Observations on feeding behaviour and survival rates in the estuarine calanoid copepods Acartia spinicauda and Heliodiaptomus cinctus (Crustacea: Copepoda: Calanoida)

Abstract

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