During summer, upstream migrations of juvenile freshwater eels (elvers) of both species(Anguflla australis schmidtiiPhillipps, the short‐finned eel, andA. dieffenbachiiGray, the long‐finned eel) are observed at hydro‐electric dams and waterfalls. The migration was sampled at Karapiro Dam on the Waikato River, 1970, 1971, and 1974, and samples from a further 11 areas throughout the country were analysed.