Invasion HistoryFirst Non-native North American Tidal Record: 1972
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1972
General Invasion History:
Sphaerium corneum is a small deposit-feeding freshwater bivalve native to Eurasia (Herrington 1962; Kuiper et al. 1989). Published records range from France, the British Isles, Sweden and Finland to Poland and Lithuania (Kuiper et al.1989), including low-salinity regions of the Baltic Sea (Remane and Schleiper 1971; Zettler and Daunys 2007). It has been introduced to the Great Lakes, the Saint Lawrence River and Estuary, Lake Champlain, Lake George, and the Hudson River (Strayer 1987; Letarte and Vaillancourt 1988; Mills et al. 1993; Marsden 2009; USGS Nonindigenous Aquatic Species Program 2012).
North American Invasion History:
Invasion History on the East Coast:
Sphaerium corneum was first recorded in North America in 1924 in Lake Ontario (Duggan et al. 2003). Possible vectors of introduction include dry ballast and marsh grasses used as packing materials for fragile European goods. It is now found through the Great Lakes-St. Lawrence system, from Lake Superior (Grigorovich et al. 2003) to Lakes Erie and Ontario (Herrington 1962) and the upper St. Lawrence Estuary. In the St. Lawrence estuary, it ranges from the Lac St. Pierre Dam at the head of tide to Quebec City (Vincent 1979; LeTarte and Vaillancourt 1988).
Sphaerium corneum was reported from the Hudson River, near Albany, New York in 1972 by Simpson (1976, cited by Strayer 1987). Strayer found one shell near Kingston in 1987, but considered that the presence of this clam required confirmation, given difficulties of identification (Strayer 1987; Mills et al. 1993). This clam was found in Lake George, in the upper Hudson basin, in 2007 (USGS Nonindigenous Aquatic Species Program 2012).
Sphaerium corneum is a member of the family Pisidiidae (Pea Clams), which are minute freshwater clams, ranging from 1 to 25 mm in length. In the genus Sphaerium, the beak is at about the midpoint of the shell and two siphons, an oral and branchial siphon, are fully developed. The shell is thin, somewhat inflated, and looks like a compressed sphere in a view from the ends (Martin 1998). In S. corneum, the shell is oval, with a height of 0.74 - 0.81 of the length. Herrington's North American specimens ranged up to 8.6 mm in length, but he noted that European specimens were often larger, up to 13.5 mm (Herrington 1962). The beak is low, broad, and slightly anterior to the midpoint. The anterior dorsal edge is slightly curved, while the posterior end slopes more steeply, and is more strongly curved. The shell is covered with evenly spaced growth lines which become faint toward the beak. The hinge plate is rather long. The narrow and curved 3rd cardinal is parallel to the hinge plate, expanded, and often bifurcated posteriorly. The narrow 4th and 2nd cardinal teeth are very close to parallel and the former overlaps the latter. The shell is brown to gray (Herrington 1962; Clarke 1981).
Potentially Misidentified Species
This clam has a Holarctic distribution (Herrington 1962).
Sphaerium corneum is a small deposit-feeding freshwater clam, which burrows in the sediment of rivers, streams, and lakes. Fingernail clams are hermaphroditic and oviviparous, 'giving birth' to shelled juveniles (Martin 1998). In the St. Lawrence River, S. corneum started carrying embryos at 4.0 mm in size. The numbers of embryos increased with body size, but varied temporally, from 4 embryos for a 9 mm clam in August 1983 to highs of 9-10 for a same-sized clam in November 1983 and June 1984. The highest fecundity seen was 13 embryos (Letarte and Vaillancourt 1988). Annual fecundity is estimated at 63 embyos per female (Keller et al. 2007).
Sphaerium corneum is a freshwater species, but occurs at salinities of at least 3 PSU (Remane and Schleiper 1971; Zettler and Daunys 2007). Fingernail Clams feed by filtering detritus and particles in interstitial waters (Thorp and Covich 2001). As a group, fingernail clams are an important food for benthic invertebrates and fishes (Martin 1998).
Detritus, benthic diatoms
|General Habitat||Unstructured Bottom||None|
|Salinity Range||Limnetic||0-0.5 PSU|
|Salinity Range||Oligohaline||0.5-5 PSU|
Tolerances and Life History Parameters
|Minimum Salinity (‰)||0||This is a freshwater species.|
|Maximum Salinity (‰)||3||Field, Baltic Sea, Remane and Schlieper 1971|
|Minimum Length (mm)||4||Minimum reproductive size, St. Lawrence River (Letarte and Vaillancourt 1988).|
|Maximum Length (mm)||13.5||European specimens, cited by Herrington (1962). Clams from the St. Lawrence River reached 10 mm (Letarte and Vaillancourt 1988).|
|Broad Temperature Range||None||Cold temperate|
|Broad Salinity Range||None||Nontldal Limnetic-Oligohaline|
General ImpactsSphaerium corneum is common in the St. Lawrence River Estuary and widespread in the Great Lakes (Herrington 1962; Letarte and Vaillancourt 1988). However, no ecological or economic impacts have been reported for this species.
Regional Distribution Map
|Bioregion||Region Name||Year||Invasion Status||Population Status|
|M060||Hudson River/Raritan Bay||1972||Def||Unk|
|GL-I||Lakes Huron, Superior and Michigan||2001||Def||Estab|
|L013||_CDA_L013 (St. Louis River)||2001||Def||Estab|
|L018||_CDA_L018 (Portage River)||2001||Def||Estab|
|L061||_CDA_L061 (St. Marys)||2001||Def||Estab|
References2002-2016a Malacology Collection Search. http://clade.ansp.org/malacology/collections/
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Duggan, Ian C.; Bailey, Sarah A.; Colauttii, Robert I.; Gray, Derek K.; Makarewicz; Joseph C.; Hugh J. MacIsaac (2003) State of Lake Ontario (SOLO): Past, Present and Future, Aquatic Ecosystem Health and Management Society, Burlington, Ontario. Pp. 1-17
Grigorovich, Igor A; Korniushin, Alexei V.; Gray, Derek K.; Duggan, Ian C.; Colautti, Robert I.; MacIsaac, Hugh J. (2003) Lake Superior: an invasion coldspot?, Hydrobiologia 499: 191-210
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