Orconectes rusticus - Rusty Crayfish

Information Last Reviewed Spring 2007

The rusty crayfish has been a reported invader since at least the 1930’s. Its further spread is of great concern since the prior areas of invasion have led to severe impacts on native flora and fauna.

Taxonomy

Identification

General Biology

Life Cycle

Habitat Characteristics

Taxonomy

Phylum: Arthropoda

Subphylum: Crustacea

Class: Malacostraca

Order: Decapoda

Family: Cambaridae

Identification

Juvenile Morphology

Eggs hatch into "bulbous-headed, thin-tailed pink juveniles" $image\10.jpg$
After hatching, juveniles undergo multiple molts and gradually begin to look like small adults $image\10.jpg$

$image\orusticus1.jpg$

Adult Orconectes rusticus (Image from: http://www.wildlife.state.nc.us/pg07_WildlifeSpeciesCon/nccrayfishes/o_rusticus/mainphoto.jpg

Adult Morphology

Prominent rusty-colored spot on each side of the carapace (#1 on figure) $image\24.jpg$
Rust-colored band down the center of the back side of the abdomen $image\24.jpg$
Overall tan color, especially on legs $image\24.jpg$
Tips of claws have black bands (#2 on figure) $image\24.jpg$
Oval gap on claws when closed (#3 on figure) $image\24.jpg$

Distinguishing Characteristics

Most easily distinguished from similar species by the rusty spots on each side of its carapace $image\24.jpg$
Sometimes confused with O. luteus (Golden Crayfish) which has a light olive green color as opposed to the tan color of O. rusticus $image\24.jpg$

General Biology

Behavior

Larger and more aggressive than most similar species $image\5.jpg$
Better competitor for food and habitat than similar species $image\5.jpg$
Adult males molt at least twice a year $image\2.jpg$ , $image\10.jpg$
Some population can reach higher densities (up to 13 adults per square yard) than those of similar species $image\10.jpg$

Diet

Juveniles

Omnivorous
Similar diets to adults $image\15.jpg$
Feed on benthic invertebrates more often than adults $image\7.jpg$ , $image\15.jpg$

Adults

Omnivorous
Adult diets include macrophytes (large submersed algae particles), invertebrates, and periphyton (algae and microbes attached to objects submersed in water) $image\14.jpg$
Of the invertebrates, snails are especially targeted as food $image\11.jpg$

Life Cycle

Growth

Juveniles grow faster than juveniles of other similar species $image\10.jpg$
Reach a maximum size of roughly 4 inches from head to tail plus about another 2 inches for the length of their chelae (claws) $image\10.jpg$

Maturity

Reach maturity after about 1 year $image\21.jpg$

Breeding

Breed "explosively" in the spring when water temperatures begin rising $image\2.jpg$
During mating season males have enlarged chelae (claws) much larger than those of females $image\2.jpg$
Males use their enlarged chelae to pin down the female during copulation $image\2.jpg$
During copulation the male deposits sperm into a receptacle on the female where it is stored until she extrudes and broods her eggs $image\2.jpg$
Males often place a mating plug in the female after he has successfully mated with her $image\2.jpg$
Males often fight with other males and often interrupt copulating pairs $image\2.jpg$
Following copulation females isolate themselves and extrude, fertilize, and brood their eggs $image\2.jpg$
Females usually carry eggs and juveniles for 6–8 weeks $image\1.jpg$

Eggs

Females lay up to 200 eggs $image\10.jpg$
Eggs stay attached to the female’s abdomen until they hatch $image\10.jpg$

Juveniles

After hatching, juveniles stay near the female for about two weeks $image\10.jpg$
During these first two weeks, juveniles molt several times and slowly take the shape of a small adult $image\10.jpg$

