DISTRIBUTION AND SUMMER DIAPAUSE OF CANTHOCAMPTUS-STAPHYLINUS (JURINE) (COPEPODA, HARPACTICOIDA) IN LAKE-LADOGA

The spatial distribution of Canthocamptus staphylinus (Jurine) in Lake Ladoga was examined. C. staphylinus is one of the most numerous speci es of harpacticoids in the lake. It can dwell in almost all littoral b iotopes. In profundal biotopes strongly exposed to anthropogenic influ ence (pollution and eutrophication) only this species of harpacticoid was found. A peculiarity of C. staphylinus biology is that in summer i ndividuals are in the resting stage as cysts. In summer active individ uals were found in littoral habitats at a water temperature of 20 degr ees C, but their number was small in comparison with cold periods of t he year. In the littoral zone the relative number of individuals in cy sts was clearly related to water temperature. Twelve degrees temperatu re appears to be critical for development of littoral populations of C . staphylinus.