Oyster is a kind of marine shellfish that lives on coastal rocks. There are many kinds of them, about 20 of which are distributed along the coast of China. At present, the varieties that have been cultivated in China mainly include: oyster, oyster near the river, oyster long, oyster in the Pacific Ocean and oyster in Dalian Bay.

Oysters are easier to catch than fish. As early as the Neolithic Age, our ancestors began to eat wild oysters. Chinese archaeologists have found oyster shells from the remains of primitive humans, which is a good witness. Later, with the development of fishing technology and the continuous progress of human life, people cultivated oysters artificially on the beach just like keeping bees on land and raising fish in ponds. China is the earliest country to cultivate oysters in the world. According to records, China began to cultivate oysters with bamboo before the Han Dynasty, and it has a history of more than 2,000 years.

Oysters have two shells with various shapes, such as triangle and oval. Long and narrow and fan-shaped and so on. The color of shells is very similar to that of surrounding rocks, such as blue-gray, light yellow, gray-green and tan, with colorful stripes in the middle.

Oyster is a strange and interesting animal with many unique living habits. Newborn young oysters can swim freely in the water, but when they meet the right environment, they begin to parasitize on rocks or other hard objects in the sea and live a fixed life for life. Interestingly, once the young oyster is fixed, it becomes an animal that will never crawl like a nail into the wood. According to this peculiar living habit of oysters, people prepare all kinds of seedling pickers before the breeding season. Such as cement columns, big shells, rubber strips and the like. Neatly arranged on the beach, it will be used as a "bed" for thousands of oyster larvae in Qian Qian, so that they can "settle down" comfortably.

The two shells of an oyster have their own uses. A thick shell is always fixed on the rock and will not move at all; The other flat shell can be opened and closed freely up and down, swallowing all kinds of small creatures from seawater. The ocean is a huge "granary", and the tide is like a hard-working "cook", bringing rich food to oysters day and night. When the tide is high, the oyster is submerged by seawater, and it slightly opens its shell. The water flows into the mantle cavity from the abdominal edge of its mantle, then passes through the gills, and then flows out from the back edge.

Oysters rely on this water flow process to breathe and eat. When the tide receded, the oyster closed the shell and closed the door to sleep.