A New Zealand and Australian research team says it has confirmed it is possible to study whales without killing the mammals.
The Antarctic Whale Expedition has arrived in Wellington after six weeks aboard the National Institute of Water and Atmospheric Research's vessel Tangaroa.
Dr Nick Gales from the Australian Antarctic Division says countries need to collaborate to conserve marine mammals rather than killing them.
He says the voyage is part of a larger programme with the International Whaling Commission to change the way countries work together in conserving marine mammals in the Southern Ocean.
Japan has just wrapped up its controversial whaling season, in which whales were killed for scientific research.