Observations on feeding behaviour and survival rates in the estuarine calanoid copepods <i>Acartia spinicauda </i>and <i>Heliodiaptomus cinctus</i> <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">(Crustacea: Copepoda: Calanoida)</span>

Abstract

Experiments were conducted on the calanoid copepods, <i>Acartia spinicauda </i>(Acartiidae) and <i>Heliodiaptomus cinctus </i>(Diaptomidae) in order to determine food preference and survival rates respectively. Adults of <i>A. spinicauda </i>were fed<i> </i>monocultures of <i>Tetraselmis gracilis </i>(Chlorophyta) and <i>Skeletonema costatum </i>(Bacillariophyta), whereas, adults <i>of H. cinctus </i>were fed on five different combinations of phytoplankton feed . Total hourly differences in pigment<i> </i>concentrations indicate that <i>A. spinicauda </i>preferred to feed <i>on T. gracilis </i>(90.08%) as compared to <i>S: costatum </i>(55.87%). A<i> </i>combined feed of <i>Isochrysis galbana </i>(50%) and <i>Chaetoceros </i>sp. (50%) was found to be most satisfactory in case of <i>H. cinctus </i>as there was no mortality till the 8^th day and only 57% mortality on the 14^th day. However, total mortality occurred<i> </i>on the 15^th day. The results indicate that feeds played an important role in determining the survival rates in <i>H. cinctus.</i>