In another sad turn of events, a further eight sperm whales have been found dead along the coast of Germany, alongside a possible ninth on the north coast of France.
This unfortunate news follows a flurry of similar reports throughout the last month, and brings the total number of these cetaceans found washed up from the North Sea to 26.
According to the Schleswig-Holstein regional environmental authority, the carcasses were discovered in the Wadden Sea national park, near a town called Friedrichskoog. All of them were found in close proximity to one other and were young males of a similar age to those found in other northern European spots throughout the past three weeks.
Reports of these beaching events began in early January when, within just a few days, 12 sperm whales were discovered along the shores of two German islands, Wangerooge and Helgoland, and the Dutch island of Texel. This was followed by a further five of the mammals washing up in three different spots across the east coast of England around a week ago. In addition, project manager of the U.K. Cetacean Strandings Investigation Programme (CSIP) Rob Deaville told IFLScience that reports have just surfaced of one more individual found stranded along the coast of Calais. "This is now an international, highly abnormal stranding event," he added.
At the moment, further information on the reason behind these events is scarce. It’s believed that they’re likely all from the same pod since these toothed whales are often found in groups. While females tend to stay in the tropics or subtropics year-round, breeding and caring for young, during the winter males will journey to higher latitudes, either solo or with other bachelors.
One of the whales stranded in the U.K. CSIP/ZSL
That said, sperm whales don’t usually frequent the North Sea – it’s relatively shallow and scant in their main food source, squid, which make up around 80 percent of their diet. Indeed, upon examination of one of the U.K. carcasses, nothing was found apart from a few squid beaks and bile staining, consistent with the stomach being empty for a prolonged period, Deaville said. Alongside being resource-poor for sperm whales, the shallow waters of the North Sea likely make it difficult for the animals to navigate properly as it could impede their ability to use echolocation, confusing them and causing them to end up stuck in dangerous areas.
"These animals all died because they were live stranded – that's what would have killed them," said Deaville. "But the question of why they came into the North Sea in the first place is still hanging."
Various speculations have been thrown around the Internet so far, including climate change and military sonar, which studies have suggested can interfere with echolocating animals. But even if correlations can be made, it can be extremely difficult to pinpoint a cause in events such as this. In addition, the carcasses decomposed so quickly that it has been difficult for scientists to examine them, although it should still be possible to sample for possible agents of disease like viruses.
"Another big question is whether these animals entered the North Sea together and were stranded in groups, or if we are looking at a series of entries by a number of different bachelor pods," Deaville said. "There may well be different drivers for each event."
CSIP, in collaboration with other groups in countries affected, will continue to gather data in the coming months, but whether or not this will give any meaningful answers is unknown at the moment. Members of the public are encouraged to report any strandings they come across, even of smaller cetaceans such as dolphins, as this could provide further insight to the situation.
