Are there more than others?


NOS News

  • Ivo Landman

    editor online

  • Ivo Landman

    editor online

Three whales swimming up the Seine, beaked whales washing ashore in Zandvoort, Belgium and Denmark, a humpback whale on Vlieland and then about three wandering walruses off Norway and in the Baltic Sea. Every year a few marine mammals end up going wrong, but this year it seems to be a lot.

The last in the series is a white whale that has swum up the Seine. That animal usually lives in arctic regions, but sometimes they wander away. An orca was also spotted in the French River in May and a minke whale appeared last month.

White dolphin in the Seine near Paris

Marine mammals in rivers are rare, and three in a row is quite bizarre, says Nathalie Houtman from the World Wide Fund for Nature. Killer whales and minke whales do not normally live in fresh water. Belugas sometimes swim into the mouth of a river, but especially in Canada. “Sometimes you see a marine mammal in a river, but it’s often short-lived. It’s not their natural habitat.”

The SOS Dolfijn hotline has actually seen the number of reports increase for years. However, this does not immediately mean that more animals are washed ashore, says a spokesman. “More people are also reported because more people have a phone with them than before.”

The strandings in the Netherlands are kept up to date at Guido Keijl has been doing this for Naturalis for more than ten years, but the washed-up marine mammals have been counted for much longer: the oldest observations date back to the 13th century. Even back then, Keijl notes, whale species that did not belong here occasionally washed ashore.

According to him, the number of strandings is different every year. Since 2000, it has varied from 3 to 16 per year (apart from the more than 10,000 guinea pigs):

Stranded whales and dolphins in the Netherlands since 2000

More than 98 percent of the washed-up whales are porpoises, which (like minke whales) occur naturally in the North Sea. It is also not always clear to the other marine mammals why they end up in the relatively shallow and murky North Sea. It varies by species. Fin whales, for example, sometimes collide with a ship in the Bay of Biscay, the one at Keijl, and if such a carcass hangs on the bow, it is taken with that ship to our coastal waters.

More often, it involves marine mammals that have lost their way in search of food. Climate change also has an influence on this, although it is difficult to say how much.

On July 19, bathers managed to escort stranded beaked whales back to sea:

  • Beachgoers push bottlenose dolphin back towards the sea

  • Visser films jumping humpback whales off the coast of Zeeland

Steve Geelhoed, researcher at Wageningen Marine Research, has noticed that in recent years more and more different species have been stranded on European shores. Live animals such as pilot whales are also seen more often.

The humpback usually manages to survive in the North Sea, but there are also species that traditionally do not belong here. The possible reason is the stronger melting of the sea ice further north in the summer, explains Geelhoed. “Whales that live there look for food along the edges of the ice, where higher concentrations of food can be found. Without sea ice, they look for new feeding grounds and sometimes migrate.”

A further problem is that dolphins and (toothed) whales such as the sperm whale use sonar to scan for obstacles. “The North Sea is shallow with a sloping bottom so they don’t get a signal back and they think there are no obstacles and before you know it they’re on the beach.”

Once washed ashore, it often does not end well. Even if it is possible to get the animals back into the sea, they often get lost again and wash up on, for example, the English coast.

Wind farms at sea

According to Nathalie Houtman from the World Wildlife Fund, whales, like other marine life, suffer from human activity. Shipping, fishing and climate change.

Some also point to the advancing wind farms in the sea, which make a low-frequency noise. But if stray marine mammals end up there, they have already missed a turn somewhere, notes researcher Geelhoed. “Also, their own sonar makes a sound at higher frequencies, so they are not aware of that hum.”

According to Keijl, the wind farms even have a pleasant side effect: Fishing is not allowed, so there can be nurseries for fish. “And that’s good news for seals, dolphins and whales.”

Leave a Comment