Potamopyrgus antipodarum

Atlantic Europe, Baltic sea, Belgian Coast, Belgian Exclusive Economic Zone, Belt Sea, Elbe, Irish Exclusive economic Zone, Muuga harbour (Port of Tallinn, Gulf of Finland), New Zealand Exclusive Economic Zone, North Sea, Polish Exclusive Economic Zone, Portuguese Exclusive Economic Zone, Spanish Exclusive Economic Zone, Swedish Exclusive Economic Zone, United Kingdom Exclusive Economic Zone

New Zealand mudsnails (Potamopyrgus antipodarum) are native to freshwater streams and lakes of New Zealand and small, neighboring islands. However, by several speculated means of human introduction, they have become an invasive species in Australia, Europe, and North America. Occurrences of the species in North America, most of which are in the western United States, have been carefully documented since it was first discovered in Idaho. The snails are known to be established in Oregon, California, northern Arizona, New York, and Canada, affecting major freshwater systems such as Lake Ontario, Lake Erie, and Lake Superior. They also have been recently introduced in Japan.

Biogeographic Regions: nearctic (Introduced ); palearctic (Introduced ); australian (Introduced ); oceanic islands (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Native to New Zealand. Introduced to Europe in the 1800's where it is now widespread. Introduced into the Snake River system (Idaho) in North America (first appeared in 1987) and is now present in the Great Lakes and Madison and Missouri rivers (Howells 1999). Since spread to nearly a dozen sites in Lake Ontario (Zaranko et al., 1997). Kerans et al. (2005) list it from Idaho, Great Lakes, California, Wyoming, Montana. Recently introduced to Duluth-Superior Harbor in Duluth, Minnesota (MN DNR, 1 May 2006 news release).

New Zealand mudsnails are shelled organisms that are either gray in color or some shade of light to dark brown. Male and female New Zealand mudsnails are very similar in physical appearance, but females are distinguished from males by the presence of developing embryos in their reproductive systems. In the western United States, the average length of the shell of the New Zealand mudsnail is 4 to 5 mm, with a maximum length of 6 to 7 mm. In their native range, the maximum length of the shell is 12 mm. The surface of the shell is characterized by right-handed coiling of 5 to 6 whorls demarcated by sulci. The shells of some individuals have a keel in the middle of each whorl and/or spines for defense against predators. A terminal oval aperture covered by a thin operculum is also present. New Zealand mudsnails may resemble snails native to the United States, but they are distinguished by their longer, narrower shells that have a greater number of whorls.

Range length: 4 to 12 mm.

Sexual Dimorphism: sexes alike

Length: 1.2 cm

Shell dextral, solid, but not thick-walled. Aperture broadly elliptical with concave columellar margin. Peristome is complete across the parietal wall. The outer and basal lips thickened internally. Adult shell has seven to eight whorls. Length of spire greater than height of the aperture. Spire attenuate and concave in profile. First whorl is minute and raised while remaining whorls of spire evenly rounded between the deeply impressed suture. Body whorl bluntly angulate and slightly flattened abov e periphery, rounded occasionally. A raised periostracal spire line and frills may be present. Umbilicus narrowly perforate. Operculum ovate in shape, thin, corneas, and paucispiral; inner surface has a thin calcareous deposit (Zaranko et al., 1997).

New Zealand mudsnails prefer to live in streams and the littoral zones of lakes. They prefer shallow areas but can be found up to 60 m deep. They can be found in aquatic habitats of varying substrate types, including silt, sand, gravel, cobble, and macrophyte/vegetation. Densities are highest in macrophyte habitats and lowest in silt/sand habitats. Individuals of this species live in both eutrophic and clear waters, but they thrive in disturbed or degraded waters. New Zealand mudsnails can tolerate a wide range of temperatures, from near freezing to 34ºC. The optimal salinity of the water for the snails is near 5%, but they can tolerate brackish waters and even survive salinities as high as 30 to 35% for short periods of time. New Zealand mudsnails prefer low water velocities but can be found in high velocity areas buried in the sediment or underneath cobbles and boulders.

