On Monday, 14 young sperm whales died and washed ashore on King Island, Bass Strait. About 230 pilot whales were stranded on Ocean Beach, west of the Tasmanian town of Strahan on Wednesday. Tasmanian authorities said on Thursday they would move into “carcasses recovery and disposal operations” in the coming days. But how can you safely fly the huge beasts?
What happens to animals after they die?
If the cetaceans are left on land, where they are stranded and die, their decomposition can pose a biohazard risk, said Dr Olaf Meynecke, from Griffith University’s Center for Coastal and Marine Research. “Animal removal is an important issue and something we kind of forget about once a rescue mission is over.” In warmer climates, the internal decomposition of dead whales can lead to spontaneous eruptions. Gut bacteria in whales can multiply rapidly, producing large amounts of methane gas. “If the rest of the body is still intact — if the outer layer, the rubber, is still intact and not broken — then it can lead to an explosion,” Meynecke said. In 2004, the carcass of a 60-ton, 17-meter-long whale exploded on a busy road in the Taiwanese city of Tainan, “drenching cars and shops with blood and organs and stopping traffic for hours.” Researchers would likely conduct checks on the newly stranded animals, including necropsies to examine gut contents and assessing general indicators of health, such as the thickness of their fallopian tubes, Meynecke said. Autopsies usually can’t be done more than a few days after a whale dies, because of the risk of explosion, he says. “It’s actually part of the risk assessment … the animal needs to be assessed beforehand and if there are signs of swelling in the gut area, the pressure needs to be relieved beforehand [of the necropsy].” “If there’s one benefit, it’s that dead individuals will be an opportunity to contribute to science,” said Dr Vanessa Pirotta, a wildlife scientist working with Macquarie University, who described it as the silver lining in a sad situation. “We can learn more about their diet, their genetics, how similar these individuals were to the previously isolated population,” she says, referring to a 2020 mass stranding event in the same location that killed 350 whales. pilots.
How do you dispose of a dead whale?
Cetaceans that die on land after stranding should be towed into the ocean, Meynecke said. “They should be returned to the sea – that’s where they belong.” Sam Gerrity, of Southwest Expeditions, has been involved in the logistical effort after both the most recent and the 2020 mass blockade near Strahan. He said the disposal involved a “quite confrontational” process of towing dozens of carcasses out to sea. Dead pilot whales are towed out to sea after a mass stranding event in Tasmania in 2020. Photo: Sam Gerrity/Southwest Expeditions Open decomposition and burial were both tried after the pilot whale stranding in 2020, but authorities said they are not the preferred methods for the most recent stranding. “Our first option will be to retrieve the bodies in the deep ocean,” Incident Controller Brendan Clark said at a press conference on Thursday. But the logistics for larger whale species are much more difficult than pilot whales, which weigh up to three tons. “[For a sperm whale] we are looking at probably over 15 tons or more. Once they’re out of the water, they become too heavy to drag with normal gear,” Meynecke said. Burial of whales should be avoided, he said. “Disposing of a marine animal on land is generally not a good idea. The animals will decompose much more slowly once they are buried … it will take months and it is a very slow process.” In 2017, a New South Wales council buried an 18-tonne whale at Port Macquarie’s Nobbys Beach and then dug it up a week later due to community concerns about increased shark activity. “If you have a connection to the aquifer, there’s a chance it could leak into the ocean — it could possibly attract predators, but … that’s not fully proven,” Meynecke said. An infamous whale extermination case occurred in the US in 1970, when the Oregon highway department tried to get rid of a decaying whale by blowing it up with dynamite. “The humor of the whole situation suddenly gave way to a run for survival as huge chunks of whale were falling everywhere,” said a reporter in a television story that has now gone viral. Meynecke called the incident “proof of human stupidity. We laugh about it, but it’s the same thing as burying something – just because we can’t see it, doesn’t mean it’s gone, and just because we blow it up, doesn’t mean it’s gone – it just breaks into smaller pieces and creates more problems ».
What caused the mass stranding of whales?
Why mass strandings of whales occur is still not entirely clear. Pilot whales – misnamed as they are actually a large oceanic dolphin – are known as the most vulnerable species to mass strandings because they are highly social and form pods of several hundred. “They end up in these big groups, but they don’t know each other very well,” Meynecke said. “If one of them starts to panic … there’s a lot of miscommunication, because they don’t really know each other and the calls don’t make sense to them.” He likened it to panic among people at a concert or other crowd. “There’s this emotional stress that pushes them to constantly limit themselves.” Sperm whales, however, don’t usually congregate en masse, and the deaths of more than a dozen at King Island were alarming, Meynecke said. “It is probably not a coincidence that these two species ran aground at similar times, because they may have been searching for prey closer to the islands,” he said. “We have drastic changes in the marine environment related to climate change. This was also what was associated with the stranding of sperm whales in Europe in 2016.” This occurrence was linked to changes in water temperature and the movement of food sources to shallower waters in the North Sea. “We may see more of these hangups in the future,” Meynecke said.
