Population dynamics of Simocephalus vetulus (O.F.Muller)

Investigations on the population of Simocephalus vetulus (O.F.Muller)were carried out both in natural and laboratory conditions,at different temperatures and food concentrations. The temperatureand food were found to have a pronounced bearing upon the rateof development and the life span of this zooplankter. The temperaturealso influenced the rate of growth and the size of populationby increasing the instantaneous rate of birth. Besides foodand temperature, the hydrogen ion concentration of the wateralso appeared to influence the size of the population. Therewas a positive correlation between fecundity and death ratewith a strong facultative relationship between fecundity andfood supply.