A model approach to estimate the potential for mussel beds in a Wadden Sea area of the German North Sea coast

In the awareness of the increasing conciousness regarding the sensitivity, vulnerability, and
complexity of near coastal marine ecosystems, including tidal flats, it is imperative to improve the
understanding of its individual elements. One of these elements are organisms habitating the
seabed, such as mussels.
Bivalves - specifically blue mussels (Mytilus edulis) and pacific oysters (Magallana gigas) - besides
other smaller organisms are an integral part of the seabed fauna. On the one hand they serve as a
basic food resource for a large number of higher trophic level predator. On the other hand they
affect the surface structure, stability and composition of the seabed.
To better understand the large fluctuations the mussel stocks underwent during the last decades, it is
of great benefit to know the environmental conditions of their habitats. Based on the analysis of
different physical parameters at known mussel beds, prototypical automated algorithms were
developed and used to identify other tidal flat regions with favorable conditions for epibenthic
mussels. The input parameters originate from different morphological, hydrodynamical,
sedimentological and hydrochemical numerical models. Morphological factors include
morphological activity and gradient conditions of the ground surface, hydrodynamical factors
include stream velocities, bottom shear stress, wave orbital velocities, energy of wave breaking and
duration of tidal flats falling dry during low tide, sedimentological factors include sediment
composition and hydrochemical factors include salinity. These parameters were available as
products of the mFUND project EasyGSH-DB and were supplemented with additional evaluations.
It is expected that the approach of habitat modeling will allow to determine the possibility of initial
and long-term settlements of epibenthic mussels by ruling out intertidal or subtidal seabed areas
where environmental parameter combinations do not fulfill the necessary requirements.