Invasion History

First Non-native North American Tidal Record: 1959
First Non-native West Coast Tidal Record: 1959
First Non-native East/Gulf Coast Tidal Record: 1960

General Invasion History:

Faxonius virilis, the Virile Crayfish, was described from Lake Superior and is native to the Great Lakes, southern Arctic Ocean, and northern Mississippi drainages from northern Arkansas, Mississippi, and Tennessee to Alberta and southeastern Quebec, with populations extending west in the Mississippi drainage to Montana and Colorado (Hobbs and Jass 1988). However, part of this range is probably occupied by cryptic species (Filipova et al. 2010). Crocker (1979) considered its range through most of New England as being largely native, but Hobbs (1989) and Taylor et al. (1996) consider it at least partly introduced in this region. At least one cryptic species, F. quinebaugensis, of the F. virilis species complex, is native to south-central New England (Filipova et al. 2010). Faxonius virilis is probably introduced in the Hudson River valley (Smith 1979; Mills et al. 1997). This crayfish was listed as being introduced in seven states (with eight more questionable) (Hobbs 1989), and in 16 states by Taylor et al. (1996). Among states with definite introductions are California, Arizona, Pennsylvania, New Jersey, Maryland, Virginia, West Virginia, and the District of Columbia (Hobbs 1989; Taylor et al. 1996). More recently, it has been collected in the upper Piedmont areas of North Carolina (Cooper et al. 1998), Washington State (Larson et al. 2010) and New Brunswick, Canada (McAlpine et al. 2007). Faxonius virilis has also been introduced into Mexico and unsuccessfully into France (in 1897) and Sweden (in 1960) (Hobbs et al. 1989; Lowery and Holdich 1989). In 2004, it was discovered in ponds leading to the Lee River, North London, England (Ahern et al. 2008) and the Netherlands (Filipova et al. 2004) and is established and spreading in both countries.

North American Invasion History:

Invasion History on the West Coast:

In 1941, Faxonius virilis was collected in Chico, Butte County, California where it had escaped from ponds where it was being kept as laboratory specimens, and by 1959, was found in the Sacramento-San Joaquin Delta, where it is established (Cohen and Carlton 1995). In 2008, this crayfish was found in two lakes in the Puget Sound watershed, Washington, where it may have been introduced for control of vegetation in golf course ponds (Larson and Olden 2008; Larson et al. 2010). It has also been found in five lakes in the upper Columbia River basin (2006-2009, Larson et al. 2010), but has not been found in West coast estuaries outside of the San Francisco estuary.

Invasion History on the East Coast:

Faxonius virilis has been introduced to Atlantic Coast basins from the Black River (St. Johns drainage) New Brunswick, Canada (McAlpine et al. 2007), to the upper Piedmont region of North Carolina (Cooper et al. 1998), but its occurrence in estuarine habitats is poorly documented. Early records in Atlantic drainages include those from 1935 (Worcester County, Massachusetts, Narragansett Bay drainage; Smith 1997), 1956 (Bristol County Massachusetts. Narragansett Bay drainage; USNM 310425, US National Museum of Natural History 2011), 1957 (New York State, upper Hudson drainage; Crocker 1957, cited by Smith 1979), and 1957 (Patapsco River, Maryland; Meredith and Schwartz 1960; Schwartz et al. 1963, United States National Museum of Natural History collections 2007). In the Hudson River drainage, F. virilis was collected in several tributaries near the head of tide (Smith 1979), but we have no specific records from tidal waters. Faxonius virilis has been collected in several tidal or near-tidal tributaries of the upper Chesapeake Bay including Curtis Creek (Meredith and Schwartz 1960; Schwartz et al. 1963; USNM 203786 United States National Museum of Natural History collections 2007), the Gunpowder River (Killian et al. 2010), the Bush River (Killian et al. 2010), and the upper tidal Patuxent River (Killian et al. 2010). It has been reported from the District of Columbia (Hobbs 1989), but Maryland records from recent surveys in the Potomac are all from the Piedmont region (Killian et al. 2010). In the Delaware River, it was collected in 2007 near the suburbs of Philadelphia, within 5 km of the tidal portion of the river (Lieb et al. 2011). Likely sources of these many introductions include the sale of crayfish for bait, biology classes and aquarium pets (Smith 1997; Kilian et al. 2010).

