Reproduction of common frog species (Bufo bufo and Rana temporaria) in commercially managed fishponds can be threa - tened due to destruction of egg clutches or early developmental stages of tadpoles. The phenomenon is described based on a monitoring of a forest fishpond in the south-eastern part of Central Bohemia. Data on the size and growth of egg clutches and tadpoles in relation to time and weather conditions are also described and Ivan Vergner.