Range depth: 60 (high) m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams; brackish water

Other Habitat Features: intertidal or littoral

Depth range based on 94 specimens in 1 taxon.
Water temperature and chemistry ranges based on 40 samples.

Environmental ranges
  Depth range (m): 0 - 12.8
  Temperature range (°C): 7.165 - 7.165
  Nitrate (umol/L): 2.602 - 2.602
  Salinity (PPS): 6.151 - 6.151
  Oxygen (ml/l): 8.227 - 8.227
  Phosphate (umol/l): 0.286 - 0.286
  Silicate (umol/l): 9.489 - 9.489

Graphical representation

Depth range (m): 0 - 12.8
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Freshwater

Comments: Inhabits fresh and brackish water and has been found in water up to 26% aalinity (Zaranko et al., 1997). Lysne and Koetsier (2006) found this species had a preference for gravel substrates in the laboratory (attaining the greatest density) but utilizes almost any substrate. Holomuzki and Biggs (2006) found that most stream dwelling individuals are smooth-shelled while most lake dwelling individuals are spiny and also noted spiny forms are more prone to collect seston and become prone to flow-induced dislodgment than smooth morphs but have decreased predation pressure from the common bully (Gobiomorphus cotidianus).

The natural area of distribution of the New-Zealand mudsnail Potamopyrgus antipodarum is situated around New-Zealand, but around 1859 the species was introduced to Europe with barrels of drinking water. The little snails must have entered these barrels while they were beeing washed or refilled. In 1927 the first Belgian specimens of the snails were found in the river Scheldt around Antwerp. In Belgium the species inhabits fresh- to slightly brackish waters. This species can reproduce very fast, though parthenogenesis. These snails prey on young oysters, and are therefore not very popular among oyster farmers.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Well suited to passive dispersal by birds (Zaranko et al., 1997) and can pass through fish alimentary canal alive.

New Zealand mudsnails are considered scrapers/grazers. Their diet consists of diatoms, epiphytic and periphytic algae, and animal and plant detritus. Therefore, they can be considered planktivores, algivores, and detrivores.

Plant Foods: algae; phytoplankton

Other Foods: detritus

Primary Diet: herbivore (Algivore); planktivore ; detritivore

In their freshwater ecosystems, New Zealand mudsnails occupy the role of scrapers/grazers and are considered to be a link between primary producers and fish. They also play a vital role in the transmission of Microphallus to ducks by serving as intermediate hosts.

New Zealand mudsnails are known to exist in extremely high densities and may comprise more than 90% of the macroinvertebrate biomass in introduced habitats. Due to their abundance, they may out-compete native mollusks and grazers for resources such as food. The decrease in the availability of resources is a likely explanation for the decline in species diversity in the presence of NZMS, the negative correlation between the NZMS population and that of mayflies, caddisflies, stoneflies, and chironomids, and the listing of five species of mollusks as endangered species. New Zealand mudsnails may also alter nutrient (carbon and nitrogen) cycling, interrupting energy flow and potentially threatening many other members of their ecosystems.

Commensal/Parasitic Species:

• parasitic flatworms in the genus Microphallus

Predation on New Zealand mudsnails in North America is unknown. They are known to survive passage through the digestive tracts of some birds and fish, including mountain whitefish and rainbow trout.

However, in their native range, the snails are consumed by several species of fish and waterfowl and are infected by as many as 14 parasitic trematodes of the genus Microphallus. Levri and Lively (1996) observed the foraging behaviors of grey ducks (Anas superciliosa), mallard ducks (Anas platyrhynchos), black swans (Cygnus atratus), Canada geese (Branta canadensis), and scaups (Aythya novaeseelandiae), and they reported that grey ducks and mallard ducks are the most likely predators of NZMS.

New Zealand mudsnails that experience predation may have spines on their shells for defense against predators and may forage less frequently in the presence of predators, especially during the morning when waterfowl predators are most active.

