New Zealand Mud Snail
Encyclopedia
The New Zealand mudsnail, Potamopyrgus antipodarum, sometimes previously known as Potamopyrgus jenkinsi, is a species
of very small or minute freshwater snail
with a gill
and an operculum
, an aquatic gastropod mollusk in the family
Hydrobiidae
.
This is an invasive species
in many countries, where populations of this snail can reach phenomenal densities.
The shell
of Potamopyrgus antipodarum is elongated and it has dextral coiling. The shell has 7 or 8 whorls
. Between whorls are deep grooves.
This is an operculate
snail, meaning it has a 'lid' that can seal the opening of its shell. The operculum
is thin and corneus with an off-centre nucleus from which paucispiral markings (with few coils) radiate. The aperture
is oval and its height is less than the height of the spire
.
Some morphs, including many from the Great Lakes, exhibit a keel in the middle of each whorl; others, excluding those from the Great Lakes, exhibit periostracal
ornamentation such as spines for anti–predator defense.
Shell colors vary from gray and dark brown to light brown.
The average height of the shell is approximately 5 mm (
in); maximum size is approximately 12 mm (
in). The snail is usually 4–6 mm in length in the Great Lakes
, but grows to 12 mm in its native range.
:
"Inhabits New Zealand, in fresh water. Shell ovate, acute, subperforated (generally covered with a brown earthy coat); whorls rather rounded, mouth ovate, axis 3 lines; operculum horny and subspiral: variety, spire rather longer, whorls more rounded. This species is like Paludina nigra of Quoy and Gaimard, but the operculum is more spiral. Quoy described the operculum as concentric, but figured it subspiral. Paludina ventricosa of Quoy is evidently a Nematura."
. It lives in freshwater streams and lakes in New Zealand and adjacent small islands.
to New Zealand, the New Zealand mud snail has spread widely and has become naturalised
and an invasive species
in many areas including: Australia, Tasmania, Asia (Japan, in Garmat Ali River in Iraq since 2008), Europe (since 1859 in England), and North America (USA and Canada: Thunder Bay in Ontario since 2001, British Columbia since July 2007), most likely due to inadvertent human intervention.
Potamopyrgus antipodarum occurs in nearly the whole of Europe. It does not occur in Iceland, Albania, Bulgaria and the former Yugoslavia.
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. 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.
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. 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, 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.
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.
The snails grow to a smaller size in the U.S. than in their native habitat, reaching 6 mm (¼ 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 morphs. 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 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.
In 1991 the New Zealand mud snail was discovered in Lake Ontario
, and has now been found in four of the five Great Lakes
. In 2005 and 2006, it was found to be widespread in Lake Erie. By 2006 it had spread to Duluth-Superior
Harbour and the freshwater estuary of the Saint Louis River
. It was found to be inhabiting Lake Michigan
, after scientists took water samples
in early summer of 2008. The snails in the Great Lakes represent a different line from those found in western states, and were probably introduced indirectly through Europe.
Olympia Washington's Capital Lake is infested with the New Zealand Mud Snail. All three Boat Launches at the lake have been temporarily closed to pleasure boat traffic by the State's Department of General Administration.
In 2010, the Los Angeles Times
reported that the New Zealand mud snail had infested watersheds in the Santa Monica Mountains
, posing serious threats to native species and complicating efforts to improve stream-water quality for the endangered steelhead trout. According to the article, the snails have expanded "from the first confirmed sample in Medea Creek in Agoura Hills to nearly 30 other stream sites in four years." Researchers at the Santa Monica Bay Restoration Commission believe that the snails' expansion may have been expedited after the mollusks traveled from stream to stream on the gear of contractors and volunteers.
In Colorado, Boulder Creek and Dry Creek have infestations of New Zealand Mud Snails. The snails have been present in Boulder Creek since 2004 and were discovered in Dry Creek in Sept. 2010. Access to both creeks has been closed to help avoid spread of the snails.
, thrives in disturbed watersheds, and benefits from high nutrient flows allowing for filamentous green algae growth. It occurs amongst macrophytes and prefers littoral
zones in lakes or slow streams with silt and organic matter substrates, but tolerates high flow environments where it can burrow into the sediment.
