Abstract

The Tamshui River is the largest river in northern Taiwan. It opens by a small mouth at Tamshui into the Taiwan Strait and pours wastes from sewage, industry and the street water of Taipei City, along with the sandy waters from upper mountainous areas into the sea. Salt water during high tide reaches the edge of Taipei City. At this time, marine plankton is easily mixed with the freshwater biome. In order to know which algal species have invaded into the estuary region of the Tamshui River, the author made a short cruise from Kuantu to Shetzu on the afternoon of July 18th, 1965 around 3:00 P. M. at the time when the tide from the sea was rising. In this collection, a small plankton-net was towed by a small vane-boat horizontally just beneath the surface, at that time a breeze was coming in from the sea. The small boat moved very slowly in the same direction that the tide was entering but in the opposite to the freshwater coming from the mountains, therefore, the collection contained plenty of both marine and freshwater algae. The zooplankton has being studied in a series of projects carried out by the Institute of Fishery Biology of the Ministry of Economic Affairs (Liaw 1965, and Tan 1967), but the algal plankton has not been carefully studied, so the author has undertaken a detailed study of the samples collected.