Porpoise researcher Mardik Leopold of Wageningen University also calls it “very special” that so many porpoises have washed up on the Wadden Islands in such a short time. “We’ve never seen this before.”
According to him, you can investigate what happened in various ways: “Something hit the animals at sea, they did not die on the beach. With so-called ‘drift models’, it is possible to predict how a floating object in the sea on the basis of current currents and wind drift. sea moves. Or, in this case, what trajectory a washed-up object has traveled in the sea. Perhaps it is part of a bigger disaster, then you should see porpoises wash ashore in neighboring countries in the coming days.”
The animals that have now washed ashore can be examined in various ways, says Leopold. “In Utrecht they investigate the cause of death, they look at the general health of the animals before they died. Then they cut out the stomach, and it goes to us in Wageningen. We can then look specifically at their diet, for example if there is something crazy in their stomach.”
‘We now have to rely on ad hoc measures’
Both researchers say it will be difficult to determine exactly what caused the animals to die, because many of the harbor porpoises on the beach are already in a state of decomposition. Leopold: “We don’t really have the infrastructure in the Netherlands to properly handle a disaster like this, so we now have to rely on ad hoc measures. They are animals of 40 or 50 kilos, and they have to be refrigerated as much as possible to the mainland. be brought in. That is difficult.”
“We get good indications about the health status of the animals on the cutting table, but it does not mean that we can determine the cause of death with certainty after an autopsy,” IJsseldijk adds. “Given the state of decomposition animals are in, we may not find out at all. We can rule out some things, but the exact cause remains unclear.”
Incidentally, it is not the case that more and more porpoises are washing ashore on the Dutch coast, emphasizes IJsselijk. “2011 and 2013 were the peak years when it comes to washed up animals, after that it subsided a bit. So far this year seemed to be fairly quiet, with about 300 harbor porpoises washed up, but that could be very different now. “
–
