LIFE-CYCLE OF CALANUS-CHILENSIS BRODSKY IN BAY OF SAN-JORGE, ANTOFAGASTA, CHILE

The copepod Calanus chilensis is an endemic component of the zooplankt on community in northern Chile. Size distributions of adult females, r elative frequency of copepodid stages and relative numbers of adult ma les and nauplii, suggest the presence of at least 6 generations during the year, although the species seems to continuously reproduce throug h all seasons. Temperature profiles from 0 to 175 m indicated the pres ence of the 'El Nino' current during March and April. Surface temperat ure ranged between 21.1 and 13.1-degrees-C. Warm waters during the 'El Nino' event seemed to affect the body size of adult females and the n ormal course of cohort development, although the population tended to recover rapidly through the subsequent months. We discuss the role of oceanographic conditions in controlling the life cycle of this species , as well as continuous growth through the year compared to other Cala nus species.