The migration of adult freshwater eelsAnguilla australisandA. dieffenbachiiwas studied in 3 areas: Lake Ellesmere (Canterbury) (43°48′S, 172°31′E); Lake Onoke (Wairarapa) (41°23′S, 175°08′E); and the Makara Stream (Wellington) (41°13′S, 174°43′E). In Lake Ellesmere, migrating eels began congregating at the outlet area nearest the sea in January and continued until June. Eels arrived in a definite sequence: A.australismales, females;A. dieffenbachiimales, females. Commercial catches exhibited a lunar periodicity with largest catches occurring just after the last quarter and smallest catches during the full moon. No obvious environmental factors were associated with the migration except that the largest commercial catches were made at times of high lake level. If the lake is opened to the sea during migration, fishing for migrating eels ceases and they escape out to sea. In Lake Onoke, aggregation of migrating eels in shallow areas nearest the sea began in February and lasted until May or June. The order of arrival of eels was similar to that of Lake Ellesmere. Catches showed a lunar periodicity with smallest catches being made during the full moon. In the Makara Stream, the downstream migration extended from January to May, but the majority of eels each year were caught in 3 nights. No sequence existed in the movement of eels of each species or sex, but females ofA. dieffenbachiimigrated last. Dominant factors influencing the migration were increases in water level and flow associated with rainfall in the catchment. Catches exhibited a lunar periodicity with major movement during the last half of the lunar cycle and maximum activity just before the last quarter.