Protection and breeding of the river mussel in Rhineland-Palatinate
Current duration: 01.09.2025 - 30.04.2026
Former project duration: 01.11.2023 - 31.08.2025
(Funded by: Struktur- und Genehmigungsdirektion (SGD) Nord des Landes Rheinland-Pfalz)
Projectwebseite: Link
Contact persons: Dr. Meike Koester & Prof. Dr. René Sahm
The long-term goal is to re-establish self-sustaining populations of river mussels (Unio crassus) in suitable water bodies in Rhineland-Palatinate. This research project contributes in achieving this ambitious goal in particular by investigating the habitat requirements of the mussels, establishing scientifically based conservation breeding and studying the requirements of juvenile mussels in terms of sediment quality and food. In general, freshwater mussels are among the most endangered species worldwide. However, healthy mussel populations in rivers provide important ecosystem services, for example by filtering large amounts of particulate material from the water and loosening the water sediments, and are therefore extremely important for the protection of aquatic biodiversity. The river mussel (Unio crassus), like some other freshwater mussels of the genus Unio, is therefore strictly protected (Federal Nature Conservation Act, Habitats Directive, Red List).
In Rheinland-Palatinate, the river mussel is classified as critically endangered. For sustainable protection of this species, targeted monitoring of existing populations is essential, as is a thorough understanding of its habitat requirements. Until now, habitat preferences of Unio crassus have often been inferred from those of the closely related freshwater pearl mussel (Margaritifera margaritifera). However, initial studies indicate that such analogies are insufficient, as the ecological requirements of both species differ significantly. This research project therefore aims to identify the key factors that influence population density and structure of the river mussel. Given the current state of knowledge, it is assumed that long-term conservation of remaining populations will require the support of a supplementary breeding program. The project will thus also focus on establishing and optimising a scientifically sound conservation breeding program. In addition, it will assess the potential of various river sections for the reintroduction of river mussels in the field.