北塘镇位于蓟运河与永定新河入海前的交汇处,南距塘沽约30华里,是天津市第二海产渔业基地。六十年代以前,由于海河、蓟运河、潮白河和金钟河等主要河流终年有淡水下泄,从陆地上带来丰富的营养盐类随流入海,促进了浮游生物和底栖生物的大量繁殖,为多种鱼、虾、蟹类的索饵、繁殖和栖息创造了良好的环境条件。据调查,仅在河口附近海区进行繁殖的经济鱼类就有30多种,尤其以盛产“银鱼紫蟹”而驰名。多少年来,北塘人民一直在渤海湾从事渔业生产, Beitang Town is located at the confluence of Jiyun River and Yongding New River before entering the sea. It is about 30 Wuli miles away from Tanggu in the south and is the second marine fishery base in Tianjin. Before the 1960s, due to the release of freshwater from major rivers such as the Haihe River, the Jiyun River, the Chaobai River and the Admiralty River, the abundant nutrient salts on land brought along with the inflow of the sea and promoted the large-scale multiplication of plankton and benthic organisms. A variety of fish, shrimp, crab feeding, breeding and habitat to create a good environmental conditions. According to the survey, there are more than 30 kinds of economic fish that are only propagated in the sea area near the mouth of the estuary. They are especially famous for their richness in the production of “silver crabs and purple crabs.” For many years, Beitang people have been engaged in fishery production in the Bohai Bay,