Hector's dolphin found dead on Christchurch beach - the twelfth to be found in the South Island

Tuesday, 22 March 2022

WWF NZ researcher Amanda Leathers explains why Hector's and Māui dolphin are on the brink of extinction. (First published May 9, 2019)

An adult Hector’s dolphin, found dead on a Christchurch beach over the weekend, is the twelfth of its kind to have washed up on a South Island beach over the past four months.

A member of the public found the dead dolphin on New Brighton Beach on Saturday.

There were no obvious marks on the dolphin’s body, and it was “too early to say” how it had died, though it appeared to have died recently, Department of Conservation (DOC) aquatic director Elizabeth Heeg said.

The smallest dolphins in the world, Hector’s dolphins are only found in New Zealand waters and are considered nationally vulnerable, with a population of about 15,000.

* Body of dead Māui dolphin wasn't picked up because email went to off-duty ranger

* Four Hector's dolphins, including three calves, found dead on South Island beaches

Hector’s dolphins are only found in New Zealand waters and are considered nationally vulnerable. (File photo)

DOC staff collected the dolphin, and it was sent to Massey University where a necropsy would be done to determine the cause.

“From necropsies done by the Massey team, we can glean really valuable information about this species and the threats they face,” Heeg said.

It was the twelth Hector’s dolphin found dead around the South Island since November, eight of which were calves.

Ten of the dolphins had been sent to Massey University.

The body of a critically endangered Māui dolphin was also found decomposing and scavenged in Auckland on Christmas Day. It was later found the body was not recovered for testing because an email was sent to the wrong person.

The person who found the carcass sent an email reporting the find to a DOC ranger who was on holiday and didn’t see the message until the middle of January, DOC marine technical advisor Kristina Hillock said.

By that time, the corpse had washed out with the tide.

“At this stage we don’t know why we’ve had this many Hector’s dolphins wash up over the past four months, and we will need to await the remaining necropsy results to understand more about possible causes of death,” Heeg said.

Necropsy results for three calves had not given a definite diagnosis due to decomposition. However, maternal separation, potentially during storm conditions, were cited as the possible cause of death.

Age-related disease was cited as the probable cause of death for an adult female found near Hokitika on November 28, while others were still under investigation.

“The information from the necropsies will help us build our understanding of Hector’s and Māui dolphins and help with future planning for marine protection and management,” Heeg said.

Further information would be uploaded to DOC’s incident database.

When dolphins were reported and collected quickly, they could be chilled and sent to a pathologist, increasing the amount and value of information that can be obtained.

Heeg urged anyone who came across a dead Hector’s or Māui dolphin to report it to DOC on 0800 DOC HOT.