清代臺灣史研究長期以來偏重陸地的農墾活動、行政統治和族群關係，相對忽略在綿長的沿海與廣大內海水域從事漁、鹽業活動的人群及其歷史。創立於荷蘭東印度公司統治時代，後經一定程度的改造與轉換，而持續被明鄭及清朝繼承的「贌港制度」，就是一個明顯案例。本文以位處臺江內海東北側、在明鄭及清代繳納港餉的「新港並目加溜灣港」為個案，具體分析「港戶」的水域權利，在清朝統治政策、社會發展以及自然環境變化交互影響下的演變發展。 本文將具體說明，清政府在統治初期，將荷蘭東印度公司每年依競標制度出的漁場定額化，導致當時承攬港餉者得以「港戶」之名，長期控制水域。但因清朝官府改革稅收政策的著眼點，僅在於稅額的定額化，而不是制定一套完整的水域經營管理制度，因此港戶究竟擁有怎樣的水域權利，並沒有在港餉定額化的同時清楚劃定，而是在後來一再面臨官府的治理政策、整體社會經濟發展以及自然環境變動等因素，不斷地調整而釐清，才逐步確立。

For quite a long time, researches conducted on Taiwan under the Qing Empire have been focused on agricultural settlement, administration, or ethnic relations. These researches have tended to overlook the history of the fishermen, fish sellers and salt dealers who operated on the coast and around lagoons. Consequently, the tax farming system related to the coves of Taiwan, the Pugang System (贌港制度), which was established by The Dutch East India Company and inherited by the Zheng and Qing rulers, has been overlooked by most historians. The present article focused on two coves, Xingang (新港) and Mujialiuwangang (目加溜灣港 ), in southwestern Taiwan in order to investigate and understand the monopoly merchants’ dominance over the waterways with the support of the Pugang System. It reveals that the merchants’ degree of dominance was constantly influenced by policies, social developments, and transformations of the natural environment. This present article proceeds to argue that the Qing court’s adjustment of the Pugang System laid the ground for the monopoly merchants’ lasting dominance over the waterways. The Dutch had established the system of taxing farming, thus selling monopolies over the waterways to the highest bidders. Subsequently, the Qing set fixed prices on this kind of tax farming, so the monopoly merchants gained permanent control over the waterways. However, the merchants’ dominance over the waterways was not explicitly ensured by the taxation laws. Their dominance was also constantly affected by government policies, social and economic developments as well as by natural changes before final consolidation.