Gasterosteus aculeatus Linnaeus, 1758, a new host fish for the endangered Margaritifera auricularia (Spengler, 1793) (Unionoida: Margaritiferidae)

Abstract

The giant freshwater pearl mussel Margaritifera auricularia (Spengler, 1793) is considered the most imperilled bivalve species in Europe (Araujo & Ramos, 2001; Prié, 2010). Although likely widespread in most western European rivers at the beginning of the twentieth century, its decline in both abundance and distribution range has been estimated to be over 90% (Prié, 2010) and it is now nearly extinct. Only a few populations remain in Spain (Ebro Basin) and France (Loire, Charente, Garonne and Adour basins) (Araujo & Ramos, 2000a; Cochet, 2001; Prié et al., 2018; Soler et al., 2018...