The body of a juvenile dolphin, believed to be a Maui dolphin, washed up on an Auckland, New Zealand, beach on Wednesday. The Department of Conservation (DOC) said a member of the public found the dead dolphin at Karioitahi Beach.

Staff from the DOC measured and photographed the dolphin before removing it. Officials said the body of the dolphin had been lying on the beach for some time now and had completely decomposed. DOC Marine Species and Threats Manager Ian Angus said it’s not likely that a necropsy will be able to determine the cause of death.

However, the dolphin's decomposed remains will be sent to Massey University for examination.

"If confirmed, it will be the third MÄui dolphin death to be reported to DOC this year. The previous two were found to have died from natural causes," Angus reportedly said.

Maui is one of the rarest and smallest dolphins in the world, with a population of about 75. Due to their less number, Maui dolphins are critically endangered and are only found on the West Coast of North Island. There have been five recorded deaths since 2008. This is the third death reported this year.

In October, a pregnant Maui female dolphin was found dead near Te Akau, north of Raglan, New Zealand. Tests showed it died from blood poisoning resulting from complications while giving birth. Another Maui dolphin was found dead at Port Waikato. It is believed that it was a victim of shark predation.

"It’s tragic to have another juvenile dolphin die. We are hoping an examination may help us better understand why this has happened," Angus said. "We urge the public to report any sightings or deaths as soon as possible. Every dead dolphin that can’t be necropsied is a lost opportunity to understand what is threatening the dolphins."

Department of Conservation representative Lucy Roberts said it was tragic that one more dolphin has died.

"The Maui dolphin population is very small - 55 to 75 individuals - the population only grows by about 2 percent a year, which means that with approximately five individuals, there is only individual a year increase, so by losing one, it's a huge impact," Roberts said.

Here are some quick facts about Maui dolphins:

1. Maui dolphins look different to other dolphins as they are the only New Zealand dolphins, other than Hector dolphins, with a rounded black dorsal fin. Other dolphins usually have a sickle-shaped fin.

2. Maui dolphin has distinctive grey, white and black markings and a short snout.

3. Their scientific name is Cephalorhynchus hectori maui.

4. They only live up to 20 years.

5. Maui dolphins may only be able to grow their population by 2 percent a year.

6. They are under threat from net fishing and oil exploration.