Oysters have lived on Earth for 200 million years and are the "milk of the sea" that nourishes humanity.

Summer is here, oysters are bubbling on the grill, and the city's fast-paced life slows down. Oysters, scientifically known as oysters, are the best shellfish that have lived on Earth for 200 million years. Tens of thousands of years ago, the ancestors of modern humans migrated all the way along the coastline, and it was the oysters known as the "milk in the sea" that replenished their physical strength and conquered the world.

Once used by civilians to fill their stomachs, oysters have since plummeted due to overfishing and environmental pollution, making them a mysterious food of the sea sought after by high-end restaurants. Today, with the gradual maturity of artificial culture, oysters are almost all over the coastal areas of the world, becoming the world's largest farmed shellfish.

1 Food supplies along the coastline

Human consumption of shellfish may have been 1 million years old, and prehistoric shell mounds piled up on mussel shells, including oysters, have been left on the earth's coastlines. The oldest shell mounds, from the African Mesolithic Period, 165,000 years ago, are located in the pinnacle region of today's Western Cape, South Africa, where shellfish on the beach and rock walls lie still after low tide, as if setting a table for human ancestors. Humans can easily obtain shellfish, and with the simplest stone tools, they can smash open the shell and enjoy the delicious juice and smooth and tender flesh.

72,000 years ago, some of the ancestors of modern humans embarked on a journey out of Africa. Trekking north from the Red Sea and along the Arabian Sea into India, their descendants continued to migrate for the next tens of thousands of years until they occupied the globe. The first human ancestors to leave Africa did not have dry food, but it is quite possible that they were sure where their food depots were – as long as they migrated along the coastline, mussels, including oysters, were the most nutritious food. Oysters feed on the filtration of micro-seaweeds and microorganisms in the ocean, making them home to rocks in the intertidal and subtidal zones. From the Indian coast to Australia, from the East Asian coast to the Western Hemisphere, from the Pacific Rim to Siberia, oyster populations are everywhere. Before learning to produce agriculturally, oysters provided energy for human migration along the coasts of the globe. Remains of human activity and eaten mussel remains are often seen on ancient migration routes. Archaeologists have found that many hunting civilizations exist on the coast and bay, and as long as a bunch of oyster shells are found, it means that there is a primitive gathering place or ancient village not far away from ancient humans.

Most importantly, oysters, known as the "milk of the sea", are not only life-saving food given by the sea, but also high-grade nutrients that promote brain development. Oyster meat contains up to 50% protein and is rich in amino acids, glycogen and vitamins, especially omega-3 fatty acids unique to seafood, which are essential for brain development. So in a way, oysters not only helped our ancestors go further geographically, but also helped them go far intellectually than other species.

2 Europeans like to eat "raw" Chinese love to eat "cooked"

Both the East and the West praise oysters as a food. In the Shennong Materia Medica, oysters are listed as the best products, and it is recorded that "oysters, salty and flat taste, the main typhoid fever and fever, warm malaria sprinkled ... Long service, strong bone joints, killing evil qi, prolonging years. In Shakespeare's dramatic lines, "oysters" represent all the good things: "I can use the sword to get the best oysters in the world at will." ”

The types of oysters in different seas are different, and the taste of oysters tasting in the East and the West is also different. Chinese like to cook oysters over a fire before eating them. During the Tang Dynasty, the south began to eat fried oysters - Liu Ke's "Records of the Ridge Table" recorded that according to the size of the oysters, the eating method was different: "The oyster meat is large and pickled; the small one is fried." "In the Song Dynasty's "Tokyo Dream Record", in addition to stir-fried chicken, fried rabbit, fried sheep, fried loin, and fried oysters. Su Shi was demoted to Huizhou, and his friends entertained him with oysters, and there was a text: "The sea is a man who sacrifices oysters, dissects them, gets several liters, boils meat and pulp and wine together, eats very beautifully, and has not begun to have it". Even Hong Qigong in the literary work "The Legend of the Archery Hero" "even ate the Mandarin Duck Five Treasures Four Times" in the imperial kitchen, and he never forgot: "Lychee white loin, quail soup, sheep tongue stick, ginger vinegar snail, oyster stuffed lamb tripe..."