In the Great Lakes, the snail reaches densities as high as 5,600 m2 and is found at depths of 4–45 m on a silt and sand substrate.
This species is euryhaline
, establishing populations in fresh and brackish water
. The optimal salinity
is probably near or below 5 ppt
, but Potamopyrgus antipodarum is capable of feeding, growing, and reproducing at salinities of 0–15 ppt and can tolerate 30–35 ppt for short periods of time.
It tolerates temperatures of 0–34°C.
, epiphytic and periphytic algae
, sediments and diatom
s.
; females "are born with developing embryos in their reproductive system."
Native populations in New Zealand consist of diploid sexual and triploid parthenogenically cloned females, as well as sexually functional males (less than 5% of the total population). All introduced populations in North America are clonal, consisting of genetically identical females.
Each female can produce between 20 and 120 embryo
s. The snail produces approximately 230 young per year. Reproduction occurs in spring and summer, and the life cycle is annual.
The rapid reproduction rate of the snail has caused the numbers of individuals to increase rapidly 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.
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.
Common parasites of this snail include trematodes of the genus Microphallus
.
of fish and birds and may be transported by these animals.
It can also float by itself or on mats of Cladophora
spp., and move 60 m upstream in 3 months through positive rheotactic behavior. It can respond to chemical stimuli in the water, including the odor of predatory fish, which causes it to migrate to the undersides of rocks to avoid predation.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of very small or minute freshwater snail
Freshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....
with a gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
and an operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
, an aquatic gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Hydrobiidae
Hydrobiidae
Hydrobiidae, common name mud snails, is a large cosmopolitan taxonomic family of very small freshwater snails and brackish water snails that have an operculum, aquatic gastropod mollusks in the clade Littorinimorpha.- Distribution :...
.
This is an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in many countries, where populations of this snail can reach phenomenal densities.
Shell description
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
of Potamopyrgus antipodarum is elongated and it has dextral coiling. The shell has 7 or 8 whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
. Between whorls are deep grooves.
This is an operculate
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
snail, meaning it has a 'lid' that can seal the opening of its shell. The operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
is thin and corneus with an off-centre nucleus from which paucispiral markings (with few coils) radiate. The aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is oval and its height is less than the height of the spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
.
Some morphs, including many from the Great Lakes, exhibit a keel in the middle of each whorl; others, excluding those from the Great Lakes, exhibit periostracal
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
ornamentation such as spines for anti–predator defense.
Shell colors vary from gray and dark brown to light brown.
The average height of the shell is approximately 5 mm (
in); maximum size is approximately 12 mm ( in). The snail is usually 4–6 mm in length in the Great LakesGreat Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
, but grows to 12 mm in its native range.
Original description
This species was originally described as Amnicola antipodarum in 1843 by John Edward GrayJohn Edward Gray
John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
:
"Inhabits New Zealand, in fresh water. Shell ovate, acute, subperforated (generally covered with a brown earthy coat); whorls rather rounded, mouth ovate, axis 3 lines; operculum horny and subspiral: variety, spire rather longer, whorls more rounded. This species is like Paludina nigra of Quoy and Gaimard, but the operculum is more spiral. Quoy described the operculum as concentric, but figured it subspiral. Paludina ventricosa of Quoy is evidently a Nematura."
Distribution
This species is endemic to New ZealandNew Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. It lives in freshwater streams and lakes in New Zealand and adjacent small islands.
Nonindigenous distribution
While endemicEndemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to New Zealand, the New Zealand mud snail has spread widely and has become naturalised
Naturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
and an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in many areas including: Australia, Tasmania, Asia (Japan, in Garmat Ali River in Iraq since 2008), Europe (since 1859 in England), and North America (USA and Canada: Thunder Bay in Ontario since 2001, British Columbia since July 2007), most likely due to inadvertent human intervention.
Invasion in Europe
- England since 1859 - probably the first introduction in Europe
- Germany
- Poland
- Western Baltic Sea since 1887
- Russia
- Azov Black SeaBlack SeaThe Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
region, since 1951, Ukraine since 1951 in brackish waters, and since 2005 in freshwater - Catalonia in Spain, since 1952
- Mediterranean region of France, since the end of 1950s
- Italy, since 1961
- Turkey
- Czech Republic, since September 3, 1981
- Slovakia, since 1986
- Greece, since November 2007
- and other areas
Potamopyrgus antipodarum occurs in nearly the whole of Europe. It does not occur in Iceland, Albania, Bulgaria and the former Yugoslavia.
