Abstract
Seasonal variation in specific amylase and trypsin (i.e. alkaline proteolytic enzymes) in copepodite stage V and adult male and female Calanus finmarchicus is presented. Adult females had their highest specific amylase and trypsin activity during the spawning period (April-May). Specific amylase and trypsin activities in adult females in this period were respectively 2 and 10 times greater than the levels found in copepodite stage V during the study period. Activity levels of both these enzyme groups in adult males were low when they were present in the population during February-April.
The specific amylase activity in copepodite stage V showed a diel variation pattern with maximum activity at night. The seasonal and diel variations in digestive enzymes in C. finmarchicus are discussed in relation to overwintering strategy and variation in abundance and chemical composition of the phytoplankton stock. It is suggested that both internal and external factors regulate the enzyme activity in copepodite stage V and VI C. finmarchicus.