Invasion History Elsewhere in the World:

Faxonius  virilis has been successfully introduced into Mexico, but early introductions in France (1897) and Sweden (1960) failed (Hobbs et al. 1989; Lowery and Holdich 1989). In 2004, it was discovered in ponds leading to the Lee River, North London, England (Ahern et al. 2008) and the Netherlands (Filipova et al. 2010) and is established and spreading in both countries. Genetic testing found that the established European populations came from a clade whose North American distribution is unknown (Filipova et al. 2010).


The Virile Crayfish (Faxonius virilis) has a smooth ovoid carapace with a rostrum which is longer than it is wide, lined with small tubercles or spines, and without a dorsal keel. There are no spines in the hepatic (cheek) region. There is a prominent spine on the postorbital ridge and another cervical spine where the head (cephalon) joins the thorax. The antennal scale terminates in a small spine. The claw (chela) is smooth and robust, and about equal to the carapace length in males, ~73% in females. There is a long plumose seta at the base of the fixed finger of the claw. In males, the first pleopods end in two curved terminal elements. In Form I (reproductive) males, the outer branch of the first pleopods are sclerotized (hardened) and the 3rd segments (ischia) of the 3rd pair of walking legs bears copulatory hooks. In the female, the annulus ventralis (seminal receptacle) is a rhombus-like structure, 1.5 X as wide as long, with a deep depression in the center, located between the 4th and 5th walking legs. The carapace is mostly chestnut brown, but darker brown or black on rostral margins. The dorsal surface of the cheliped (claw-leg) is blue-gray to emerald green, often mottled with splotches of black and blue, and with cream to yellow spines and tubercles (Hobbs and Jass 1988; Jezerinac et al. 1995).

Faxonius virilis is part of a species complex, which includes several newly recognized species (F. deanae-New Mexico, F. nais- Oklahoma, F. quinebaugensis- central Massachusetts) and several undescribed species (Filipova et al. 2010).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Malacostraca
Subclass:   Eumalacostraca
Superorder:   Eucarida
Order:   Decapoda
Suborder:   Pleocyemata
Infraorder:   Stenopodidea
Superfamily:   Astacoidea
Family:   Cambaridae
Genus:   Faxonius
Species:   virilis


Cambarus debilis (Bundy, 1876)
Cambarus rusticus (Bundy, 1883)
Cambarus virilis (Hagen, 1870)
Cambarus wisconsinesis (Bundy, 1876)
Faxonius virilis (Penn, 1943)

Potentially Misidentified Species

Faxonius limosus
Spinycheek Crayfish- Native to NE US, introduced to Europe

Faxonius quinebaugensis
Quinebaug Crayfish- Native to central Massachusetts, Connecticut

Faxonius rusticus
Rusty Crayfish- Native to south-central US, introduced to many US rivers, including the nontidal Hudson, Delaware, Susquehanna, and Potomac watersheds.



Ecology Virile Crayfish (Faxonius virilis inhabit streams, ponds and lakes in a variety of habitats, including rocky, muddy, and vegetated areas. Burrowing has been observed in parts of its range, but in Wisconsin, they made only shallow excavations (Hobbs and Jass 1989). The extent to which this crayfish inhabits tidal fresh or brackish estuaries is unclear, though it does tolerate brackish water up to at least 14 PSU (Kendall and Schwartz 1964).


aquatic plants, worms, snails, bivalves, carrion


fishes, turtles, snakes, birds, raccoons, otters


Other crayfish species

Trophic Status:




General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatSwampNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatRockyNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Life History

Life History- Freshwater crayfish of the family Cambaridae, mate by internal fertilization, with the male inserting pleopods into the females seminal (annulus ventralis) which is between the 4th and 5th walking legs. The female curls her abdomen far forward, to create a chamber in which the eggs are driven by the pleopods. The mass of eggs becomes attached under the tail. Larval development takes place inside the egg and the young hatch as miniature adults (Barnes 1983).

