Official shell counting day: Counting seashells on Dutch beaches for science

On Shell Counting Day, people interested in collecting shells can go to shell tables set up on 17 beaches along the Dutch coast on Saturday. Experts will be on hand to help shell collectors identify the species they find. Saturday is Shell Counting Day on the Dutch and Flemish coasts. Countings also take place in northern France.

The idea behind that action is that each participant picks up a hundred shells and writes down on a counting card which species they have found. The counting card shows examples of the most common shells found on the North Sea coast. According to the experts, mussels reveal a lot about marine life. Scientists use the data from the mussel counters to determine, for example, whether wind farms affect marine life and to study the effects of climate change.

The Netherlands has been participating in Mussel Count Day since 2022, which was previously organized in Belgium. According to the organizing institutes and the Naturalis Biodiversity Centre from Leiden, the day is a popular event. Last year, more than a thousand enthusiastic participants counted and identified almost 35,000 mussels despite the bad weather. People also went to the beaches in Belgium and France, where more than 80,000 shells were found along 400 km of the North Sea coast. Last year, the common periwinkle, cockle, and razor clam were found the most.