A study of Hector's dolphins has found they are more threatened by gill nets than previously thought.
Fishermen are allowed to set vertical panels of netting in Akaroa harbour near Christchurch between April and August because it was thought that dolphins stayed out of the inner harbour in winter.
Researchers from the University of Otago set up underwater microphones in the harbour to check whether that was true and discovered that the dolphins are actually present for much of the season.
Accordingly, they said the ban on gill nets should be extended. The research has been published in the Endangered Species Research journal.