Whale eats millions of pieces of plastic a day – New Scientist

Bale whales ingest an estimated ten million pieces of microplastic per day. It can have harmful consequences for a group of animals that are already struggling.

Microplastics are everywhere. They are in the air, in the water and in our food. We put these tiny plastic particles in toothpaste and cosmetics, and they are released when car tires or clothes wear down, or when larger pieces of plastic break down.

Almost all animals, plants and people are exposed to microplastics. Bale whales are at extra risk of consuming a lot of it because of their diet. They feed on small marine animals such as plankton and krill, which they swallow in large quantities by filtering seawater through their finely meshed baleen. The whales also live in polluted areas.

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An American research group has now taken steps to map the amount of microplastics baleen whales consume. To do this, they studied where and how deep 191 radio-wired fin and humpback whales dive when searching for food in the California Current. It turned out that they mainly catch their meals at a depth of 50 to 250 meters, where there is also a lot of microplastic floating around.

The researchers combined this knowledge with information on how much water and prey such as plankton and krill the animals consume daily. They then examined how much microplastic is in that water and the prey.

Based on this, they were able to calculate that baleen whales off the coast of California ingest around ten million pieces of these microplastics every day. These results were published in the journal on Tuesday Nature communication.

Discretion

Side note: the results are a rough estimate with large uncertainties. The researchers have not been able to measure exactly how many plastic particles pass through the mouth of a whale every day. It is very difficult to measure exactly how much microplastic is in the loot.

‘These numbers are therefore uncertain,’ says Susanne Kühn, biologist at Wageningen Marine Research. ‘But such an estimate is the only way to get an idea of ​​whales’ plastic intake. It is difficult to examine it in a laboratory.’ Only in the rare cases where an animal washes ashore can scientists examine its stomach and intestinal contents to see how much plastic is in it.

‘The American research confirms what other studies also show,’ says Thijs Bosker, environmental scientist at Leiden University, who also researches microplastics in whales. He estimated in previous research that whales ingest three million pieces of microplastic every day. “The American research shows that the plastic in whales mainly comes from prey animals that have previously consumed microplastics themselves. We saw that too.’

Measuring scale

What are the health consequences of all that microplastic? The researchers don’t know yet. “Plastic is full of chemicals like plasticizers and flame retardants,” says Kühn. “It has been shown in laboratories that these can have harmful effects. They can, for example, cause cancer or disrupt hormones.’

In nature, where several factors play a role, it is difficult to determine what is due to plastic and what is due to climate change or changes in food. It is also not yet clear what happens in the body with ingested microplastics. Do they accumulate or get poked out, how many plasticizers and other chemicals seep out?

The only thing we know for sure is that the presence of microplastics is caused by humans. ‘Because plastic is clearly visible in the environment and in our daily lives, many people are concerned about it. It is used as a gauge for the state of the environment’, says Bosker.

‘It is good that there is a lot of attention on plastic pollution, but it is also important to put this problem into a wider context. Climate change, acidification and emptying of our oceans will probably have greater consequences for whales and the rest of the world than plastic pollution.’

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