Are the stranded whales related?
The five whales beached on England’s east coast this week are all juvenile males that were probably part of a bachelor pod, says Rob Deaville at the Institute of Zoology in London.
Deaville manages the UK Cetacean Strandings Investigation Programme (CSIP), which investigates whales, dolphins and porpoises that wash up on UK shores. He has been studying the whales on site this week.
Since 11 January, 12 sperm whales have washed up on the Dutch island of Texel and the German islands of Wangerooge and Helgoland. It’s likely that they would have been part of the same social group, Deaville says. Bachelor pods are close-knit groups of young males, but not all blood relatives.
How common are such strandings?
Around 600 cetaceans become beached in the UK each year, most of them porpoises and dolphins. In 2014, about 60 bigger whales were stranded, including 20 long-finned pilot whales, 15 minke whales, and one humpback, one orca and one beluga whale.
Why do whales become stranded?
Whales can become beached after they die, although most dead whales decompose or are scavenged at sea, before sinking to the bottom.
The causes of live strandings aren’t always clear. Whales sometimes become stranded after being hit by ships or entangled in fishing lines or nets. Pollution and marine noise have also been implicated in mass strandings.
Sperm whales aren’t normally found in the North Sea, where it is relatively shallow and hard to find squid, their main food. Mammals can’t drink seawater, so they get all their water from food. If they can’t find food, they become hungry and dehydrated.
The whales on England’s east coast died after becoming stranded, says Deaville, but why they strayed into the North Sea is unclear. The whales he has examined had little in their stomachs beside a few squid beaks eaten some time ago. Their intestines were stained green from bile, another sign they hadn’t fed in a while.
Shallow water also impairs the sonar that whales use for navigation, possibly making them more confused and more likely to beach.
What happens to whales when they beach?
Whales’ enormous mass is normally supported by water. When they are beached, the weight of their bodies damages their internal organs and muscles. The protein myoglobin is released from the muscles into the blood and reaches the kidneys, where it is highly toxic. Dehydration and kidney damage are the most common causes of death.
Once they die, the whales start to decompose, producing a stench that attracts scavengers, and causing gas to build up inside their insulating blubber.
“They act like pressure cookers,” says Deaville. “One of them exploded when we opened it up.”
Can beached whales be saved?
Once whales have been stranded for an hour, the damage to their kidneys is irreversible. If they get back into the sea, their blood can circulate more freely, but this carries even more myoglobin to the kidneys.
But humanely euthanising a large whale is still not technically feasible in the UK. “We don’t have access to sufficient volumes of drugs and we don’t have access to more physical means of euthanasia,” says Deaville. “At the moment all that can be done is to let nature take its course.”
In 2002, 45 pilot whales that stranded on Cape Cod in Massachusetts were pushed back into the ocean. The next day, they beached again, and those still alive had to be put down.
What happens to the bodies?
Once the CSIP has concluded its post-mortem investigation, it is the responsibility of the local council to remove the carcass. Usually, they are cut up and taken to landfill, rendered or incinerated.
One of the whales has washed up on land owned by the UK Ministry of Defence containing unexploded ordnances, and can’t be accessed safely.
East Lindsey District Council in the UK estimated that it cost about £10,000 to dispose of a beached sperm whale in 2012. In some countries, beached whales are towed out to sea or exploded.
Can you get valuable ambergris from beached whales?
Ambergris, a waxy substance prized for manufacturing perfumes, comes from whales’ intestinal secretions. But it has to float at sea for years before it becomes valuable. So the answer is no.
Can beached whales be eaten?
It’s not recommended. Whale meat and blubber can contain botulism toxins.
What was the largest ever whale stranding?
In 2015, 337 whales were stranded in a remote fjord in Patagonia, Chile. The cause remains unknown.