Preliminary observations on the hydrography and inshore plankton in the Bay of Bengal off Visakhapatnam coast

Plankton investigation in Indian waters is in its infancy and most of the observations so far made are confined to a narrow coastal belt of water not exceeding two to five miles width, the samples being collected by towing a net from country crafts like the catamaran. Sewell (1913) gave the earliest account of the plankton from the south-east zone of the Bay of Bengal, based on a large number of samples collected from R.I.M.S.S. " INVESTIGATOR " during the survey season 1910-12. He found that while in the northerly region of the zone under survey the plankton exhibited a regular banded arrangement, there was uniform distribution of the plankton in the southerly region. Other studies have so far been largely confined to the inshore waters. Menon (1931), Aiyar et al. (1936), and Rama Murthy (1953) studied the qualitative and quantitative aspects of the plankton off the coast of Madras City. Chacko (1950), Prasad et ah (1952) and Prasad (1954) have made preliminary investigations on the seasonal variations and distribution of the plankton in the Gulf of Mannar. Ganapati and Murthy (1953) made a preliminary survey of the quantitative variations of the phytoplankton at various depths and distances in the neritic waters off Visakhapatnam. In addition to these general investigations accounts of special groups of planktonic organisms from the Bay of Bengal are also available