First record of Sinanodonta woodiana (Lea, 1834) in an artificial reservoir in the Molise region, Southeast Italy

The occurrence of the Chinese pond mussel Sinanodonta woodiana is reported for the first time in the Molise region (Southeast Italy). Details of the mussel's invasion history in Italy are also given. A total of 24 S. woodiana specimens were collected after a long drought period in October 2017 from an emerged beach on the southwest side of the Guardialfiera artificial lake and their main morphometric features were quantified. No young individuals were found, only large adults, whose survival could ensure population subsistence in more suitable environmental conditions. The present study provides evidence of a massive die-off affecting invasive bivalves during an extreme climatic event, producing decaying biomass with negative impacts on the water quality of the lake. Further investigations of the population dynamics of this species and the environmental quality of the water body are needed to develop an appropriate management plan in relation to the ecosystem services it delivers.