Cut trough shells are found in a narrow stroke along the entire North Sea coast. They rarely found any further out to sea. They are often called spisula. This shellfish is the most important source of food for the common scoter. Eiders also forage on spisula when there's not much other food to find. The shells (fresh and fossil) wash ashore in large amounts on the North Sea beaches. In southern Europe, you often find this shellfish in paella. In that case, they are usually caught elsewhere, such as the Dutch coast. There are some places where it is forbidden to fish spisula, the Voordelta in Zeeland is an example, where they shellfish are left for the birds.