Male cambarid crayfish show sharp morphological changes with season. At the start of the breeding season, they molt into a sexually competent stage (Form I), marked by lengthening and stiffening of the modified 1st pleopods, with more pronounced ischial spines (in the basal segments of the 3rd walking leg, and enlarged chelipeds). After breeding, the crayfish molts back into Form II, with the 1st pleopods less differentiated and soft, the ischial spines are reduced, and the chelipeds are less robust (Hobbs 1991).

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Based on geographical range (Hobbs and Jass 1988)
Maximum Temperature (ºC)39Survival values are from a Critical Thermal Maximum experiment (slow, steady temperature increase), of animals acclimated at 25 C (Claussen 1980).
Minimum Salinity (‰)0This is a freshwater animal.
Maximum Salinity (‰)14Note that the mortality was high in fresh water controls, and intermediate salinities between 14 and 30 were not used (Kendall and Schwartz 1964).
Minimum Dissolved Oxygen (mg/l)2Field- In the Patapsco River, O. virilis tolerated D.O. levels of 2 ppm (Schwartz et al. 1963) but this species is less tolerant of low O2 than other species (e.g. O. immunis, Bovbjerg 1970).
Minimum Reproductive Temperature10Field- Schwartz et al. 1963
Maximum Length (mm)60Hobbs and Jass 1988; Mitchell and Smock 1991
Broad Temperature RangeNoneCold temperate
Broad Salinity RangeNoneNontidal Limnetic-Mesohaline

General Impacts

Economic Impacts-

In North America, crayfish of the genus Faxonius have, at present, only minor economic importance. They are harvested for biological supply houses to be sold for research and teaching purposes. Only a small quantity is sold for human consumption, mainly in the state of Wisconsin (Momot 1989). However, they are widely sold and used as bait (Hobbs and Jass 1988; Kilian et al. 2010).

Ecological Impacts-

Competition- The spread of Faxonius virilis in the Chesapeake Bay watershed was accompanied by the displacement of F. limosus (Spinycheek Crayfish or Coastal Plains River Crayfish) and Cambarus bartonii (Appalachian Brook Crayfish) in the Patapsco and other rivers (Schwartz et al. 1963). Its displacement of these species is believed to be due to wider environmental tolerances, larger size, and more aggressive behavior (Bovberg 1970; Odell and Grimm 1966; Schwartz et al. 1963). Faxonius limosus is now probably imperiled in Maryland (Norden 1995 personal communication), and has been suggested as a Federal endangered species, largely because of its displacement by F,. virilis and F rusticus (Rusty Crayfish) in much of its range (Jezerinac et al. 1995; Kilian et al. 2010). In the upper Sacramento River watershed, the introduced crayfish F. virilis and Pacifastacus leniusculus (Signal Crayfish) were believed to be competing with the endangered native P. fortis (Shasta Crayfish) (Cohen and Carlton 1995). In England and the Netherlands, where it has been recently introduced, it is displacing the previously introduced O. limosus (Holdich et al. 2009).

Regional Impacts

M130Chesapeake BayEcological ImpactCompetition
The spread of Faxonius virilis was accompanied by the displacement of Faxonius limosus (Spinycheek Crayfish or Coastal Plains River Crayfish) and Cambarus bartonii (Appalachian Brook Crayfish) in the Patapsco and other rivers (Schwartz et al. 1963; Kilian et al. 2010). Its displacement of these species is believed to be due to wider environmental tolerances, larger size, and more agressive behavior (Bovbjerg 1970; Odell and Grimm 1966; Schwartz et al. 1963). Faxonius limosus is now probably imperiled in Maryland (Norden 1995 personal communication), and has been suggested as a federal endangered species, largely because of its displacement by F. virilis and F. rusticus (Rusty Crayfish) in much of its range (Jezerinac et al. 1995; Kilian et al. 2010).
P090San Francisco BayEcological ImpactCompetition
In the upper Sacramento River watershed, the introduced crayfish O. virilis and Pacifastacus leniusculus (Signal Crayfish) were believed to be competing with the endangered native P. fortis (Shasta Crayfish) (Cohen and Carlton 1995).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
M130 Chesapeake Bay 1960 Def Estab
P090 San Francisco Bay 1959 Def Estab
NA-S3 None 0 Native Estab
GL-III Lake Ontario 0 Native Estab
GL-II Lake Erie 0 Native Estab
GL-I Lakes Huron, Superior and Michigan 0 Native Estab
LWINNI Lake Winnipeg 0 Native Estab
LNIPIGON Lake Nipigon 0 Native Estab
LWINNIPOG Lake Winnipogosis 0 Native Estab
LMANIT Lake Manitoba 0 Native Estab
L011 _CDA_L011 (Baptism-Brule) 0 Native Estab
L084 _CDA_L084 (Lake St. Clair) 0 Native Estab
L082 _CDA_L082 (Lake St. Clair) 0 Native Estab
GL-II Lake Erie 0 Native Estab
L066 _CDA_L066 (Thunder Bay) 0 Native Estab
L062 _CDA_L062 (Carp-Pine) 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Ahern, Daniel; England, Judy; Ellis, Adam (2008) The virile crayfish, Orconectes virilis (Hagen, 1870) (Crustacea: Decapoda: Cambaridae), identified in the UK, Aquatic Invasions 3(1): 102-104

Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

Bovbjerg, Richard V. (1970) Ecological isolation and competitive exclusion in two crayfish (Orconectes virilis and Orconectes immunis), Ecology 51: 225-236

Claussen, Dennis L. (1980) Thermal acclimation in the crayfish, Orconectes rusticus and O. virilis, Comparative Biochemistry and Physiology <missing volume>: 377-384

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Cooper, John E.; Braswell, Alvin L; McGrath, Christopher (1998) Noteworthy distribution records for crayfishes (Decapoda: Cambaridae) in North Carolina, Journal of the Elisha Mitchell Scientific Society 114(1): 1-10

Crocker, Denton W. (1979) The crayfishes of New England, Proceedings of the Biological Society of Washington 92(2): 225-252

Faxon, Walter (1884) Descriptions of a new species of Cambarus, to which is added a synonymical list of the known species of Cambarus and Astacus., Proceedings of the American Academy of Arts and Sciences 20: 107-158

Faxon, Walter (1885) Revision of the Astacidae, Memoirs of the Museum of Comparative Zoology, Harvard University 10(4): 1-186

Filipova, Lenka; Holdich, David M.; Lesobre, Jerome; Grandjean, Frederic; Petrusek, Adam (2010) Cryptic diversity within the invasive virile crayfish Orconectes virilis (Hagen, 1870) species complex: new lineages recorded in both native and introduced ranges, Biological Invasions 12: 983-989

Hobbs III, H. H.; Jass, Joan P.; Huner, Jay V. (1989) A review of global crayfish introductions with particular emphasis on two North American species (Decapoda, Cambaridae)., Crustaceana 56(3): 299-316

Hobbs, H. H. III (1991) Ecology and Classifiaction of North American Freshwater Invertebrates, Academic Press, San Diego. Pp. 823-858

Hobbs, Horton H. (1989) An illustrated checklist of the crayfishes of American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae), Smithsonian Contributions to Zoology <missing volume>(480): 1-92

Hobbs, Horton H.; Jass, Joan P. (1988) <missing title>, Milwaukee Public Museum, Milwaukee, WI. Pp. <missing location>

Holdich, D. M.; Reynolds, J. D.; Souty-Grosset, C.; Sibley, P. J. (2009) A review of the ever increasing threat to European crayfish from non-indigenous crayfish species, Knowledge and Management of Aquatic Ecosystems 11: 394-395

Jezerinac, Raymond F.; Stocker, G. Whitney; Tarter, Donald C. (1995) The crayfishes (Decapoda: Cambaridae) of West Virginia, Bulletin of the Ohio Biological Survey 10(1): 1-193

Kendall, Arthur; Schwartz, Frank J. (1964) Salinity tolerance of two Maryland crayfishes, Ohio Journal of Science 64(6): 403-409

Kilian, Jay V. and 6 authors (2010) The status and distribution of Maryland crayfishes, Southeastern Naturalist 9(Special Issue 3): 11-32

Larson, Eric R.; Busack, Craig A.; Anderson, Jon D.; Olden, Julian D. (2010) Widespread distribution of the non-native northern crayfish (Orconectes virilis) in the Columbia rRver basin, Northwest Science 84(1): 108-111

Larson, Eric R.; Olden, Julian D. (2008) Do schools and golf courses represent emerging pathways for crayfish invasions?, Aquatic Invasions 3(4): 465-468