Habitat Characteristics

Preferred Environment

Prefer cobble habitat, which allows them to hide if necessary $image\8.jpg$ , $image\23.jpg$
Found in both lotic (running water; streams, rivers) and lentic (standing water; lakes) environments $image\23.jpg$
Show a tendency to favor clear water $image\6.jpg$
Usually found at water depths of less than 1 m, although in Lake Michigan they have been collected at a depth of 14.6 m $image\23.jpg$
Adults prefer deeper (>20 cm) pool areas $image\4.jpg$ , $image\17.jpg$
Juveniles normally occupy shallow (<15 cm) areas bordering stream edges $image\4.jpg$

Temperature

Prefer temperatures between 20 °C and 25 °C $image\17.jpg$
In native range, specifically Ohio, they may be seasonally exposed to water temperatures ranging from near 0° C to 39° C $image\17.jpg$
Adults can force juveniles into warmer waters, causing them to often be found in water 1.5° C to 6.8° C warmer than adults $image\17.jpg$
At temperatures >30° C adults have been observed digging burrows in sand and gravel beneath rocks near the shore to escape the heat $image\16.jpg$

Oxygen

Prefer well-oxygenated water $image\6.jpg$

Salinity

Unknown

Water Quality

Human disturbances that change the thermal regime of the water body may allow the rusty crayfish to invade new waters and displace native species $image\17.jpg$

Distribution

Native Range

Western Ohio, Indiana, Kentucky, and possibly parts of Illinois $image\17.jpg$ , $image\23.jpg$
Native to the Ohio River and its tributaries $image\23.jpg$

North American Distribution

Established:

Found in streams, rivers, and lakes in Illinois, Iowa, Maine, Michigan, Minnesota, New Hampshire, New Mexico, North Carolina, Pennsylvania, Tennessee, Vermont, West Virginia, and Wisconsin $image\23.jpg$ , $image\24.jpg$
Populations may be established in Missouri $image\22.jpg$
Great Lakes: Believed to be established in Lake Huron, Lake Ontario, Lake Michigan, Lake Erie, Lake Superior $image\13.jpg$
Found in Ontario, Canada $image\3.jpg$
Range expansion is ongoing in all directions from the current range $image\13.jpg$

Probable Means of Introduction

Escaped or released from anglers using them as bait $image\5.jpg$ , $image\23.jpg$

Impacts

Negative

Reduce abundance of macrophytes (water plants) $image\6.jpg$ , $image\12.jpg$
Reduce abundance of snails $image\12.jpg$
Cause a decline in the number of snail species present $image\12.jpg$
Out-competes native crayfish species in many lakes $image\15.jpg$ , $image\18.jpg$
Shown to cause a decline in the abundance of benthic invertebrates and fish in some lakes $image\15.jpg$ , $image\18.jpg$
Competes with juvenile game fish for benthic invertebrates $image\15.jpg$
Laboratory experiments show that they may cause a decline in fish abundance by feeding on fish eggs $image\6.jpg$ , $image\9.jpg$
Shown to be able to hybridize with native crayfish species $image\19.jpg$

Positive

Increase the amount of live algae $image\12.jpg$
Increase the quantity and quality of periphyton (algal and bacterial covering on rocks) by reducing the number of snails $image\12.jpg$
Shown to help slow the spread of the invasive zebra mussel in some water bodies $image\20.jpg$

Management

Control Measures

Increased human harvesting for food may slow their spread, but it is unlikely that this can significantly reduce their abundance $image\10.jpg$
Protect sport-fish populations in order to increase the level of predation on the crayfish $image\10.jpg$
Increased public awareness by state and federal agencies by distributing brochures and posting signs outlining the harmful effects of using and releasing non-native bait crayfish into new regions

Literature Cited

Berrill, M. 1978. Distribution and ecology of crayfish in the Kawartha Lakes region of southern Ontario. Canadian Journal of Zoology. 56:166-177

Berrill, M. and M. Arsenault. 1984. The breeding behavior of a northern temperate orconectid crayfish, Orconectes rusticus. Animal Behavior. 32:333-339

Berrill, M., L. Hollett, A. Margosian, and J. Hudson. 1985. Variation in tolerance to low environmental pH by the crayfish Orconectes rusticus, O. propinquus, and Cambarus robustus. Canadian Journal of Zoology. 63:2586-2589

