At SOS Dolfijn, the center for cetaceans in the North Sea, it’s all hands on deck. Since last Thursday, the dead porpoises keep washing up on the various Wadden Islands.
There are also reports of harbor porpoises washed up on the mainland of Friesland between Holwerd and Lauwersoog.
80 in a few days
“In a few days, 80 have been counted,” director Annemarie van den Berg told RTL Nieuws. And that is strikingly high.
Van den Berg explains that in a ‘calm year’ 200 dead porpoises wash ashore, and in a ‘busy year’ 900. “But this is more than usual. The Animal Ambulances just keep on driving.”
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Interestingly enough, this mainly concerns adult animals. “At Ameland there were 40”, says Van den Berg. SOS Dolphin trying to map it all out.
“Now we have had a northerly wind lately, but that peak is very striking. They are already in a state of decomposition, from which we can deduce that they died a week earlier.”
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Porpoises belong to the whale family
The porpoise is a small one in the whale family, but can still grow to 1.80 meters in length. It is the most common species in the North Sea, they like relatively cold coastal seas. They can live up to 15 years.
There are about 35,000 living in our part of the North Sea, the southern part. There are 300,000 in the entire North Sea.
In the Middle Ages, the porpoise was often eaten and the oil from the bacon layer was used in lamps and animal feed. There was a time when they were almost gone, in the 1970s and 1980s. But then they returned.
According to Ecomare, people are an enemy of the porpoise. They suffocate in fishing nets, get into trouble if they lose their habitat, or can die from pollution and noise pollution. There are also natural enemies: gray seals, dolphins and orca’.
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What’s going on? “It can be a certain disease, but it can also be caused by human actions,” says Van den Berg. “We don’t know that yet, research is needed.”
loud noises
The animals seem to have died at the same time. “Maybe it’s a virus outbreak, or it’s because of a leaking container. A wind farm is also being built and whales can die from loud noises.”
According to Van den Berg, there is also a major naval exercise in the area. “Defense says no mines exploded, but they do use sonar.”
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Utrecht University is conducting research into mortality. Researcher Lonneke IJsseldijk finds it particularly striking that the animals are found in groups, and only on a few Wadden Islands.
According to IJsseldijk, this has to do with the current. “It is likely that they will come from the same point, from the north,” says IJsseldijk. “They are in the same state of decomposition, which suggests they died at the same time.”
Illness, or something else?
How it came about is still a mystery. “Human action is one of the options we are looking at,” says IJsseldijk. “That’s because we know from previous data that human actions or noise sources result in mass stranding. But we also look at disease. The first question: are they healthy animals that died acutely, or are they animals that died weakened? “
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We won’t know exactly what happened until after the investigation. The researcher is working on a plan for this: until then, the cadavers are stored in a freezer.
The situation of the porpoises will be monitored in the near future. IJsseldijk: “The species is under pressure. There is a lot of human activity in the North Sea and that is only increasing. We are going to build large-scale wind farms, there is a lot of fishing, we have a lot of shipping. That has its consequences.”
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