Invasion
Invasion Description
1st established record:Essex/England/North Sea estuaries (1887, Eno 1996; Eno et al. 1996; Eno et al. 1997)
1st record: Liverpool/England/Liverpool Bay, Irish Sea (1872, Blanchard 1997, failed)
Geographic Extent
Northern Ireland/Belfast Lough, Irish Sea (2007, Minchin 2007, 1 specimen on boat; 2009, established populations, McNeill et al. 2010); Wales/Menai Strait (2008, Bohn et al. 2015, eradicated); Liverpool/England/Liverpool Bay, Irish Sea (1872, Blanchard 1997, failed); Cleethorpes, Lincolnshire/England/North Sea (1893, Blanchard 1997); Essex/England/North Sea estuaries (1887, Eno 1996; Eno et al. 1996; Eno et al. 1997); Essex/England/Blackwater River (Chipperfield 1951); Brightlingsea, Essex/England/Colne Estuary (1893, Blanchard 1997); England/Thames Estuary (1893, Blanchard 1997); England/eastern English Channel (Hinz et al. 2011, increased abundance in surveys from 1958-1959, to 2006); Bosham, West Sussex/England/oyster ponds, the Solent (1913, Blanchard 1997); Ostende/Belgium/North Sea (1911, Blanchard 1997); Hermanville, Normandy/France/English Channel (1949, Goulletquer et al. 2002); Berren asn Zee/Netherlands/North Sea (1922, Blanchard 1997); Zandvoort/Netherlands/North Sea (1922, Blanchard 1997); Netherlands/Scheldt Estuary (1929, Blanchard 1997); Netherlands/Lake Grevelingen (Blanchard 1997); northern Frisen/Germany/Wadden Sea (1948, Blanchard 1997; Buschbaum et al. 2012); Germany/Elbe estuary (poly-euhaline, Nehring 2006); Isle of Sylt/Germany/Wadden Sea (1932, Blanchard 1997); Denmark/Nissum Bredning, Limfjord (1932, Blanchard 1997; Jensen and Knudsen 2005); Denmark/North Sea (1932-2018 Jensen et al. 2023)
Vectors
| Level | Vector |
|---|---|
| Probable | Oyster Accidental |
Regional Impacts
| Ecological Impact | Competition | |
| In British waters, Crepidula fornicata is considered to compete with bivalves for phytoplankton and space (Eno et al. 1997). However, experiments comparing diets of C. fornicata and Pacific Oysters (Crassostrea gigas, or effects of attached Crepidula on oyster growth give variable results (de Montaudouin et al. 1999; Thieltges et al. 2006; Decottignies et al. 2007a; Decottignies et al. 2007b). Thieltges (2005) found that attached stacks of C. fornicata resulted in reduced growth and survival of Blue Mussels (Mytilus edulis. Since a similar effect occurred with attached 'fake limpets', the effect did not appear to the result of trophic competition. Instead, increased hydrodynamic stress caused the mussels to invest more energy in byssus production, reducing energy available for growth, which could be considered a form of interference competition (Thieltges 2005; Thiletges and Buschbaum 2007). Crepidula fornicata colonies compete for space with the commecially important Great Scallop (Pecten maximus), reducing the area vailable for settlement of larval scallops (Ménesguen and Grégoris 2018). | ||
| Ecological Impact | Habitat Change | |
| In British waters, Crepidula fornicata is considered to alter habitats by deposition of large quantities of feces and pseudofeces, increasing the depth and extent of mud (Eno et al. 1997; Thieltges et al. 2003). In addition, the stacks of shells increase deposition by slowing water currents (Blanchard 1997; Thieltges et al. 2003). In the German Wadden Sea, C. fornicata is moving into mussel (Mytilus edulis beds, and now constitutes a major part of the biota there ( Thieltges et al. 2003; Thieltges et al. 2004). Crepidula fornicata colonies compete for space with the commecially important Great Scallop (Pecten maximus), reducing the area vailable for settlement of larval scallops (Ménesguen and Grégoris 2018). | ||
| Economic Impact | Fisheries | |
| Dense limpet populations impede oyster and mussel culture and other fisheries, in the Thames, Scheldt and Wadden sea (Belgium-Netherlands-Germany) estuaries and require extensive cleaning of catches to remove the attached snails (Blanchard 1997; Thieltges et al. 2003). Crepidula fornicata colonies compete for space with the commecially important Great Scallop (Pecten maximus), reducing the area available for settlement of larval scallops. Modeling indicates that abundance and area of Crepdula colonies affects callop landings in the the bay of Saint-Brieuc, France (Ménesguen and Grégoris 2018). | ||
| Ecological Impact | Herbivory | |
| Crepidula fornicata has developed large biomasses, which have the potential to lower phytoplankton biomass, through filter-feeding (Eno et al. 1997). However, feeding rates in the North Sea, English Channel, and Irish Sea regions, have not been quantified to our knowledge. | ||