Wetenschap - 25 augustus 2016

Lots of rubbish in beached sperm whales

tekst:
Roelof Kleis

Some of the sperm whales that got beached on the Dutch North Sea coast earlier this year had quite a bit of garbage ‘on board’. As much as 25 kilos of rubbish was found in one whale’s stomach, shows a study by Imares and other institutes.

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Earlier this year six sperm whales got stranded on the island of Texel. In the same period another 24 sperm whales washed up on the North Sea coasts of England, France, Germany and Denmark. Of all the 30 stranded sperm whales, 22 were examined for the presence of rubbish. Three quarters of the waste found turned out to be fishing-related: nets, rope, and a large fishing hook. The rest was more generic waste such as plastic bags, agricultural plastic, a plastic bucket, coffee capsules and duct tape. The whale with the most rubbish in its stomach was one that got beached in France. It had swallowed 25 kilos of (mainly) plastic waste, including a fishing net of 13.5 by 1.2 metres. The most bizarre item, a piece of a car hood 68 by 24 centimetres, was found in the stomach of a sperm whale that was beached in Germany. It came off a Ford SUV.

In an ideal world of course there wouldn’t be any rubbish inside an animal like this. But not a single sperm whale died of it.
Biologist Mardik Leopold of Imares

Biologist Mardik Leopold of Imares is cautious about drawing any conclusions. ‘In an ideal world of course there wouldn’t be any rubbish inside an animal like this. But not a single sperm whale died of it.’ All the animals were healthy and there was no internal bleeding that could have been caused by the waste. ‘Their stomachs are as big as a human adult. So on the whole no harm is done.’

That does not mean there is no risk, however. According to Leopold, sperm whales regularly vomit up indigestible parts of their food. ‘Nets can be dangerous in that sense. There is a risk that a net can get stuck behind the teeth. Waste can also lead to constipation with all the risks that entails.’


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