Europeans prefer to eat oysters raw, striving for the original smooth beauty of oyster meat, mixed with delicate salty, that is, the impact of the "copper flavor" or "ore taste" from the ocean. The most common European and American oysters are eaten with open shells, dipped in lemon juice and eaten empty. Hemingway has a similar description in "A Flowing Feast": "When I eat oysters with a strong seafood smell, the cold liquor dilutes the slight metallic taste of oysters, leaving only seafood and juicy tender meat." I sucked in the cold juice from the oyster shell, and then I rushed down to my stomach with the help of the wine, and the feeling of emptiness disappeared, and I was happy again. ”

In Europe until the Victorian era, oysters used to be the food of the poor. The character Sam Weller of the English writer Dickens's first novel, Pickwick 's Tale ( 1837 ) , states this way : " Poverty and oysters always seem to go hand in hand ... The poorer a place is, the greater the demand for oysters... On average, every six houses you can see an oyster stall, lining the streets. Sometimes a man I know has a decent life, but I can see him rush out of the house and eat his oysters in extreme despair. The British writer Maugham wrote at the end of The Moon and Sixpence: "He has always been obsessed with the days of the past, when thirteen large oysters could be bought for only one shilling." ”

Every time the tide rises is a gift from the ocean – oysters, once so common, have nothing to do with luxury. What exactly changed the identity of oysters and made them a fashionable luxury food on both sides of the Atlantic, associated with lavish banquets and exquisite tableware?

In The Devil's Supper: Peppers and Chili Culture That Changed the World, the reason for the oysters' transition from food for the poor to the tip of the tongue of the rich is that "when a large number of workers poured into industrial cities, they first ate most of the oysters, and then the rivers polluted with industrial wastewater wiped out another part of the oysters." Oysters began to become a rarity from being readily available, and to get them had to be found in the pristine ocean far from the city. ”

The main reasons for the drastic decline in oyster resources in nature are overfishing and water pollution. The former is like the oyster beach off the coast of Venezuela, where there are few oysters left after tens of billions of fishing in just 30 years in the early 16th century. Even with subsequent government efforts to limit fishing, rehabilitate habitats, help oysters spawn, and so on, there is little chance of a rebound in local oyster populations. Seawater pollution is responsible for the sharp decline in oyster populations. Contaminated seawater means that the oyster habitat has been severely damaged. Although oysters can lay millions of eggs at a time, most of them are washed away by the sea to become fish food, and only the lucky few who find the reef and cling to it can survive. Habitat destruction means a sharp decline in wild oyster populations. According to the Nature Conservancy, 85 percent of the world's oyster reefs have disappeared, leading people to look deeper deeper into the ocean for shellfish reefs – "the most dangerous marine habitat on earth", which casts a veil of mystery over wild oysters.

So from the end of the 19th century, eating oysters symbolized a rich life. In his work "My Uncle Hule", the French writer Maupassant described the aristocratic life that Joseph's father longed for, because he saw the noblewoman eating oysters and dreamed of buying some for his family: "The father suddenly saw two gentlemen asking two beautifully dressed wives to eat oysters. An elderly sailor in rags took a knife and pried open the oysters and handed them to the two gentlemen, who in turn handed them to the two wives. They ate the oysters in a small handkerchief with a small handkerchief and their heads slightly forward so as not to stain their robes; then with a quick slight movement of their mouths, they sucked in the juice and threw the oyster shell into the sea. "The value of oysters has risen again and again, except for standing and eating as described in the novel, more often than not, oysters have entered high-end restaurants. The latter took great pains to create elegant, high-profile menus and recipes tailored to this food, represented by the Rockefeller oyster dish created at Antoine Antoine's Restaurant in New Orleans in 1899. Rockefeller oysters are coated with green fennel and vanilla butter, paired with shiny porcelain and silver tableware such as oyster forks, and details suggest their value.

3 China's artificially farmed oysters are the first in the world

Plump oyster meat is a gift from the ocean. The oyster's way of survival is to fix itself on the rocks of the intertidal and subtidal zones, controlling the opening and closing of the two thick shells by means of a strong muscle in the middle, and the mantle and other organs are distributed around the muscle column. If you want to farm oysters in captivity, you have to provide suitable fixing house for oyster seedlings. China was the world's first country to cultivate oysters, and as early as the Han Dynasty more than 2,000 years ago, residents along the southern coast of China mastered the technology of planting bamboo to raise oysters. By the Song Dynasty, the "cultivating the sea" technology was further developed, and there was already a large-scale "oyster field"; Zheng Hongtu of the Ming Dynasty recorded in detail the bamboo cultivation method in Fujian.

