Cause of death is still a mystery for dolphins

Scientists have no idea what killed two maui's dolphins found near the south head of Manukau Harbour.

The dolphins were discovered in December and have been on ice at Massey University for the past few months awaiting examination.

An autopsy has been done but researchers are none the wiser.

A number of dolphins have died after being caught in set-nets over the years. Others have fallen victim to the lethal bacterial agent brucella. Both possibilities have been ruled out in the latest case.

The maui's dolphin is only found in New Zealand and there are about 100 in existence.
Set-netting is now banned around the Manukau Harbour mouth and along the west coast in an effort to protect the endangered species.

Scientists are also trying to find out more about brucella after finding traces of it in other dead dolphins.

"We do know that it causes abortions and reproductive failure in livestock and there is some evidence from international examples that this may be the case for dolphins," Department of Conservation spokeswoman Nicola Vallance says.

"It has been diagnosed in a variety of whale, dolphin and seal populations worldwide, but our understanding of the disease in these species is still very limited," she says.
Report dead dolphins to department staff, phone: 0800-362-468.