New Zealand mud snail
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209814895
2008-05-03T00:50:52Z
Squids and Chips
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Disambiguate [[Operculum]] to [[Operculum (gastropod)]] using [[:en:Wikipedia:Tools/Navigation_popups|popups]]
{{Otheruses4|the invasive mud snail ''Potamopyrgus antipodarum''|another mud snail from New Zealand|Amphibola crenata}}
{{Taxobox
| name = New Zealand mud snail
| image = P_antipodarum.jpg
| image_width = 214px
| status = NE
| regnum = [[Animal]]ia
| phylum = [[Mollusc]]a
| classis = [[Gastropod]]a
| ordo = [[Sorbeoconcha]]
| familia = [[Hydrobiidae]]
| genus = ''[[Potamopyrgus]]''
| species = '''''P. antipodarum'''''
| binomial = ''Potamopyrgus antipodarum''
| binomial_authority = [[John Edward Gray|J. E. Gray]], 1843
}}
The '''New Zealand mud snail''', ''Potamopyrgus antipodarum'', sometimes previously known as ''Potamopyrgus jenkinsii'', is a very small or minute [[species]] of freshwater [[snail]] with an [[Operculum (gastropod)|operculum]], an aquatic [[gastropod]] [[mollusk]] in the [[family (biology)|family]] [[Hydrobiidae]].
This is an [[invasive species]] in many countries, where populations of this snail can reach phenomenal densities.
==Distribution==
This species is [[endemism|endemic]] to [[New Zealand]], but it has spread widely and has become an invasive species in [[Australia]], [[Europe]], and [[North America]].
==Shell description==
This is an [[operculum (gastropod)|operculate]] snail, meaning it has a 'lid' that can seal the opening of its shell.
The shell can be either gray or brown in colour, and typically has five to eight [[whorl (mollusc)|whorls]] coiling out in a clockwise ('right handed' or dextral) direction.
The shell can be up to 12 [[millimetre|mm]] (<math>\begin{matrix} \frac{1}{2} \end{matrix}</math> in) long but the average size is 5 mm (<math>\begin{matrix} \frac{1}{5} \end{matrix}</math> in).<ref name="Benson1">{{cite web | author=Benson, Amy| year=2006 | title=Potamopyrgus antipodarum | work=USGS Nonindigenous Aquatic Species Database | url=http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1008 | accessdate=2006-05-04}}</ref>
==Life habits==
===Food sources===
Mud snails feed on [[Decomposition|decomposing]] animal and plant matter, [[bacteria]], and [[algae]].
===Reproduction===
They can reproduce [[Asexual reproduction|asexually]]; females "are born with developing embryos in their reproductive system."<ref name="Benson1" /> Each female can produce between 20 and 120 [[embryo]]s.<ref name="Montana">{{cite web | title=Biology | work=New Zealand mudsnails in the Western USA | publisher=Montana State University | url=http://www.esg.montana.edu/aim/mollusca/nzms/biology.html | accessdate=2006-05-04}}</ref>
In their native habitat, the snails pose no problem because of a [[Trematoda|trematode]] parasite which sterilizes many snails, keeping the populations to a manageable size. However they have become an invasive pest species elsewhere in the world in the absence of these parasites.
The parasites of this species include at least 11 species of Trematoda<ref>[http://www.indiana.edu/~curtweb/trematodes/Winterbourne.htm Larval Trematoda: Winterbourne<!-- Bot generated title -->]</ref>
* ''[[Microphallus]]'' sp.<ref>[http://www.indiana.edu/~curtweb/Research/About%20Microphallus.html About Microphallus<!-- Bot generated title -->]</ref>
The rapid reproduction rate of the snail has led to it accumulating quickly in new environments. The highest concentration of New Zealand mud snails ever reported was in [[Lake Zurich]], [[Switzerland]], where the species colonized the entire lake within seven years to a density of 800,000 per m².<ref>
{{cite web | year=2006| title=New Zealand mudsnail (Potamopyrgus antipodarum) | work=Kansas Department of Wildlife and Parks | url=http://www.kdwp.state.ks.us/news/fishing/aquatic_nuisance_species/aquatic_nuisance_species_list/new_zealand_mudsnail
| accessdate=2006-05-04}}
</ref>
==An invasive species==
While [[endemic (ecology)|endemic]] to New Zealand, the New Zealand mud snail has become [[Naturalisation (biology)|naturalised]] in Australia, Europe ([[List of molluscs recorded in Germany|Germany]], [[List of molluscs recorded in Poland|Poland]], [[List of molluscs recorded in the Czech Republic|Czech Republic]], [[List of molluscs recorded in Slovakia|Slovakia]]<ref>Čejka T., Dvořák L. & Košel V. 2008: [http://mollusca.sav.sk/pdf/7/7.Cejka.pdf Present distribution of ''Potamopyrgus antipodarum'' (Gray, 1843) (Mollusca: Gastropoda) in the Slovak Republic]. - Malacologica Bohemoslovaca, 7: 21-25. Online serial at <http://mollusca.sav.sk> 25-February-2008.</ref> and others), and North America, most likely due to inadvertent human intervention.