Distribution within the USA
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
's Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...
in 1987, the mud snail has since spread to the Madison River
Madison River
The Madison River is a headwater tributary of the Missouri River, approximately 183 miles long, in Wyoming and Montana. Its confluence with the Jefferson and Gallatin rivers near Three Forks, Montana form the Missouri River....
, Firehole River
Firehole River
The Firehole River is one of two major tributaries of the Madison River. It flows north approximately from its source in Madison Lake on the Continental Divide to join the Gibbon River at Madison Junction in Yellowstone National Park...
, and other watercourses around Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...
; samples have been discovered throughout the Western United States. Although the exact means of transmission is unknown, it is likely that it was introduced in water transferred with live game fish
Game fish
Game fish are fish pursued for sport by recreational anglers. They can be freshwater or marine fish. Game fish can be eaten after being caught, though increasingly anglers practise catch and release to improve fish populations. Some game fish are also targeted commercially, particularly...
and has been spread by ship ballast or contaminated recreational equipment such as wading gear.
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
Food chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
by outcompeting native snails and water insects for food, leading to sharp declines in the native populations. 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, 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.
Mud snails have now spread from Idaho to most western states of the U.S., including Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, and Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
. 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.
The snails grow to a smaller size in the U.S. than in their native habitat, reaching 6 mm (¼ 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 morphs. 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 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.
In 1991 the New Zealand mud snail was discovered in Lake Ontario
Lake Ontario
Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...
, and has now been found in four of the five Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
. In 2005 and 2006, it was found to be widespread in Lake Erie. By 2006 it had spread to Duluth-Superior
Twin Ports
The Twin Ports of Duluth, Minnesota and Superior, Wisconsin are located at the western part of Lake Superior and together are considered the largest freshwater port in the world. They are twin cities and seaports, connected to the Atlantic Ocean through the Great Lakes and the St. Lawrence...
Harbour and the freshwater estuary of the Saint Louis River
Saint Louis River
The St. Louis River is a river in the U.S. states of Minnesota and Wisconsin that flows into Lake Superior. The largest U.S. river to flow into the lake, it is 179 miles in length and starts near Hoyt Lakes, Minnesota. The river's watershed is in area...
. It was found to be inhabiting Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
, after scientists took water samples
Sample (material)
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, or a material not countable as individual items. Samples of countable...
in early summer of 2008. The snails in the Great Lakes represent a different line from those found in western states, and were probably introduced indirectly through Europe.
Olympia Washington's Capital Lake is infested with the New Zealand Mud Snail. All three Boat Launches at the lake have been temporarily closed to pleasure boat traffic by the State's Department of General Administration.
In 2010, the Los Angeles Times
Los Angeles Times
The Los Angeles Times is a daily newspaper published in Los Angeles, California, since 1881. It was the second-largest metropolitan newspaper in circulation in the United States in 2008 and the fourth most widely distributed newspaper in the country....
reported that the New Zealand mud snail had infested watersheds in the Santa Monica Mountains
Santa Monica Mountains
The Santa Monica Mountains are a Transverse Range in Southern California, along the coast of the Pacific Ocean in the United States.-Geography:...
, posing serious threats to native species and complicating efforts to improve stream-water quality for the endangered steelhead trout. According to the article, the snails have expanded "from the first confirmed sample in Medea Creek in Agoura Hills to nearly 30 other stream sites in four years." Researchers at the Santa Monica Bay Restoration Commission believe that the snails' expansion may have been expedited after the mollusks traveled from stream to stream on the gear of contractors and volunteers.
In Colorado, Boulder Creek and Dry Creek have infestations of New Zealand Mud Snails. The snails have been present in Boulder Creek since 2004 and were discovered in Dry Creek in Sept. 2010. Access to both creeks has been closed to help avoid spread of the snails.
Habitat
The snail tolerates siltationSiltation
Siltation is the pollution of water by fine particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments, and to the increased accumulation of fine sediments on bottoms where they are undesirable...
