Pisidium moitessierianum
Paladilhe, 1866
Common Name:
Pygmy peaclam
Synonyms and Other Names:
Moitessier’s pea/pill clam, pisidiid clam, P. (Neopisidium) moitessierianum
Identification:
This triangle- to trapezoid-shaped pea clam displays a relatively rounded, thick, and coarsely striated shell with a height to length ratio of 0.88–0.90. The somewhat flattened beaks barely protrude above the dorsal margin, which exhibits a fold or ridge that is parallel to the growth rings. The 3rd cardinal tooth inside the right valve is curved and thick at both ends, with a bifurcated posterior part. The 2nd cardinal in the left valve is triangular and the 4th cardinal is a thin plate-like structure that is somewhat curved. In live individuals, there is only one siphon (Grigorovich et al. 2000).
Size:
around 1.8 to 2.8 mm long (Grigorovich et al. 2000, Holopainen 1979).
Native Range:
Pisidium moitessierianum is native to eastern and western European countries as well as Asia in southwestern Siberia and northeastern Kazakhstan (Grigorovich et al. 2000).
Great Lakes Nonindigenous Occurrences:
Pisidium moitessierianum was observed for the first time in the Great Lakes basin in the Tuscarawas River, which is connected to the Ohio and Erie Canal, in the 1890s. It was originally identified as P. punctatum. It has also been recorded from Lake St. Clair, the St. Clair River delta, western Lake Erie, and Lake Superior, in 1997–2001 (Grigorovich et al. 2000, Grigorovich et al. 2003a, Korniushin et al. 2001).
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Pisidium moitessierianum are found here.
Full list of USGS occurrences
Table last updated 5/1/2024
† Populations may not be currently present.
Ecology:
Moitessier’s pea clam occurs in mud, silty sand, sand, silty gravel, and amongst macrophytes. It occurs from 0.5–20 m depth in the littoral zone of lakes and in wide slow rivers. It usually favors oligotrophic water with oxygen content over 50% saturation but it can tolerate some anoxic conditions over winter. Pisidium moitessierianum is relatively thermophilic, preferring lower river reaches, and has recently been able to colonize Lake Annecy, France, possibly due to increasingly warm lake water. It can, however, tolerate an annual water temperature range of 1–20ºC. Maximum population densities in the Great Lakes reach 145–178 individuals per m2 (Bishop and Hewitt 1976, Grigorovich et al. 2000, Grigorovich et al. 2003a, Holopainen and Hanski 1986, Mouthon 1999,Mouthon and Magny 2004, Smit et al. 1994, Zittler and Kuiper 2002). Pisidium moitessierianum is ovoviviparous, hermaphroditic, can undergo self-fertilization, and generally carries 1–10 embryos. In Lake Paajarvi, Finland, it becomes sexually mature around 1 year, lays eggs in August to September, broods its offspring, releases them in July around 2 years of age, and then dies (Grigorovich et al. 2000, Holopainen 1979).
Species in the genus Pisidium are interstitial feeders, creating burrows into which they draw water by using their cilia and foot. They feed on suspended material in the water column and also directly ingest deposits from the substrate in which they live (Lopez and Holopainen 1987).
Means of Introduction:
Pisidium moitessierianum was very likely introduced in ships to the Great Lakes sometime in the 1890s, most likely in solid ballast, which was in use at the time (Grigorovich et al. 2000; Grigorovich et al. 2003a; Grigorovich et al. 2003b).
Status:
Established where recorded.
Great Lakes Impacts:
Current research on the environmental impact of Pisidium moitessierianum in the Great Lakes is inadequate to support proper assessment.
Potential:
While the distribution of P. moitessierianum is thought to be patchy in parts of the Great Lakes, diffusing any significant ecological impact, it is apparently widespread in the Superior-Duluth Harbor (Grigorovich et al. 2000, Trebitz et al. 2010). It is known to coexist with other aquatic invertebrates, though its impact on other species and the ecosystem is unknown.
There is little or no evidence to support that Pisidium moitessierianum has significant socio-economic impacts in the Great Lakes.
This species does not appear to have any impacts on human health or recreation.
There is little or no evidence to support that Pisidium moitessierianum has significant beneficial effects in the Great Lakes.
This species does not appear to have any significant commercial or research value.
Management:
Regulations (pertaining to the Great Lakes region)
There are no known regulations for this species.
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
There are no known biological control methods for this species.
Physical
There are no known physical control methods for this species.
Research on drawdown as a potential control technology for P. moitessierianum suggests that it will be in-effective as a control in most situations (Mouthon 2011). Pisidiid clams showed poor resistance to a brief period of drying of the habitat, but also demonstrated high rates of recovery. In the study sites, drawdown did cause a decline in P. moitessierianum, but the population recovered quickly, becoming the dominant bivalve in the following year.
Chemical
A wide array of chemical molluscicides are available, but are not species-specific and may harm native species to a greater extent than non-natives.
Molluscicides are typically classified as either oxidizing or non-oxidizing compounds. Oxidizing chemicals include chlorine, chlorine dioxide, chloramines, ozone, bromine, hydrogen peroxide, and potassium permanganate. Non-oxidizing chemicals (including organic film-forming antifouling compounds, gill membrane toxins, and nonorganics) can be classified into several distinct groups: quanternary and polyquaternary ammonium compounds; aromatic hydrocarbons; endothall as the mono (N,N-dimethylalkyl amine) salt; metals and their salts (e.g., copper sulfate formulations); and niclosamide (including some formulations of Bayluscide). Bayluscide was initially developed as a sea lamprey larvicide, but has molluscicidal activity. While some of these products are biodegradable, many require detoxification or deactivation to meet state and Federal discharge requirements (USACE 2012).
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
Pisidium moitessierianum is considered rare in some parts of its native range (Beran and Horsak 1998, Dyduch and Falniowski 1979, Horsak 2001).
Pisidium moitessierianum is really P. (Neopisidium) moitessierianum, part of the polyphyletic subgenus Neopisidium (Kurniushin and Glaubrecht 2002).
References
(click for full reference list)
Author:
Kipp, R.M., J. Larson, and A. Fusaro
Contributing Agencies:
Revision Date:
11/26/2019
Citation for this information:
Kipp, R.M., J. Larson, and A. Fusaro, 2024, Pisidium moitessierianum Paladilhe, 1866: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatLakes/FactSheet.aspx?Species_ID=2375&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 11/26/2019, Access Date: 5/1/2024
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.