Observations on the hydrological conditions of the surface waters off Waltair (Bay of Bengal) during 1964-'66

Abstract

Hydrological studies at Waltair have been confined mainly to inshore areas up to 10 fathom line (18 metres), (Ganapati and Sarma 1958, Ganapati and Rao 1958, Rao and Rao 1962). Investigation beyond this region covered only part of the year (Ganapati et al. 1956, La Fond 1954, 1955). Variations of the surface salinity and the temperature of continental shelf waters and some stations beyond, were investigated from October 1952 to March 1953 by Ganapati and Murthy (1954). The upwelling and sinking phenomena were studied by La Fond (1954, '55), while Ganapati et al. (1956) observed the vertical chemical structure of water and the changes which occurred between October 1955 to May 1956. However, considerable work still remains to be done, especially with respect to the nutrient salts of the offshore region. The present paper deals with the observations made from April 1964 to December 1966 on surface temperature, salinity, dissolved oxygen, phosphate and silicate content of waters off Waltair up to the depth-line of 55 metres (30 fathom) and a distance of about 20 miles from shore.