, thrives in disturbed watersheds, and benefits from high nutrient flows allowing for filamentous green algae growth. It occurs amongst macrophytes and prefers littoral
Littoral
The littoral zone is that part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to...
zones in lakes or slow streams with silt and organic matter substrates, but tolerates high flow environments where it can burrow into the sediment.
In the Great Lakes, the snail reaches densities as high as 5,600 m2 and is found at depths of 4–45 m on a silt and sand substrate.
This species is euryhaline
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly which can live in fresh, brackish, or salt water. The European shore crab is an example of a euryhaline invertebrate that can live in salt and brackish water...
, establishing populations in fresh and brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
. The optimal salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
is probably near or below 5 ppt
PPT
- Organizations :* Parti progressiste tchadien, a political party active in Chad between 1947 and 1973* Patria Para Todos, a left-wing political party in Venezuela* Permanent Peoples' Tribunal, an international opinion tribunal founded in Bologna, 1979...
, but Potamopyrgus antipodarum is capable of feeding, growing, and reproducing at salinities of 0–15 ppt and can tolerate 30–35 ppt for short periods of time.
It tolerates temperatures of 0–34°C.
Feeding habits
Potamopyrgus antipodarum is a nocturnal grazer, feeding on plant and animal detritusDetritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
, epiphytic and periphytic algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, sediments and diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...
s.
Life cycle
Potamopyrgus antipodarum is ovoviviparous and parthenogenic. This means that they can reproduce asexuallyAsexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
; females "are born with developing embryos in their reproductive system."
Native populations in New Zealand consist of diploid sexual and triploid parthenogenically cloned females, as well as sexually functional males (less than 5% of the total population). All introduced populations in North America are clonal, consisting of genetically identical females.
Each female can produce between 20 and 120 embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s. The snail produces approximately 230 young per year. Reproduction occurs in spring and summer, and the life cycle is annual.
The rapid reproduction rate of the snail has caused the numbers of individuals to increase rapidly in new environments. The highest concentration of New Zealand mud snails ever reported was in Lake Zurich
Lake Zurich
Lake Zurich is a lake in Switzerland, extending southeast of the city of Zurich. It is also known as Lake Zürich and Lake of Zürich. It lies approximately at co-ordinates ....
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, where the species colonized the entire lake within seven years to a density of 800,000 per m².
Parasites
In their native habitat, the snails pose no problem because of a trematodeTrematoda
Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as "flukes".-Taxonomy and biodiversity:...
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.
Common parasites of this snail include trematodes of the genus Microphallus
Microphallus
Microphallus is a genus of parasitic trematodes in the family Microphallidae. The Greek name means "tiny penis".- Hosts :They are parasitic on a variety of molluscs, crustaceans, birds, and mammals, some species having complex life cycles involving more than one host.For example, Microphallus...
.
Other interspecific relationship
Potamopyrgus antipodarum can survive passage through the gutsGut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
of fish and birds and may be transported by these animals.
It can also float by itself or on mats of Cladophora
Cladophora
Cladophora is a genus of reticulated filamentous Ulvophyceae . The genus Cladophora contains many species that are very hard to tell apart and classify, mainly because of the great variation in their appearances, which is affected by habitat, age and environmental conditions...
spp., and move 60 m upstream in 3 months through positive rheotactic behavior. It can respond to chemical stimuli in the water, including the odor of predatory fish, which causes it to migrate to the undersides of rocks to avoid predation.
Further reading
- Kerans, B. L, M. F. Dybdahl, M. M. Gangloff and J. E. Jannot. 2005. Potamopyrgus antipodarum: distribution, density, and effects on native macroinvertebrate assemblages in the Greater Yellowstone ecosystem. Journal of the North American Benthological Society 24(1):123–138.
- Strzelec, M. 2005. Impact of the introduced Potamopyrgus antipodarum (Gastropods) on the snail fauna in post–industrial ponds in Poland. Biologia (Bratislava) 60(2):159–163.
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=
- CISR - New Zealand Mud Snail Center for Invasive Species Research, Summary of New Zealand Mud Snail
- Species Profile- New Zealand Mud Snail (Potamopyrgus antipodarum), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for New Zealand Mud Snail.