Ferrantia, Volume 64: Rearing of Unionoid Mussels With Special Emphasis on the Freshwater Pearl Mussel Margaritifera margaritifera

About this book

colour & b/w photos, colour & b/w illustrations, b/w maps, tables

Language: English with trilingual article abstracts in English, French, and German

The conservation of freshwater mussels is a major challenge as they belong to the most imperiled freshwater organisms worldwide. For instance from the 297 species recognized in North America, 213 are endangered, threatened, or of special concern. Freshwater mussels have an important ecological value as they improve water quality and provide nutrient and energy cycling in streams and lakes by filtering algae, bacteria, and organic matter from the water column. Extensive anthropogenic habitat alternations have led to dramatic population declines in freshwater mussels worldwide. Habitat degradation and water pollution not only harms mussel populations directly, but as the reproductive cycle of most naiads; mussels involve a fish species acting as an intermediate host, any shift or decline within the fish population has a negative indirect effect on the mussel population also.

As in North America, most European freshwater mussel species are highly threatened. The worst affected species are the freshwater pearl mussel (Margaritifera margaritifera L.) and the river mussel (Unio crassus L.). They both show a dramatic decline throughout their European distribution range. Both species are listed in Annex II of the Habitats Directive and M. margaritifera is also listed in Annex V (Directive 92/43/EEC). According to EU legislation (Directive 92/73/EEC; Directive 97/62/EEC) member states are obligated to protect and maintain the local populations of both species. Although many conservation programmes have been initiated all over Europe in the past, some mussel populations are nearing extinction. One possibility to save the genetic diversity of these autochthonous populations could be to artificially breed juvenile mussels and introduce them to their native populations in order to stabilise them. Rearing the juvenile stages of M. margaritifera under controlled conditions could help compensate for an approximate 100% loss during the initial few years.

Many attempts and methods have been used to rear Freshwater Pearl Mussels and other mussel species under laboratory or semi-natural conditions across Europe during the last decade. To discuss the progress in the field of mussel propagation, an international seminar was organised within the LIFE Nature Project “Restauration des populations de moules perlières en Ardennes – LIFE 05 NAT /L/000116″ during spring 2008. LIFE NATURE is the EU’s financial instrument for supporting nature conservation projects throughout the EU.

Many of the papers discussed during the seminar appear in this special issue of Ferrantia and include: Articles describing the dramatic decline of Margaritifera margaritifera in Germany. Ecological aspects of how to develop successful conservation strategies for the fresh water pearl mussel are presented. Semi-natural and laboratory culture and propagation methods for the freshwater pearl mussel and other species including growth factors are discussed. Questions regarding the release of captive bred animals are addressed.

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