Published online by Cambridge University Press: 05 December 2011
Important qualitative changes that have occurred in the zooplankton of Loch Leven within the present century are described, together with the methods and results of routine quantitative sampling during 1969 and 1972. In 1969, the crustacean zooplankton was a virtual monoculture of the carnivorous cyclopoid copepod Cyclops strenuus abyssorum and showed a marked absence of filter-feeders. This contrasts drastically with the situation in 1972 when the filter-feeding cladoceran Daphnia hyalina var. lacustris co-dominated with Cyclops. The standing crop data for the 2 years are compared and the important rotifers mentioned.