Many people may still have an impression of oysters on the misunderstanding of expensive imports from Australia and France and the special offers of the Rich Club table. In fact, in China, which has a long coastline and rich aquatic resources, eating oysters has long been a daily consumption of good quality and low price, and the quality of oysters in many parts of the country is no less than that of imported goods. From 2000 to 2018, China's oyster production increased from 3.292 million tons at the beginning of the period to 5.1398 million tons at the end of the period, as early as 2017, China's artificially farmed oyster production has accounted for more than 80% of the world's total aquaculture production. Therefore, a visit to the Southern Farmers' Market Seafood Market will find that local residents eat oysters can be regarded as a common meal.

Where does the taste of oysters come from? Simply put, shellfish's rich and delicious taste comes from the flavor substances that accumulate in its body to reserve energy and balance external salinity. Shellfish use amino acids to fight seawater salts and balance osmotic pressure, so the higher the saltiness of seawater, the more delicious the shellfish. Therefore, the taste of oysters grown in different seas, at different temperatures and in different microbial environments is also different, but in general, the biggest impact is the salinity of seawater – to some extent, the taste of oysters is the taste of the seas in which they are grown.

China's oysters have a variety of flavors, and there are diverse oyster populations distributed in coastal areas. "Pacific oysters" is the main cultured species in the northern coast of China, commonly known as "sea oysters", the production area is distributed in the north from the Yalu River estuary, south to the surrounding seas of Lianyungang, Jiangsu, the output reached 1.2411 million tons in 2018, accounting for 24.15% of the total output of oysters in the country that year. Portuguese oysters (commonly known as "oysters") are the main cultured species in Fujian and Zhejiang, mainly distributed in the shallow waters of the intertidal and subtidal zones of Zhejiang, Fujian and eastern Guangdong in the East China Sea. Portuguese oysters are also the most productive oysters, with Fujian oyster production increasing to 2,117,200 tons in 2018, accounting for 41.20% of the country's total oyster production. Hong Kong oysters, commonly known as "white meat" and "big oysters" by southern coastal residents, are mainly distributed in Guangdong, Guangxi and Hainan in the South China Sea. Oysters, known as "oyster locusts" in coastal cities in northern Zhejiang, belong to the Omi oysters and have historically been widely distributed in the waters of China's coastal estuaries. Because of the dark brown color of the soft body of the Omi oyster, fishermen along the southern coast of China also commonly call it "red meat".

Oyster farming not only provides aquatic seafood, but also has environmental benefits. Beneath the double shell, the main body of the oyster consists of a soft sheath membrane and gills that filter food. Based on the feeding habit of using gills to divert water flow to filter nutrients and algae, oysters are born with water purification functions. On the Coast of Connecticut in the United States and in the heavily polluted waterways of New York, oyster farms have been tried to purify water and provide local food. And when a large number of oysters appear in a certain place, in turn, the "oyster reef" or riverbed can create habitat for other marine life, and sea anemones, other mussels, small fish and shrimp, and larger fish will settle in succession. Oyster farms are also protected against some harsh climate changes, such as coastal flooding caused by major storms. Oyster reefs can mitigate the impact of disasters by absorbing 80% or more of wave energy, and oyster farms are much more economical and practical than man-made partition solutions.

Eat in China

A map of Chinese cuisine with oysters

Summer is the season for barbecues, and how can a perfect barbecue be made without grilled oysters? As a natural eating vessel, oyster shells hold juicy oyster meat and golden garlic grains, which resonate on the tongue of fire. In addition to roasting, oysters also have steaming, salt baking, raw frying, soft frying, raw sunning, filling and other ways to eat, whether it is called oysters, oysters, oysters, oysters or oysters, oysters have their own cooking methods everywhere.

