It was when Karin Tyrefors was out with her dog and walking along the beach at Brandalsund that she discovered a different mussel.
- You are used to seeing these small shells.
When a large, powerful mussel with both halves intact appears, I reacted, she says.
After some research, it turned out to be the invasive species of American trawl that normally belongs in Mexico.
"Fits perfectly in pasta"
Together with Nils Kautsky, professor of ecotexology at Stockholm University, she has now visited the site several times.
They have also found the mussel at Torpaviken and it has probably established itself in the area.
- We will not be able to prevent it from being here.
It will spread once it has come here, so now we have to learn more from it, says Nils Kautsky who also believes that it is edible.
- It would probably fit perfectly in a Pasta vongole, he says.
Follow when Professor Nils Kautsky collects the mussels at Brandalsund and tells more about how they can affect the local environment in the video above.