The biology of Leydigia acanthocercoides has been studied under laboratory conditions with reference to longevity, instar duration, growth, fecundity and embryonic development at a temperature range of 28-30 'C . It has three preadult and thirteen adult instars . Under the given laboratory conditions this species produces 20 eggs during a life span of 23 days . The number of eggs produced is uniformly constant in all adult instars . The growth rate seems to be exponential in the early phase of the life cycle as in other Cladocera . The general pattern of embryonic development of L . acanthocercoides is similar to those of other tropical cladocerans though differences in the duration of total developmental period have been recorded .

The embryonic and post embryonic development of the cladoceran Daphnia carinata has been studied in the laboratory at two different temperatures (35 and 15°C). The duration of embryonic development is inversely proportional to the temperature. The total number of instars increases with the decrease in temperature ; nine at 35°C and sixteen at 15°C. The average duration of an instar is 29 hrs at 35°C and 128 hrs at i3°C . The lower (15°C) and the higher (35'C) temperatures restrict egg production .

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The various physico-chemical factors such as rainfall, depth, water spread, temperature, dissolved oxygen, pH, redox potential, alkalinity, total phosphorus, nitrate, kjeldahl nitrogen and dissolved organic matter were studied both diurnally and seasonally and depth-wise for the period from April 1977 to March 1978 . Consideration of physico-chemical factors indicates that they are inter-related . The main characteristics of Sathiar clearly indicate that it is highly eutrophic .