Mystery as Six Dolphins Found Dead on Beach

Six dolphins have been found washed up dead on a beach in New Zealand, creating a mystery as to what caused their deaths.

The dolphins were discovered on Ruakaka Beach on New Zealand's North Island, around 80 miles north of Auckland, the country's most populous city, by locals on Sunday.

The beached bodies had gone unnoticed until 10.30 a.m. local time due to a dense layer of cloud covering the area, but were stumbled upon by local resident Richard Addis and his children.

Addis told local news The New Zealand Herald that the dolphins were between 6 and 8 feet long, and that he was "sorry to see" the pod laid out dead on the beach.

The New Zealand Department of Conservation was notified about the dead dolphins on the beach, as well as Project Jonah, a local whales and dolphin protection and rescue charity.

In a Facebook post, Project Jonah stated that the dolphins were common dolphins, or short-beaked common dolphins.

These creatures often form huge schools of several thousand individuals, and can dive to depths of over 900 feet in search of food. This species is thought to be the most common dolphin in the world, with a global population of around 6 million.

Mass strandings, as it is known when many of the same type of animal wash up at once, can occur in a variety of cetacean species.

"Strandings do occur for natural reasons—any whale that dies at sea might wash up on shore," Patrick Miller, a professor at the School of Biology at the University of St. Andrews in Scotland, previously told Newsweek.

The exact cause of death of these animals remains unknown, and according to the Project Jonah post, "the dolphins were transported to Massey University for further investigation."

Common dolphins like these washed up dead en masse in 2009 in the U.K., with 26 dolphins being found dead on the shore. This mass stranding was thought to have been caused by naval activity in the area, which may have included the use of sonar that can confuse animals who rely on a similar system for navigation and communication.

There are eight other different species of dolphins found off the New Zealand coast, including Hector's, Maui, dusky and bottlenose dolphins.

Maui and Hector's are some of the smallest species of dolphins in the world, both only reaching around 5 feet long at most. While Hector's are a vulnerable breed, with there being only around 15,000 individuals older than one year, Māui dolphins—a subspecies of Hector's—are critically endangered, with there being between just 48 and 64 older than one year.

Both species are threatened by a number of issues, including fishing, vessel strikes, oil and gas exploration, and disease, including toxoplasmosis. Toxoplasmosis is caused by the parasite Toxoplasma gondii, the only other host of which is the domestic cat.

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