Sperm Whales Stranded in Germany in 2016: What the Plastic Showed

In the first weeks of 2016, young male sperm whales began stranding on North Sea coasts in an event that experts called highly unusual. By spring, 29 animals had been found dead or dying in Germany, the Netherlands, the United Kingdom and France. When German scientists examined the carcasses, they found something that shocked the public: four of the whales had large amounts of plastic in their stomachs, including a 13-metre fishing net and part of a car engine cover.

The finding became one of the most widely shared environmental stories of the decade, and it is often retold with exaggerations. Here is what the necropsies actually showed, why the whales died, why they ended up in the North Sea at all, and what the case tells us about plastic in the ocean.

What happened in early 2016

From January 2016, sperm whales stranded on beaches and sandbanks around the southern North Sea. The Common Wadden Sea Secretariat counted 29 animals: 19 recovered in the Wadden Sea area of Germany and the Netherlands, two near the German island of Helgoland, six in the Wash on England's east coast and one on the French coast near Calais. Some of the most widely circulated photographs were taken at Skegness in Lincolnshire.

All the animals were young males of similar age, size and weight, roughly 10 to 15 years old, which suggests they were travelling together as a group. Strandings of sperm whales in the North Sea are not new; they have been recorded since the 16th century, but in recent decades they have usually involved one or two animals a year, mostly in Denmark. The last comparable event was in 1996 and 1997, when groups of 16 and 13 sperm whales stranded on the Danish island of Rømø.

What scientists found in their stomachs

Thirteen of the whales came ashore in the German state of Schleswig-Holstein, and a team led by Professor Ursula Siebert of the University of Veterinary Medicine Hannover examined them. In four, the stomachs contained large amounts of marine litter. The items included a shrimp fishing net about 13 metres long, a plastic engine cover from a car, the remains of a plastic bucket and other pieces of plastic waste.

The stomachs also held thousands of squid beaks, the hard mouthparts that remain after squid are digested. That matters, because it shows the whales had been feeding well. Siebert said the litter had not caused the strandings directly, but that it could have led to digestive problems if the whales had survived.

The state's environment minister at the time, Robert Habeck, posed with some of the debris and summed up the public mood: "These findings show us the results of our plastic-oriented society." The image of a car part inside a whale became a symbol of how far our waste travels.

Why did the whales die?

The plastic did not kill them. Sperm whales are built for deep water, where the sea supports their weight. In shallow water and on sandbanks, a whale weighing many tonnes is crushed by its own body. The leading explanation from the investigators is that the animals' weight compressed their chests, collapsing their airways and disrupting blood flow, which led to heart and circulatory failure. Whales lying on their sides may also have had their blowholes covered by water.

National Geographic reported the same conclusion in March 2016: the whales most likely died of heart failure after straying into shallow seas they could not navigate. As for what drew them there, the Wadden Sea Secretariat described the precise cause of the strandings as still unclear later that year.

How sperm whales end up in the North Sea

Sperm whales are the largest toothed predators on Earth. Adult males average about 16 metres and 45 tonnes. They hunt mainly medium-sized squid, usually diving 300 to 800 metres and sometimes far deeper, and can stay under for more than an hour.

Females and young stay in warmer waters, while males, once they mature, head to colder, food-rich waters at higher latitudes. According to the Wadden Sea Secretariat, these whales appear to have strayed from their route between the Azores and feeding grounds off Norway. The North Sea, which is shallow and has a sloping, sandy floor, is a trap for animals that use echolocation and are used to deep water.

Scientists have suggested several reasons why a group might take the wrong turn: following squid into the North Sea, shifts in sea temperature and prey distribution, storms, or disturbance from human activity. Danny Groves of Whale and Dolphin Conservation told National Geographic that the whales may have become disoriented while chasing squid, and added that the exact cause may never be known.

How plastic harms whales

Even though plastic did not cause these deaths, the finds are a real warning. Sperm whales, beaked whales and baleen whales all swallow plastic, either by mistaking it for prey or by eating prey that contains it. Large items such as nets and sheets can block the stomach, cause ulcers or leave the animal feeling full while it starves. Smaller fragments may cause slower, chronic harm.

Plastic has been found in sperm whale stomachs since at least the 1970s and has been linked to several deaths. In April 2019, a sperm whale found dead off Sardinia had about 22 kilograms of plastic in its stomach, and WWF noted that plastic had killed five whales in the previous two years. An earlier case often cited by researchers is a young sperm whale found dead near the Greek island of Mykonos in 2011, reportedly with dozens of plastic bags in its stomach.

Fishing gear is a major part of the problem. Lost and discarded nets, often called ghost nets, are the largest ocean-based source of plastic debris and make up a large share of the big items floating at sea. The net found inside one of the German whales is a good example of the kind of litter that threatens large marine animals.

Correcting the viral version

This story has been recycled many times since 2016, sometimes with headlines claiming that "two whales" were found in Germany "full of car parts". Fact-checkers at Lead Stories examined that version in 2019 and pointed out several problems:

• The strandings happened in 2016, not in the year the posts reappeared.
• There were 29 whales across four countries, not two whales in Germany.
• Only four of the 13 whales examined in Germany had large amounts of plastic, and only one car-related item, an engine cover, was confirmed.
• The plastic was not the cause of death.

Another figure often attached to the story says that 80% of plastic thrown away on land ends up in the ocean. That is a misreading. One widely quoted study estimated that roughly 80% of ocean plastic comes from land-based sources, which is a very different claim. Estimates of how much plastic reaches the sea vary widely, but recent reviews put leakage into rivers, lakes and seas at around 19 to 23 million tonnes a year, which is serious enough without exaggeration.

This site later published a fuller account of the 29 sperm whales stranded around the North Sea in 2016.

What actually helps

The whales of 2016 were not killed by our rubbish, but the contents of their stomachs show how far it travels, reaching animals that feed hundreds of metres below the surface. The most effective responses are mostly unglamorous:

• Better waste collection where it is weakest, so plastic does not reach rivers and coasts in the first place.
• Gear marking and net recovery schemes in fisheries, plus port facilities where old nets can be returned and recycled.
• Fewer single-use plastics and products designed to be reused or recycled.
• Beach and river clean-ups, which remove debris and also produce useful data on what is polluting a coastline.
• Supporting stranding networks, whose necropsies, like the German investigation, tell us what is really happening to whales.

Sperm whales are listed as Vulnerable by the IUCN. They survived centuries of industrial whaling, which only wound down in the late 1980s, and now face ship strikes, entanglement, noise and pollution. Keeping plastic out of their food chain is one of the threats humans can actually control.

Sources: Common Wadden Sea Secretariat: Cause of sperm whale strandings is still unclear; Nationalpark Schleswig-Holsteinisches Wattenmeer: press release on the necropsies; National Geographic, March 2016: Dead whales found with car parts and plastics in their stomachs; Lead Stories, February 2019: fact check; Wikipedia: Sperm whale; Wikipedia: Marine plastic pollution; original report: True Activist.

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