Introduction to oyster reefs: Oyster reefs are formed north of the Haihe River in the Tianjin Coastal Plain, in the lower reaches of the Chaobai River and Jiyun River in Ninghe County and Baodi County. They are concentrated in the southern part of Baodi, the middle and eastern areas of Ninghe River, and the most typical areas are The core area of ​​oyster reefs in Toukou Village, Ninghe County. The oyster reef is composed of long oysters and near river oysters, with clear accumulation layers in the profile, and the thickest one can reach 5 meters, which is rare in the coastal plains on the edges of the Western Pacific. The scale of Tianjin's oyster reefs is only comparable to that of the Pathumtani area north of Bangkok, Thailand, and the oyster reefs of Atchafalaya Bay and Point Au Fex Island in Louisiana, the United States. However, so far, no other oyster reef accumulation layer similar to the 5-meter-thick one in Tianjin has been found.