Dolphin's death under investigation

20:52, Sep 15 2013

A critically endangered Maui's dolphin has died of old age, Conservation Minister Nick Smith says.

The dolphin was found yesterday at Glinks Gully, 15km south of Dargaville, within the North Island West Coast Marine Mammal Sanctuary.

Smith ordered an investigation into the death and specialists at Massey University carried out an immediate post mortem.

Smith told Radio New Zealand it disclosed that it was a female that died of old age.

He said the location of the carcass suggested the dolphin died in Kaipara Harbour, where many of endangered Maui's live.

Maui's dolphins are a subspecies of Hector's dolphins, and the smallest subspecies of dolphin in the world. They can only be found on the West Coast of the North Island between Dargaville and New Plymouth.

The dolphins mature between the ages of 7 and 9 and produce one calf every two to four years.

Set net fishing is one of the major threats to the dolphins. From 1921 to 2008, there have been 41 recorded deaths of the mammals, with two of them dying as a result of net entanglement. Three others died from possible or probable entanglement.

University of Otago zoology department associate professor Liz Slooten said the death was devastating.

"When you have got 55 individuals above the age of one year, with roughly half of those being females and half of those being breeding females, you have only got 13 to 14 breeding females. If you lose one of those that could literally cause extinction."

Even if it was not a Maui's dolphin, it would be very worrying if the dolphin was found to have died of unnatural causes because that would mean there were threats to dolphins in the area.

If the South Island Hector's dolphins were breeding with the Maui's dolphins, and that could help to strengthen and bolster the population.

"We really need to protect the area between the North and South Island so that can occur," Slooten added.


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