One Weekend; Two Mass Strandings in New Zealand

About 145 black-bodied whales laid out on a long, sandy beach when two hikers, Liz Carson and Julian Ripoll, stumbled upon them as they were heading back to their campground.

There were long-finned pilot whales struggling on the beach for as long as their eyes could see on the evening of Saturday, November 24, 2018. The whales’ own body weight was becoming too much for their organs because of lack of buoyancy on land—resulting in asphyxiation. These pilot whales belonged to two different pods that had stranded themselves about two kilometres apart.

There was no one else around and no cell service for the hikers to call for help. In a moment of desperation, they attempted to re-float the whales on their own but to no avail. The whales were too heavy.

“There was nothing we could do but look at them. We put a hand on their heads and prayed for the first time in my life. Their tears slid down cutting through the sand, their clicks and cries growing softer,” wrote Carson in an article she wrote on Stuff.

Please note that professionals and volunteer responders undergo thorough training to analyze each stranding and respond accordingly for their own safety and that of the whales. In case of a species with a high degree of group cohesion, individuals might continue to beach until or unless they are all re-floated at the same time, strategically. As a general rule, at least two people should be there to re-float one whale and one should never drag the animal by its tail or fins so as to not cause long-term damage.

While Carson stayed with the whales, Ripoll ran to alert the Department of Conservation (DOC) at the nearest field base. By the time DOC officers got there, about half the whales had already died.

“Sadly, the likelihood of being able to successfully re-float the remaining whales was extremely low,” said Ren Leppens, DOC Rakiura Operations Manager.

Because of the remoteness of the area, lack of personnel available to help as well as the deteriorating condition of the remaining whales, the DOC decided to euthanize them to put an end to their sufferings.

Long-finned pilot whales are 5 to 6-metre long and are from the dolphin family. Just like other toothed whales like killer whales, they use echolocation to navigate and find prey. They have strong social structures, with often pods of 100-200 animals. They are also one of the most commonly stranding cetaceans around the world.

Though tragic, mass strandings are not unusual for New Zealand; they occur there every year. Stewart Island, Farewell Spit, and Chatham Islands are all hotspots for mass strandings. The largest one happened when about 1,000 pilot whales stranded on Chatham Islands in 1918. Last year, over 600 pilot whales stranded on Farewell Spit.

As DOC officers remained preoccupied with the 145 pilot whales on Stewart Island, 10 pygmy killer whales stranded at 90 Mile Beach, Northland on Sunday morning.

The department team worked with Project Jonah New Zealand (PJ) and Far North Whale Rescue (FNWR) to respond to this stranding. Out of the 10 whales, two were in bad condition when initially reported and died soon after. The DOC, PJ and FNWR teams and volunteers attempted to re-float the remaining eight the following day at high tide from Rarawa beach on the East coast after moving them closer together.

Though the team ensured that all eight whales were re-floated together for a successful attempt, two individuals kept returning to the shore in bad conditions. Both of them were eventually euthanized while the rest six remained off shore as of the afternoon of November 27, 2018.

Two individual strandings also occurred during the same weekend in New Zealand. A 15-metre male sperm whale that had stranded on a beach in Doubtful Bay, southeast of the 10 pygmy killer whales, died on Saturday night. A pygmy sperm whale was also found dead at Ohiwa on the same weekend.

At this point, officials are not considering these events to be related. However, necropsies will be performed on a few to determine the causes of death.

Possible Theories

In close-knit social species like pilot whales, if a member of the pod becomes ill or disorientated and strands, the rest of the pod often follows. According to the DOC, there are several other theories for mass strandings including: navigational errors, predation, sonar and navy exercises, earthquakes, underwater volcanoes and even magnetic anomalies.

Weather, oceanographic features of an area and unusual tides can also contribute to strandings. However, it is often difficult to pinpoint the exact cause of death as a number of factors could collectively contribute towards that.

What should you do when see a stranded cetacean?

You should contact your local authorities to report the stranding immediately.

If you see one in Québec, please contact our Québec Marine Mammal Emergency Response Network immediately at 1-877-7baleine. Mass strandings are rather rare in Québec, since the species that tend to strand the most (sperm whale and pilot whales) are rare in our waters. The biggest event happened in 1930 when about 27 long-finned pilot whales stranded near Trois-Pistoles.

Note: Stressed out cetaceans can cause injury if they start to thrash around. Stay clear of them and do not put water in their blowholes. Blowholes are their equivalent of nostrils in human beings. Water in the blowholes can cause them to die from drowning.

Sources:

On Whales Online

What NASA data can tell us about mass strandings (11/01/2018)

Could solar storms be the ones to blame for mass strandings? (17/11/2017)

What are mass strandings and what causes them? (17/08/2015)

Hundreds of whales beached in New Zealand (21/02/2017)

Elsewhere

Mass whale stranding on Stewart Island: The worst experience of my life (Stuff, 26/11/2018)

Mass pilot whale strandings at Rakiura/Stewart Island (Media Release-Department of Conservation, 26/11/2018)

Pygmy killer whales stranded in Northland (Media Release-Department of Conservation, 26/11/2018)

Why do marine mammals strand (Department of Conservation)

After spending the summer with whales off the west coast of Canada, Jasspreet Sahib is delighted to join the GREMM team as a Writing Intern this fall, through the Canadian Conservation Corps program. With a background in Marine Biology and Journalism Studies from Dalhousie University, she loves to share her passion for marine mammals and science communication with the readers of Whales Online.