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).