A Hector's dolphin has been found dead in Fiordland for the first time since 2013.
The female was discovered by a member of the public last week on the foreshore of Piopiotahi, also known as Milford Sound, according to the Department of Conservation (DoC).
Senior ranger Richard Kinsey says the dolphin was an adult in a good condition and there were no obvious marks that might indicate why it died.
The dolphin will now be sent to the Wildbase Pathology at Massey University for a necropsy in order to determine the cause of death.
"This may be difficult because the animal has been frozen, which can obscure signs of cause of death but tests for toxoplasmosis should still be possible," he says.
Kinsey says the sighting of a Hector's dolphin in the Milford Sound is rare.
"While other dolphins such as Bottlenose dolphins are frequently seen in the fiord, the presence of Hector's dolphin in Milford Sound is highly unusual," he says.
"The last time a Hector's dolphin was reported dead in Fiordland was in 2013. A population of the dolphins live on the West Coast, but don't often come as far south as Fiordland."
It was a busy week for Hector's sightings. Earlier in the week marine mammal experts were excited at a report of a live Hector's dolphin seen near Coromandel, also outside their normal range.
A Hector's dolphin calf was also found washed up in Oamaru earlier in the week but was washed back out to sea before DoC could respond.
Hector's dolphins have a population of around 15,000 and are classified as nationally vulnerable.
Members of the public are encouraged to report Hector's dolphin incidents and sightings via the 24-hour DoC hotline, 0800 362 468.
