Abstract: Factors influencing the digestive enzyme activity of copepods are as follows:(1) Food conditions:Both seasonal changes in food supply in natural sea area and changes of prey species and diet concentrations during experimental feeding affect the digestive enzyme activity of copepods. Their relationship fits the"Assimilation Law",( 2 )There exists a positive relationship between digestive enzyme activity of copepods and their energy requirements at various growth stages.(3) Diurnal vertical migration of animals may influence their diurnal periodicity of digestive enzyme activity.(4)Copepod's"internal clock",which resembles the neuroendocrine system of higher crustaceans,may control its digestive enzyme activity,(5)Other factors such as physical and chemical factors(e.g.temperature,pH,lisht,etc.),time factors etc.

Key words: Babylonia areolata, cadmium exposure, bioaccumulation, metallothionein, DNAintegrity.