Lieb, David A. and 5 authors (2011) Conservation and management of crayfishes: lessons from Pennsylvania, Fisheries 36(10): 489-507

Lieb, David A.; Bouchard, Raymond W.; Carline, Robert F. (2011) Crayfish fauna of southeastern Pennsylvania: distributions, ecology, and changes over the last century, Journal of Crustacean Biology 31(1): 166-178

Lodge, David M. and 17 authors (2012) Global introductions of crayfishes: evaluating the impact of species invasions on ecosystem services, Annual Review of Ecology and Systematics 43: 449-472

Love, Joy; Savino, Jacqueline F. (1993) Crayfish (Orconectes virilis) predation on zebra mussels (Dreissena polymorpha), Journal of Freshwater Ecology 8(3): 253-259

Lowery, R. S.; Holdich, D. M. (1989) Pacifiastacus lenisculus in North America, with details of the distribution of introduced and native crayfish species in Europe., In: Holdich, D. M., and Lowery, R. S.(Eds.) Freshwater Crayfish: Biology, Management, and Exploitation.. , London. Pp. 283-308

Lucena, Rudá Amorim; Christoffersen, Martin Lindsey (2018) Anoplodactylus (Pycnogonida: Phoxichilidiidae) from Brazil, ew records and two new species, Turkish Journal of Zoology 42: 372-388

McAlpine, Donald J.; McAlpine, Amber H. E.; Madden, Alan (2006) Occurrence of the potentially invasive crayfish Orconectes virilis in eastern New Brunswick, Canada., Crustaceana 80: 509-511

Meredith, W.G.; Schwartz, F.J. (1960) Maryland Crayfishes, Maryland Department of Research and Education Series 46: 1-32

Mills, Edward L.; Scheuerell, Mark D.; Carlton, James T.; Strayer, David (1997) Biological invasions in the Hudson River: an inventory and historical analysis., New York State Museum Circular 57: 1-51

Mitchell, Douglas J.; Smock, Leonard A. (1991) Distribution, life history, and production of crayfish in the James River, Virginia, American Midland Naturalist 126: 353-363

Momot, W. T. (1989) Freshwater Crayfish: Biology, Management, and Exploitation, Croome Helme, London. Pp. 262-282

Odell, J. Mark; Grimm, F. Wayne (1966) Orconectes virilis in Maryland, The Journal of the Elisha Mitchell Scientific Society 82(2): 102

Olden, Julian D.; Larson, Eric R.; Mims, Meryl C. (2009) Home-field advantage: native signal crayfish (Pacifastacus leniusculus) out consume newly introduced crayfishes for invasive Chinese mystery snail (Bellamya chinensis), Aquatic Ecology 43: 1073-1084

Riegel, J. A. (1959) The systematics and distribution of crayfishes in California, California Fish and Game 45(1): 29-50

Schwartz, Frank J.; Rubelmann, Robert; Allison, James (1963) Ecological population expansion of the introduced crayfish Orconectes virilis., Ohio Journal of Science 63(3): 266-273

Siewert, Horst F.; Buck, John P. (1991) Effects of low pH on survival of crayfish (Orconectes virilis), Journal of Freshwater Ecology 6(1): 87-91

Smith, Douglas G. (1979) New locality records of crayfishes from the middle Hudson River system, Ohio Journal of Science 79(3): 133-135

Smith, Douglas G. (1991) <missing title>, University of Massachusetts, Boston. Pp. 1-236

Smith, Douglas G. (1997) An annotated checklist of malacostracans (Crustacea) inhabiting southern New England fresh waters, Journal of Freshwater Ecology 12(2): 217-223

Taylor, Christopher A.; Warren, Melvin L.; Fitzpatrick, J. F., Jr., Hobbs, Horton H.., Jezerinac, Raymond F., Pflieger, William L., Robison, Henry W. (1996) Conservation status of crayfishes of the United States and Canada, Fisheries 21(4): 25-37

Turner, Ruth D.; Boss, Kenneth (1962) The genus Lithophaga in the Western Atlanitc, Johnsonia 4(41): 81-116

2002-2021 Invertebrate Zoology Collections Database. <missing description>