Known Predators:

• grey ducks (Anas superciliosa)
• mallard ducks (Anas platyrhynchos)
• black swans (Cygnus atratus)
• Canada geese (Branta canadensis)
• New Zealand scaup, aka black teal (Aythya novaeseelandiae)

Potamopyrgus antipodarum (Potamopyrgus antipodarum (N=Deleatidium lilli)) is prey of:
Salmo trutta
Paranephrops zealandicus
Anguilla dieffenbachii
Gobiomorphus breviceps
Galaxias

Based on studies in:
New Zealand: Otago, Blackrock, Lee catchment (River)
New Zealand: Otago, Dempster's Stream, Taieri River, 3 O'Clock catchment (River)
New Zealand: Otago, Little Kye, Kye Burn catchment (River)
New Zealand: Otago, North Col, Silver catchment (River)
New Zealand: Otago, Sutton Stream, Taieri River, Sutton catchment (River)
New Zealand: Otago, Venlaw, Mimihau catchment (River)
New Zealand: Otago, Stony, Sutton catchment (River)

This list may not be complete but is based on published studies.

Potamopyrgus antipodarum (Potamopyrgus antipodarum (N=Deleatidium lilli)) preys on:
detritus
macrophytes
Achnanthes lanceolata
Cocconeis
Cymbella aspera
Eunotia
Fragilaria vaucheriae
Gomphonema
Stephanodiscus
Aulacoseira
Meridion circulare
Navicula rhynchocephala
Pinnularia
Synedra ulna
Achnanthes linearis
Cyclotella
Cymbella minuta
Epithemia sorex
Gomphonema cf. olivaceum
Gomphonema truncatum
Gomphonema parvulum
Navicula avenacea
Nitzschia
Rhoicosphenia curvata
Surirella tenera
Tabellaria flocculosa
Cyanobacteria
Diatoma heimale
Epithemia zebra
Fragilaria
Gomphoneis herculeana
Frustulia rhomboides
Gomphonema constrictum
Gomphonema subclavatum
Achnanthes saxonica
Cymbella kappii
Gomphonema angustatum
Melosira varians
Surirella
Deleatidium
Nesameletus ornatus
Plantae
Audouinella
Rhopalodia novaezealandiae
Synedra rumpens
Ulothrix
Plant material
Cocconeis placentula
Gomphonema intricatum
Navicula rhynocephala
Nitzschia dissipata
Pinnularia mesolepta
Stauroneis
Surirella biserrata
organic detritus
Stigeoclonium
Calothrix
Achnanthes
Diploneis
Navicula cryptocephala
Eukiefferiella
Navicula
Achnanthes minutissima
Aucalosira
Cyclotella stelligera
Cymbella cuspidata
Epithemia turgida
Fragilaria brevistriata
Gomphonema berggreni
Navicula hungarica
Pinnularia viridis
Nitzschia linearis
green algae

Based on studies in:
New Zealand: Otago, Blackrock, Lee catchment (River)
New Zealand: Otago, Broad, Lee catchment (River)
New Zealand: Otago, Dempster's Stream, Taieri River, 3 O'Clock catchment (River)
New Zealand: Otago, Healy Stream, Taieri River, Kye Burn catchment (River)
New Zealand: Otago, Little Kye, Kye Burn catchment (River)
New Zealand: Otago, Narrowdale catchment (River)
New Zealand: Otago, Stony, Sutton catchment (River)
New Zealand: Otago, Sutton Stream, Taieri River, Sutton catchment (River)
New Zealand: Otago, North Col, Silver catchment (River)
New Zealand: Otago, Venlaw, Mimihau catchment (River)

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: Now present in the Great Lakes and Madison and Missouri rivers (Howells 1999). Since spread to nearly a dozen sites in Lake Ontario (Zaranko et al., 1997). Also Idaho/Wyoming/Montana border area. It has recently been discovered in Pennsylvania at Presque Isle, Erie Co. (Evans and Ray, 2008). Lysne and Pierce (2009) found it rare in Crystal Creek-Spring Creek, Blaine Co., Idaho. Lysne and Clark (2009) found it in the Bruneau River (survey area from Snake River confluence upstream to Hot Creek- 41 km) in Idaho.

