Crepidula fornicata Linnaeus, 1758

C. fornicata stacks, when numerous in densely colonized areas, prevent other larvae and juveniles from settling and spatial competition occurs. Most species shift into other areas but many other of epifaunal species decrease in number or disappear because of available ground surfaces (Blanchard, 2009). For the flat fish Solea solea, Le Pape and al. (2004) demonstrated that the spatial competition which occurs between the fish and the C. fornicata favours the latter. (CABI, acesso em 21/06/202) (Pape et al., 2004);

Today, at least seven extensive (several km2 ) maerl grounds have been extracted, buried or affected by the spread of Crepidula fornicata. Such declines in one of the most diverse habitats of European waters (BIOMAERL, 1999) have not previously been reported and emphasize the urgent need for maerl bed conservation in France and Europe.

Crepidula fornicata is one of many reasons for the decline in local maerl bed habitats in Britain. Live maerl thalli become covered in Crepidula and the interstices of the deposit become clogged with silt; this kills the maerl thalli and dramatically alters associated maerl communities. Today, at least seven extensive (several km2 ) maerl grounds have been extracted, buried or affected by the spread of Crepidula fornicata. Such declines in one of the most diverse habitats of European waters (BIOMAERL, 1999) have not previously been reported and emphasize the urgent need for maerl bed conservation in France and Europe. (Grall and Hall-Spencer, 2003)