Between 12 and 15 pygmy killer whales have died after a mass stranding on Ninety Mile Beach in New Zealand's Far North, the Department of Conservation said. An unknown number were refloated as staff, local iwi and volunteers worked through rough conditions, according to Stuff and other New Zealand outlets.

The whales were scattered across several kilometers of sand about 10 kilometers (6 miles) north of Hukatere, on the western side of the Aupōuri Peninsula. Strong tides, waves and fading daylight hampered the rescue.

Pygmy killer whales are rarely seen anywhere, and New Zealand sits near the southern edge of their range. Each stranding gives scientists a rare chance to learn about a species that remains poorly studied.

A Hard Rescue on an Exposed Beach

The Department of Conservation (DOC) was alerted on Thursday evening, Oct. 1, New Zealand Daylight Time, and the response continued through Friday, Oct. 2. Ninety Mile Beach is remote and exposed to the open Tasman Sea — conditions that make it difficult for rescuers to keep stranded animals wet and calm or move them back into deep water.

Joel Lauterbach, DOC's operations director for the northern North Island, said 12 to 15 of the whales had died, while an unknown number had been refloated, as reported by NewsWire, citing RNZ. "Conditions remained challenging today," he said, according to Anadolu Agency.

DOC staff worked alongside the area's three iwi, Ngāti Kuri, Ngāi Takoto and Te Aupōuri. The dead whales were being moved for burial while cultural protocols were carried out, and scientific samples were being collected.

The cause of the stranding is not known. DOC said its focus was working with iwi and gathering information to "understand the full circumstances of the stranding." No necropsy results have been reported, and officials have not said how many animals were euthanized or whether any refloated whales survived.

The Little-Known Dolphin Behind the Name

Despite the name, pygmy killer whales are not orcas — they are dolphins. They are oceanic dolphins that grow to about 8.5 feet (2.6 meters) and up to 496 pounds (225 kilograms), according to NOAA Fisheries. Their scientific name is Feresa attenuata.

They live in deep tropical and subtropical waters worldwide, roughly between 40 degrees north and 35 degrees south. In U.S. waters, they are found around Hawaii, in the northern Gulf of Mexico and in the western North Atlantic. They usually travel in groups of 12 to 50 animals and are often seen resting at the surface.

Little is known about how many exist. The species was moved from Data Deficient to Least Concern on the IUCN Red List in a 2018 assessment, but researchers still know relatively little about its behavior and population trends. In the United States, it is protected under the Marine Mammal Protection Act, and NOAA notes the species has "never been part of a declared unusual mortality event."

A Second Mass Stranding on This Coast in Eight Years

This is not the first time the species has stranded on this stretch of coast. In November 2018, 10 pygmy killer whales stranded near Te Paki Stream at the northern end of Ninety Mile Beach, 1News reported at the time. Two died on the beach, and eight were trucked about 18 kilometers to a calmer beach for refloating. Most of those later re-stranded, and only one was known to have stayed at sea.

In March 2020, four pygmy killer whales stranded at the Waipu River mouth farther south in Northland, an event the Northern Advocate described at the time as only the second recorded stranding of the species in New Zealand. DOC has recorded more than 5,000 strandings of all species nationwide since 1840.

Some international wire reports described the 2018 event as involving 12 whales at the same site. New Zealand reports from 2018 put the number at 10, near Te Paki Stream rather than Hukatere.

Mass strandings of tight-knit dolphin groups are not fully understood. Researchers have described a pattern in which healthy animals follow a sick or disoriented pod member into shallow water, but scientists have not established a cause for this event. Scientists have also suggested that gently sloping beaches like Ninety Mile Beach can make it hard for echolocating animals to sense the shoreline.

Stranding Response at Home and in the U.S.

New Zealand has one of the world's highest stranding rates. DOC responds to an average of 85 stranding incidents a year, usually involving single animals, according to its marine mammal strandings page. Most mass strandings involve long-finned pilot whales, and Farewell Spit at the top of the South Island sees them most years.

People in New Zealand who find a stranded whale or dolphin should call DOC's hotline at 0800 DOC HOT (0800 362 468) and avoid moving the animal on their own.

U.S. readers can see the same species off Hawaii and in the Gulf of Mexico. NOAA Fisheries asks anyone who finds a stranded marine mammal to stay at least 50 yards (150 feet) back, keep pets away, and report it to a regional stranding hotline. Touching or pushing an animal back into the water can injure it and the person trying to help.

What happens next depends on the samples collected on the beach. Tissue analysis may help explain whether disease, injury, or another factor played a role, though many strandings never receive a clear answer. For now, the loss of up to 15 animals from a rarely seen species adds to a short list of New Zealand records for pygmy killer whales.

What Readers Want to Know

What happened on Ninety Mile Beach? About 15 pygmy killer whales stranded north of Hukatere in New Zealand's Far North starting Thursday, Oct. 1. Between 12 and 15 died, and an unknown number were refloated.

What are pygmy killer whales? They are small oceanic dolphins, not orcas, that grow to about 8.5 feet (2.6 meters) and live in deep tropical and subtropical seas worldwide.

Why did the whales strand? The cause is unknown. The Department of Conservation is gathering information, and samples were collected from the dead animals.

Has this happened before? Yes. In November 2018, 10 pygmy killer whales stranded near Te Paki Stream at the northern end of the same beach.

Are pygmy killer whales endangered? No. They are listed as Least Concern by the IUCN, though scientists know relatively little about their populations.

What should I do if I find a stranded whale or dolphin? In New Zealand, call 0800 DOC HOT. In the U.S., stay at least 50 yards back, keep pets away and report it to NOAA Fisheries' regional stranding hotline.