abstract
Zooplankton was obtained from 186 freshwater bodies sampled on Marion and Prince Edward Islands during the summer of 1974. For comparative purposes the lentic water types of the islands were classified into six categories, namely crater lakes, tarns, scarp lakelets, glacial lakes. Post-glacial lakelets and elephant seal wallows. The main physico-chemical and morphological characteristics of each group are briefly outlined. Apart from a few insects, oribatids and oligochaetes, the freshwater fauna consisted of Entomostraca, notably the calanoid copepod Pseudoboeckella volucris. Zooplankton abundance and species diversity are significantly correlated with the trophic status of freshwater bodies which, in turn, is a function of height above sea-level or distance from the sea. With the change from eutrophic to aligotrophic water bodies, P. volucris increasingly dominated the Zooplankton while its sex ratio, with obvious implications on productivity, became more strongly skewed in favour of females. Previous reports on seasonality and habitat preferences of Pleuroxus aduncus, Marionobiotus jeanneli and Tigriopus angulatus are briefly elaborated on.
