Autopsy begins on rare hourglass dolphin that washed up on Southland beach, before being returned to iwi

The opportunity to autopsy an incredibly rare hourglass dolphin is being recognised as a "rare privilege" by an Auckland marine expert, before it's returned to iwi.

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Researchers at Auckland's Massey University are studying the rare marine mammal. Source: 1 NEWS

After the hourglass dolphin washed up in Southland in August, it was brought to Auckland for a post-mortem, which got underway this week.

"We've got a privilege, a rare privilege, to get an insight to the biology and to the life history of a species which is rarely ever been examined globally," Massey University's Dr Karen Stockin told 1 NEWS.

The hourglass dolphin, with its streamlined body and striking black-and-white colouring, normally lives in deep Southern Ocean waters, in the sub-Antarctic.

It's believed to have died less than a day before it was discovered on a Southland beach.

Stockin says it's only the third in the last 150 years to wash up in New Zealand, especially in a relatively pristine condition.

"There's really only a handful of them worldwide that have actually had the opportunity to be explored and examined," she says.

Dr Karen Stockin (left) and Ramari Stewart (right) study the hourglass dolphin. Source: 1 NEWS

It means Massey University's research will have worldwide impact for others studying marine mammals. 

The post-mortem begins with extensive measurements, before samples are taken.

Studying the body, Stockin says there's a lot you can learn. She points out the teeth, worn away in the front but still standing at the back.

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"Usually when we see animals that have got such wear and tear at the front, it would suggest they're very old animals," she says.

However that's at odds with the CT undertaken before the dolphin arrived in Auckland, which seems to indicate it could be a young adult or still maturing.

The hourglass dolphin's front teeth have been worn down, while its rear teeth remain in tact. Source: 1 NEWS

Another potential cause of the worn teeth would be the types of prey it's eaten - something there isn't much information about.

"That's one of the reasons why examination of the stomach contents will give us a better understanding of what the prey items are for these animals, and give us an indication if that will explain why there's more wear and tear on the teeth."

As well as helping researchers understand the hourglass dolphin species overall, Stockin says the post-mortem will help them learn more about how their environment is coping.

"The Southern Ocean dolphins... are actually really good bio-indicators of ocean health," she says.

"Some of the recent contaminant work we've done on spectacle porpoises has actually shown some rather high elevated levels of various contaminants that we weren't expecting. 

"It's going to be interesting to see how this hourglass dolphin compares to some of the other Southern Ocean species that we've looked at."

Stockin says they intend to keep the body as intact as possible before it's returned to the rūnanga.

Tohunga tohorā Ramari Stewart. Source: 1 NEWS

Tohunga tohorā Ramari Stewart, Ngāti Awa, has spent her life with marine mammals, and this year received a Queen's Honour for her work.

She's working with the Massey team on the autopsy and says strandings are one of the best ways to learn more about the whales and dolphins living around Aotearoa.

"I've been very involved in the last 26 years just supporting iwi, getting them to be able to recover resources for customary purposes," she says.

"But I'm also encouraging Māori at the same time, to learn something about their whales that occur in the rohe (territory).

"We were once the only ones on the beach. Our customary activities with whales suddenly became criminalised by the Marine Mammal Protection Act in 1978," she says. 

"And it meant that we couldn't have a relationship any longer with live or dead whales."

Since then, Stewart says things have changed and western science has "finally caught up" when it comes to marine mammals.

"It's not that long ago where there was just no one out there. Now today I was standing amongst this wonderful line-up of young women who were doing research on marine mammals," she says.

"But I want to see iwi alongside them having conversations. 

"And I also want runanga, who are the tribal authority that has the partnership with the Crown, I want to see them well informed about those animals that strand in their rohe."