Limnological Reconnaissance of Southern Sakhalin

II. Zooplankton

Abstract

The zooplankton of six lakes in the southern part of the Island of Sakhalin is discussed. The percentage composition of the zooplankton is given in Table 1, from which will be seen the general zooplankton-type of each lake in early summer. The dominant species which at this season make up more than 50 per cent. of the whole zooplankton are two rotifers, Asplanchna and Keratella. The distribution of the species observed is given in Table 3. Except Holopedium gibberum and Tachidius littoralis, no boreal elements at all were found in the planktic fauna of these lakes.