Pearl Mussel Distribution for Habitats Directive (Council Directive 92/43/EEC) Reporting under Article 17.

This dataset comprises of a collation of records of pearl mussels from Welsh rivers. This dataset is a compilation of numerous records from different sources complied for Habitats Directive Article 17 reporting, related to freshwater pearl mussels Margaritifera margaritifera. Every six years, Member States of the European Union are required (by Article 17 of the Directive) to report on implementation of the Habitats Directive. The reporting format set by the European Commission requires a separate analysis for each species and each habitat in each biogeographic region which that country covers. This dataset comprises of Environment Agency and Countryside Council for Wales surveys.