==History within the USA==
First detected in the [[United States]] in [[Idaho]]'s [[Snake River]] in [[1987]], the mud snail has since spread to the [[Madison River]], [[Firehole River]], and other watercourses around [[Yellowstone National Park]]; samples have been discovered throughout the Western United States.<ref name="Benson1" /> Although the exact means of transmission is unknown, it is likely that it was introduced in water transferred with live [[game fish]] and has been spread by [[ship ballast]] or contaminated recreational equipment such as wading gear.<ref name="Montana" />
The New Zealand mud snail has no natural predators or parasites in the United States, and consequently has become an [[invasive species]]. It can reach concentrations above 500,000 per m², endangering the [[food chain]] by outcompeting native snails and water insects for food, leading to sharp declines in the native populations.<ref>{{cite web | author=Benson, Amy| year=2006| title=New Zealand Mudsnail: Potamopyrgus antipodarum | work=Florida Integrated Science Center | url=http://cars.er.usgs.gov/Nonindigenous_Species/New_Zealand_Mudsnail/new_zealand_mudsnail.html | accessdate=2006-05-04}}</ref> Fish populations then suffer because the native snails and insects are their main food source.
The mud snails are impressively resilient. A snail can live for 24 hours without water. They can however survive for up to 50 days on a damp surface,<ref name="research summary">{{cite web|last=Davis |first=Ken W. | date=[[2004-02-24]] |url=http://www.wildlifefiles.com/pdfs/NZMS%20Research%20Findings%2022304.pdf |title=Select Research Findings on the New Zealand Mudsnail (''Potamopyrgus antipodarum'') |format=PDF |pages=1 |publisher=Wildlife Survey & Photo Service |accessdate=2006-05-07 }}</ref> giving them ample time to be transferred from one body of water to another on fishing gear. The snails may even survive passing through the digestive system of a fish.
[[Image:Mudsnail2.jpg|thumb|left|Mud snail size compared to an [[Dime (United States coin)|American dime]].]]
Mud snails have now spread from Idaho to most western states of the U.S., including [[Wyoming]], [[California]], [[Oregon]], and [[Montana]]. Environmental officials for these states have attempted to slow the spread of the snail by advising the public to keep an eye out for the snails, and bleach or heat any gear which may contain the mud snails. Rivers have also been temporarily closed to fishing to avoid anglers spreading the snails.<ref name="Putah Creek">{{cite web | title=News Release - Discovery of Invasive New Zealand Mud Snail Forces Temporary Closure of Putah Creek | publisher=California Department of Fish and Game | url=http://www.dfg.ca.gov/news/news03/03119.html | date=[[2003-12-16]] | accessdate=2006-05-07}}</ref>
The snails grow to a smaller size in the U.S. than in their native habitat, reaching 6 mm (<math>\begin{matrix} \frac{1}{4} \end{matrix}</math> in) at most in parts of Idaho, but can be much smaller making them easy to overlook when cleaning fishing gear.
Clonal species like the New Zealand mud snail can often develop clonal lines with quite diverse appearances, called [[Morph (zoology)|morph]]s. Until 2005, all the snails found in the western states of the U.S. were believed to be from a single line. However a second morph has been identified in Idaho's Snake River. It grows to a similar size but has a distinctive appearance. (It has been nicknamed the salt-and-pepper mud snail due to the face and final whorl being lighter than the rest of the shell.) This morph has apparently been present in the area for several years before being identified correctly as a distinct morph of ''Potamopyrgus antipodarum''. It dominates the typical morph where they overlap, and has a much higher prevalence of males.<ref name="second morph">{{cite web | title=Western USA ''Potamopyrgus antipodarum'' morphs | publisher=Department of Ecology, Montana State University-Bozeman | url=http://www.esg.montana.edu/aim/mollusca/nzms/morphs.html | date=[[2006-02-22]] | accessdate=2006-05-07}}</ref>
In [[1991]] the New Zealand mud snail was discovered in [[Lake Ontario]] in the [[Great Lakes]], and by [[2006]] had spread to [[Twin Ports|Duluth-Superior]] Harbour and the freshwater estuary of the [[Saint Louis River]].<ref>{{cite news | title=Invasive snail found in Minn. harbor | date=May 3, 2006 | publisher=Associated Press | url=http://seattlepi.nwsource.com/national/1501AP_Invasive_Species_Snail.html}}</ref> The snails in the Great Lakes represent a different line from those found in western states, and were probably introduced indirectly through Europe.<ref name="second morph"/>
==See also==
* ''[[Tryonia]]''
==References==
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==External links==
* Pesticides Database - Chemical Toxicity Studies - [http://www.pesticideinfo.org/List_AquireAll.jsp?Species=5642&Effect=], [http://www.pesticideinfo.org/List_AquireAll.jsp?Species=2442&Effect=]
[[Category:Hydrobiidae]]
[[Category:Molluscs of New Zealand]]
[[Category:Invasive animal species]]
[[cs:Písečník novozélandský]]