Two more dead Hector's dolphins found on West Coast and Southland

Two more Hector's dolphins have been found dead on South Island beaches. Photo / Supplied

Two more Hector's dolphins have been found dead on South Island beaches.

One dolphin was discovered just south of Greymouth last Monday, and a second at Tiwai on Saturday.

Department of Conservation marine species manager Katie Clemens-Seely said the adult dolphin found at Greymouth was very decomposed with only the spine and tail remaining when it was discovered.

It would be impossible to say what caused its death, she said.

By the time DOC was alerted, the remains could not be found - presumably, they had been washed back out to sea.

The Tiwai dolphin also appeared to be an adult and has been collected by DOC staff to send to Massey University for examination.

"Sadly, this makes 14 Hector's dolphins found dead around the South Island since early November 2021," Clemens-Seely said.

"At this stage we don't know why we've had this many Hector's dolphins wash up over the past four months. We're waiting for the remaining necropsy results to understand more about possible causes of death."

Eight of the recent deaths were calves. A decomposed and scavenged Māui dolphin was also found at Muriwai, west of Auckland, on Christmas Day but it was not collected.

Twelve of the dolphins have been sent to Massey University. When deceased dolphins are reported and retrieved quickly, they can be chilled and sent to the pathologist.

"They are gradually being examined by the pathologist. We've received results from necropsies on four calves, but a definite diagnosis wasn't possible due to decomposition," she says.

"Maternal separation, potentially during storm conditions, has been cited as the possible cause of death of those four calves."

Results have also been received for an adult female found near Hokitika on November 28.

Age-related disease has been cited as the probable cause of death. The other dolphins collected since November are 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.

"We urge anyone finding a dead Hector's or Māui dolphin to report it to DOC via 0800 DOC HOT. It is also important for the public to report live sightings via the DOC webpage, or the hotline."