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Mass Stranding: Hundreds of Pilot Whales Returned to the Water
Update: Feb. 12, 9 a.m. ET: This morning (Feb. 12), most of the 240 or so whales that had re-stranded yesterday near the original stranding site made there way back out to the shallow water during the high tide, according to the New Zealand Department of Conservation. Then, this afternoon local time, the remaining 17 whales on the beach were refloated and sent back into the deeper waters in Golden Bay.
"The animals can only be moved while floating so work with animals is dependent on tides," the DOC's Herb Christophers told Live Science. "While the tide is out, the whales are kept cool and maintained as much as possible in an upright position. They have trouble bearing their own weight and suffocate sometimes because of the position they find themselves in when stranded."
"Two boats were used to guide the 17 whales out to rejoin the original diffuse pod, and it is hoped that they will find a way into deeper, safer waters," the DOC said in a statement.
Update: Feb. 11, 9:15 a.m. ET: This morning (Feb. 11), about 100 pilot whales were on the beach, and DOC staff didn't know where the whales that had been re-floated yesterday ended up. They made another refloating attempt at 11:30 a.m. local time, managing to re-float the remaining whales. Volunteers, including those from the marine mammal charity organization Project Jonah, went into the water to prevent the whales from landing on the beach again: "There are 100 volunteers making a human chain in neck deep water endeavouring to prevent the whales restranding, with around another 200 volunteers on the beach," the DOC said in a statement. By 2:20 p.m., 80 of the re-floated whales had joined the pod of 200 or so individuals that had been re-floated yesterday. Boats are out monitoring their movements. The other 20 whales restranded and aren't in good condition; these whales will be euthanized, according to the DOC.
"It was a tough call to make and the decision not to attempt to refloat them and to euthanise the remaining whales was taken after talking to New Zealand Project Jonah's Daren Grover," the DOC said. "Unsuccessful attempts at refloating the whales would likely lead to more injury and stress to them and prolong the whales' suffering. DOC has taken the decision to humanely euthanise the whales out of concern for their welfare."
Late this afternoon (Feb. 11), local time, the 200 refloated pilot whales restranded near the original site, and the DOC is calling for more volunteers to help with more refloating attempts.
Original story (posted Feb. 10)
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More than 400 pilot whales stranded on a beach in New Zealand overnight, with 250 to 300 of the cetaceans already dead this morning in what is considered the third-largest whale beaching in the country since record-keeping began in the 1800s.
A New Zealand Department of Conservation worker saw the whales in the water Thursday night (Feb. 9) local time, finding the whales sprawled across the beach this morning along Farewell Spit, a narrow strip of land on the South Island.
More than 500 volunteers have come out to help with the rescue effort, with images showing people pouring water on the whales and covering them with what look like ripped T-shirts. [See Photos of Whales and Sharks from Above]
DOC staff and volunteers tried to refloat more than 100 of the live whales when the tide came in at 10:30 a.m. local time today (Feb. 10); about 50 whales swam into the bay successfully, while 80 to 90 of them re-stranded on the beach, according to a statement by the DOC.
Another refloating attempt is scheduled for Saturday (Feb. 11) at noon, during high tide, according to the DOC. The staff don't interact with the whales when it's dark for safety reasons: Pilot whales can get agitated when they're stressed and a flick of a fin or tail can injure or even kill a human, the DOC said. "They also carry diseases, so people need to avoid contact with blowhole exhalent or body fluids," the DOC said.
As for why whales land themselves on the beach and in large groups is a mystery, with a number of theories put forth by marine mammal experts, from malfunctions to their onboard "GPS," to a genetic pull toward the land, to a follow-the-pod-leader behavior.
Pilot whales, which are social animals, are well-known for stranding in groups of just a few to several hundred individuals, according to the American Cetacean Society. This would support the idea that when one pod member gets sick and ends up on dry land, the others swim to its aid, according to the DOC.
A member of the dolphin family, pilot whales use echolocation to get around, and if that ability is disrupted it could also lead to a stranding. "The most likely hypothesis is that pilot whales' echolocation is not well-suited to shallow, gently sloping waters, because they generally prefer high relief (steep) areas such as the edge of the continental shelf," according to a DOC fact sheet. "This would also explain why most mass strandings happen in summer, when the whales follow popular food sources inshore."
And Farewell Spit is located on the north end of Golden Bay, a known hotspot for pilot whale strandings.
The largest mass stranding of pilot whales in New Zealand occurred at another hotspot — Chatham Islands, where 1,000 whales stranded in 1918, and then in 1985, some 450 individuals landed on the beach.
NASA scientists have launched a study of a more far-out idea: that solar storms mess with the internal compasses of whales and dolphins, leading to stranding events.
Experts at Massey University are expected to undertake animal autopsies, or necropsies, of some of the pilot whales today, according to the DOC.
Due to the stranding, the Civil Aviation Authority of New Zealand is restricting airspace over the Farewell Spit Nature Reserve, barring any planes, drones or helicopters from flying under 2,000 feet (600 meters) there.
Original article on Live Science.
Jeanna Bryner is managing editor of Scientific American. Previously she was editor in chief of Live Science and, prior to that, an editor at Scholastic's Science World magazine. Bryner has an English degree from Salisbury University, a master's degree in biogeochemistry and environmental sciences from the University of Maryland and a graduate science journalism degree from New York University. She has worked as a biologist in Florida, where she monitored wetlands and did field surveys for endangered species, including the gorgeous Florida Scrub Jay. She also received an ocean sciences journalism fellowship from the Woods Hole Oceanographic Institution. She is a firm believer that science is for everyone and that just about everything can be viewed through the lens of science.