Salinity, pH and Species Diversity of Ichthyoplankton in Hooghly Estuary, West Bengal, India

Investigation on some limnological factors like salinity and pH as well as species diversity of ichthyoplankton at three different sampling stations, viz., Light house (Station-1), Kachuberia (Station-2) and Haldia (Station-3) in the Hooghly estuarine complex of West Bengal was carried out. Samples of ichthyoplankton and water were collected every month during 2008. Station-1 recorded higher values of salinity, pH and species diversity compared to those of Station-2 and Station-3. The salinity and pH played an important role for survival of ichthyoplankton in the estuarine environment. Species diversity of ichthyoplankton also varied among the sampling stations. In all the stations maximum number of ichthyoplankton was available during pre-monsson (March to June) and minimum during monsoon (July to October). The species diversity gradually declined from the mouth towards the upper stretches of the estuary with the decrease in the salinity and pH of water.