Header Slideshow Image 1 of 13

Mussel monitoring

Mussel beds are among the most diverse communities in the Wadden Sea, serving as valuable food source and important habitat for birds and invertebrates.

Since 1998, these mussel beds are annually monitored within the framework of the Trilateral Monitoring and Assessment Program. Aim is a yearly overview of the composition and structure of the mussel beds to describe and evaluate their long-term development.

Surveys of mussel beds are mainly carried out between May and September. In on-site inspections, the contours of the beds are determined by GPS and the coverage is estimated using the “Stiefelmethode” (the number of steps on a zigzag shaped transect with and without mussel under the boot is counted and taken as a measure of coverage). Samples are taken to additionally determine abundance, length frequency distribution, biomass and condition index of the mussels. To document diversity of the beds, accompanying fauna samples are taken in September to analyse structure and dynamics of the endo- and epibenthic fauna at selected blue mussel bed sites. Monitoring is complemented by evaluation of digital photographs covering all intertidal blue mussel beds.

The strategy to monitor mussels has been agreed between Denmark, Germany and The Netherlands in the Trilateral Monitoring and Assessment Program (TMAG 1991) (see also (Nehls & Büttger 2006)).

The project is carried out on behalf of the "Nationalparkverwaltung Schleswig-Holsteinisches Wattenmeer".


Nehls, G. & Büttger, H. (2006): Miesmuschelmonitoring 1998-2005 im Nationalpark Schleswig-Holsteinisches Wattenmeer. Ein Projekt im Rahmen des Trilateral Monitoring and Assessment Program (TMAP), (Hrsg. BioConsult SH). Husum (DEU), Im Auftrag des Landesamtes für den Nationalpark Schleswig-Holsteinisches Wattenmeer, S: 165.

TMAG (1991): TMAP Manual. The Trilateral Monitoring and Assessment Program (TMAP). Common Wadden Sea Secretariat/Wilhelmshaven (DEU).


Hanna SchadeMarit Schütte