is Procambarus clarkii.

[Edit this paragraph] Origin and output

Originated in the United States, it spread to Nanjing in China in the 192s and 193s, then entered Douhu and Hongze Lake in Xuyi, and then entered rivers and lakes such as Tian Quan Lake, Maoer Lake, Swan Lake and Baxian Lake, where it grew, bred and expanded, becoming a beautiful landscape in Xuyi. Xuyi lobster is famous for its five lakes, namely Douhu Lake, Tian Quan Lake, Maoer Lake, Swan Lake and Baxian Lake. It is the peak season from May to September every year, with an annual output of 5, tons.

[Edit this paragraph] The most famous shisanxiang

Xuyi lobster has a unique taste, which is spicy, spicy, fresh and fragrant. As a popular and civilian food, it has an endless aftertaste and can't be tired of eating, so it has a strong market share and is favored by the majority of diners.

Xuyi lobster is famous for its cooking methods. Firstly, its ingredients are unique, that is, thirteen spices (composed of dozens of Chinese herbal medicines). In addition, large and small restaurants in Xuyi use washbasins and washbasins instead of bowls and plates when serving lobsters. Due to the high price of crabs in previous years, ordinary people had to use shrimp instead of crabs, so Xuyi lobster was dubbed as "crab assistant".

the most famous and influential lobster in Xuyi is 13 sweet lobster.

what's the secret? Looking at a red pot of shrimp, it is steaming, fragrant and appetizing. When eating, hemp, spicy, fresh, beautiful, fragrant, sweet, tender, crisp, fat and bright make people want to stop. After eating, the aftertaste is endless, and people can't forget it after winding their hands for three days.

It can be said that Xuyi was one of the earliest places to eat lobster. With the popularity of 13 sweet lobster, in order to promote the economic development of Xuyi, the people of Xuyi held the first loong Xuyi Lobster Festival in mid-July 2. During this period, many activities were held, such as "Large-scale Literary Evening", "Tian Quan Lake Dragon Boat Race", "Mountain Off-road Vehicle Exhibition Race", "Water Traditional Folk Wedding" and "Lobster Banquet for Thousand People".

[Edit this paragraph] Habits

Xuyi, also known as "Crayfish", belongs to the same family of crayfish, and often lives in the field and its shore.

crayfish, which is large, has a thick shell and a dark red body. It originated in North America, was introduced by Japan, and was introduced to China in 193s. Because of its strong ability of survival and reproduction, crayfish can be seen in southern China, especially in various provinces and cities in the Yangtze River basin. The harm that crayfish can do to dams is determined by its habit of burrowing. Its front end has a pair of pincers-like claws, which make holes quickly and widely. Because of it