The Wadden Sea is one of the most important areas for migratory birds in the world. Around 6 million migratory birds can be found in the Wadden Sea at one time, and an average of 10-12 million pass through it in autumn and spring every year.

The amount of biomass found on mussel beds is 2,000 g per m², compared to about 65 g per m² on tidal flats.