10,000 to >1,000,000 individuals

Perception in New Zealand mudsnails is mainly via chemical cues. In their native range, the chemical odor of predatory fish causes the snails to hide under rocks in an attempt to evade predation. They are also able to sense light.

Perception Channels: visual ; chemical

New Zealand mudsnails are ovoviviparous, meaning that the development of embryos in their eggs actually occurs within the female. After completing development, the eggs hatch within the female, and the female then gives birth to the young snails. New Zealand mudsnails have been observed to grow 0.1 mm/day at 21ºC under laboratory conditions, with growth rates depending on the size of the individual. Females reach maturity at 3 to 6 months of age.

Under laboratory conditions, marked individuals were observed to survive over one year. The lifespan of New Zealand mudsnails in natural conditions is unknown.

Range lifespan
Status: captivity: 1 (high) years.

New Zealand mudsnails are dioecious. Populations in New Zealand consist of sexual males and both sexual and asexual females, whereas introduced populations are comprised entirely of asexual females.

In their native range, individuals that reproduce sexually are promiscuous. During copulation, the male is found on top of the shell of a female, and the apertures of the two snails are in contact. Females can either maintain their position and proceed with mating or move in a manner that displaces the males. The duration of copulation is typically between 20 minutes and 1.5 hours. Males do not discriminate between sexual females and asexual or parasitically-castrated females, although their genes will not be passed to the offspring of the latter two types of females.

Populations found in the United States consist of triploid females that reproduce asexually by way of parthenogenesis. This type of asexual reproduction is also observed in their native range and leads to populations of genetically identical females or clones in both their native and introduced habitats.

Mating System: polygynandrous (promiscuous)

In New Zealand, reproduction typically occurs every three months. In the western United Staes, reproduction occurs throughout the year, with seasonal peaks during the months of March and October. Females reach sexual maturity at a shell length of 3 mm and produce approximately 230 young per year. Larger females produce more offspring than smaller females, and asexual females produce double the number of female offspring produced by sexual females. This species is ovoviviparous, carrying as many as 10 to 120 eggs at a time for development and giving birth to live snails. Developing embryos are sometimes present within the reproductive system of asexual females at the time of birth.

Breeding interval: In New Zealand, every 3 months.

Breeding season: Year-round

Range number of offspring: 10 to 120.

Average number of offspring: 21.6.

Range age at sexual or reproductive maturity (female): 3 to 6 months.

Key Reproductive Features: seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); parthenogenic ; sexual ; asexual ; fertilization (Internal ); ovoviviparous

This author found no published information on parental investment by New Zealand mudsnails.

Although females retain their eggs until they hatch, it's not known whether the embryos are nourished in anyway other than via the yolk created when each egg is produced.

Parental Investment: female parental care ; pre-fertilization (Provisioning); pre-hatching/birth (Protecting: Female)

High reproductive capacity in that it is ovoviviparous or populations may be entirely parthenogenic. Only females noted in Lake Ontario (Zaranko et al., 1997). Annual life cycle and reaches sexual maturity at 3.5 mm and can produce an average of 230 juveniles per year.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 21 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 21
Specimens with Barcodes: 25
Species With Barcodes: 1

New Zealand mudsnails are not a protected species in their native range. Outside the native range, actions are being taken against the species to limit its spread as a pest.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Reasons: A widespread species that originally occurred in New Zealand and has since been introduced into Europe and North America and is spreading.

Global Short Term Trend: Increase of 10 to >25%

Degree of Threat: D : Unthreatened throughout its range, communities may be threatened in minor portions of the range or degree of variation falls within natural variation

There are no direct, adverse effects of New Zealand mudsnails on humans, but control of the species is difficult and may be expensive in regions where it is not native.

Because New Zealand mudsnails thrive in disturbed and degraded waters, this species can be used as an indicator of ecosystem status.