In the coastal cities of Liaoning and Shandong, a special snack called fried oyster locust is popular, which is simple but delicious. The sea oysters, which have been slightly marinated in cooking wine, wrapped in egg mixture and sticky starch, are directly cooked and fried until golden and crispy, and the outside is charred and tender. Another specialty snack, radish silk sea oyster buns, is to crush the sea oyster meat and pork together, add the boiled water after the radish shredded filling, wrapped in the dough basket drawer steaming, more delicious than the usual meat buns.

The south likes to use the smooth tenderness of eggs to match the deliciousness of oysters. In addition to the simplest home-cooked oyster steamed custard, oyster frying in southern Fujian is first mixed with tapioca flour and eggs into a moist dough cake, then fried in a pan until golden brown on both sides, then covered with fresh vegetables and drizzled with some sweet and spicy sauce. With a crispy crust and juicy oyster meat on the inside, it is a very popular snack. Similar versions include oyster sauce in the Chaoshan region, which is seasoned with green onions, ginger and rice wine, kneaded into batter and spread into oyster cakes; or Taiwanese snack oysters, also known as oyster fried and oysters, which are made of flour, oyster meat, minced pork, minced leeks, minced cabbage, chopped celery, allspice powder and a little pepper, and then fried in oil.

In addition to these regional snacks, there are also dishes about oysters fried oysters, pan-fried golden oysters, lotus oyster sauce, ham stewed oyster sauce, fresh oyster tofu... Along the coastline, you can eat a map of oysters' delicacies.

Locally sourced materials

The wisdom of China is the "oyster" house

After enjoying the delicious oysters, what should I do with the oyster shells? The ancients of our country had a new idea for where the oyster shell went - since the double shell of the oyster can provide solid shelter for its soft body, why not build a wall to shelter from the wind and rain, and build a "oyster" house for yourself?

If the tang Dynasty Liu Ke's "Records of the Ling Table" is not false, the practice of building walls with oyster shells in China existed as early as the Eastern Jin Dynasty: "Lu Ting, Lu Xun turned his back on Guangzhou, and after being defeated, the Yu Party ran into the island to live in the wilderness, but ate oysters, and the shell was a wall." However, most of the existing oyster shell wall buildings were built in the Ming and Qing dynasties, as the Lingnan scholar Qu Dajun said in the book "Guangdong Xinyu": "Panyu Zitang Village has many oysters." There are mountains on the seashore, known as stone oysters, very tall, in ancient times oysters were born on it, hence the name. Now dig the ground to two or three feet, that is, to get oyster shells, many are inexhaustible, and the rate of living in the walls and houses is made of oyster shells, and it is a bright sight."

How are Oyster Walls built? What is it like to live in such an "oyster" house?

According to different sizes and varieties of materials, the traditional oyster wall construction process is also slightly different, but in general, it is like this: the base is laid with green brick wall feet; the outer wall is glued with oyster shells, erected laterally, and neatly discharged; and the inner wall is built with a mixture of raw soil and oyster shell ash. The oyster wall built in this way, the thickness of the wall is about 50 or 60 centimeters, and it has stood firm after more than 600 years of rain and wind, which can be said to be quite strong. The Guangdong Xinyu also confirms: "Oysters, knotted by saltwater, with their shells and walls, are as high as five or six inches." ”

The oyster shell wall is not only neatly arranged, but also the oyster shell is scaled and built in a downward 45 degrees. This does not accumulate rainwater, and large oyster shell shadows can be formed under the sun. Because of the special material of the concave and convex and dense holes on the surface of the oyster shell, it is heat insulation and is not afraid of insects, which is very suitable for the weather in Lingnan, and the oyster shell wall has been called "convex brick shading wall" by the locals.

Unfortunately, during the Qing Dynasty, the "ban on the sea for moving the border" was implemented, and the coastal provinces "did not allow any sails to enter the sea, and violators set up heavy codes"; during the Kangxi Dynasty, coastal residents were ordered to move fifty miles inland, resulting in the destruction of a large number of coastal buildings, including oyster shell houses. Today, there are only a few dozen ancient buildings with oyster shell walls in the Pearl River Delta region, and this special material of ancient buildings deserves people's attention and love.

(Original title: Oysters nourish the "milk in the sea" for human beings)

Source: Beijing Daily Author: Elis

Process Editor: L021

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