Since the Taijiang Inland Sea region had unfavorable conditions for agriculture, local residents constructed fish farms in the lagoons and wetlands. The Qing Dynasty continued the taxation system developed by the Dutch to manage the economic activities that took place in the inland sea, with taxes on fish farms, fishing nets and fishing boats. As early as 1640, salt fields had already been developed in Laikou, by the Taijiang Inland Sea. In 1665, (year 19 of the Yongli regime and year 4 of the Kangxi regime), Chen Yonghua of the Ming Zheng regime introduced the technique of evaporating seawater to produce salt, which in turn started the development of the salt industry in south Taiwan. Constructed along the shores of Taijiang Inland Sea, “Laikou salt field” is the earliest documented salt field in Taiwan. In the “Reconstruction and Repair of Buildings in Taiwan Prefecture” from the Qianlong period in the Qing Dynasty, there are details about the process of salt making and the spatial layout of the Zhounan production site, and the record also mentions that there were already six salt production sites in Taiwanfu, including Zhounan, Zhoubei, Laibei, Lainan, Laixi, and Laidong.