From the introduction:
"Estuaries form the nearest available biological habitats for the people, as most of the harbours and cities are situated on estuaries. Along the east coast of India several estuaries and lagoons like Ennore, Adayar, Cooum, Kovalam and Pulicat are found in and around Madras city of Tamil Nadu state. Here the Ennore estuary is taken up for detailed investigations.
The pioneering attempt of making qualitative study of the plankton of Ennore estuary was by Chacko and Rajagopal (1962). Then a few reports were published depicting the amplitude of seasonal changes of zooplankton of Ennore estuary (Evangeline and Subbiah, 1969., Srinivasan and Raghunathan 1977, 1978). Subsequently variation in relative proportions of specific groups such us chaetognaths (Srinivasan, 1976, 1978, 1980) and copepods (Raghunathan, 1980) were studied. The Gobioid fishes of this estuary were studied by Menon and Govindan(1976) and Menon and Rema Devi (1978). The pollution aspects of Ennore estuary were studied by Sreenivasan and Franklin (1975).
Despite the present knowledge of various zooplankton taxa accumulated through these reports, a complete picture on the different aspects of the zooplankton and hydrography of this estuary, especially after the dredging operations carried out by Ennore thermal station to keep the mouth of the estuary open throughout the year, is wanting. Hence this biological investigation extending over two years (1976-1978) was carried out with the view of studying the zooplankton and hydrography"