Butler, M.J. and R.A. Stein. 1985. An analysis of the mechanisms governing species replacements in crayfish. Oecologia. 66:168-177

Byron, C.J. and K.A. Wilson. 2001. Rusty crayfish (Orconectes rusticus) movement within and between habitats in Trout Lake, Vilas County, Wisconsin. Journal of the North American Benthological Society. 20:606-614

Capelli, G.M. 1982. Displacement of northern Wisconsin crayfish by Orconectes rusticus (Girard). Limnology and Oceanography. 27:741-745

Hanson, J.M., P.A. Chambers, and E.E. Prepas. 1990. Selective foraging by the craysifh Orconectes virilis and its impact on macroinvertebrates. Freshwater Biology 24:69-80

Hill, A.M. and D.M. Lodge. 1994. Diel changes in resource demand: Competition and predation in species replacement among crayfishes. Ecology. 75:2118-2126

Horns, W.H. and J.J. Magnuson. 1981. Crayfish predation on lake trout eggs in Trout Lake, Wisconsin. Rapp. P.-v. Reun. Cons. Int. Explor. Mer. 178:299-303

Lodge, D.M., A.L. Beckel, and J.J. Magnuson. 1985. Lake-bottom tyrant. Natural History. 94:32-37

Lodge, D.M. and Lorman, J.G. 1987. Reductions in submersed macrophyte biomass and species richness by the crayfish Orconectes rusticus. Canadian Journal of Fisheries and Aquatic Sciences. 44:591-597

Lodge, D.M., M.W. Kershner, J.E. Aloi, and A.P. Covich. 1994. Effects of an omnivorous crayfish (Orconectes rusticus) on a freshwater littoral food web. Ecology. 75:1265-1281

Lodge, D.M., C.A. Taylor, D.M. Holdich, J. Skurdal. 2000. Nonindigenous crayfishes threaten North American freshwater biodiversity: Lessons from Europe. Fisheries. 25:7-20

Lorman, J.G. 1980. Ecology of the crayfish Orconectes rusticus in northern Wisconsin. PhD Dissertation, University of Wisconsin, Madison, Wisconsin

Momot, W.T. 1992. Further range extensions of the crayfish Orconectes rusticus in the Lake Superior Basin of Northwestern Ontario. The Canadian Field-Naturalist. 106:397-399

Mundahl, N.D. 1989. Seasonal and diel changes in thermal tolerance of the crayfish Orconectes rusticus, with evidence for behavioral thermoregulation. Journal of the North American Benthological Society. 8:173-179

Mundahl, N.D. and M.J. Benton. 1990. Aspects of the thermal ecology of the rusty crayfish Orconectes rusticus (Girard). Oecologia. 82:210-216

Olsen, T.M., D.M. Lodge, G.M. Capelli, and R.J. Houlihan. 1991. Mechanisms of impact of an introduced crayfish (Orconectes rusticus) on littoral congeners, snails, and macrophytes. Canadian Journal of Fisheries and Aquatic Sciences. 48:1853-1861

Pennak, R.W. 1989. Fresh-water invertebrates of the United States. Protozoa to Mollusca, 3rd ed. John Wiley and Sons, Inc. New York. 628p

Perry, W.L., D.M. Lodge, and G.A. Lamberti. 2000. Crayfish (Orconectes rusticus) impacts on Zebra Mussel (Dreissena polymorpha) recruitment, other macroinvertebrates and algal biomass in a lake-outlet stream. American Midland Naturalist. 144:308-316

Perry, W.L., J.L. Feder, and D.M. Lodge. 2001. Implications of hybridization between introduced and resident Orconectes crayfishes. Conservation Biology. 15:1656-1666

Pfleiger, W.L. 1996. The Crayfishes of Missouri. Missouri Department of Conservation. Jefferson City, Missouri. 152p

Taylor, C.A. and M. Redmer. 1996. Dispersal of the crayfish Orconectes rusticus in Illinois, with notes on species displacement and habitat preference. Journal of Crustacean Biology. 16:547-551

Wetzel, J.E., W.J. Poly, and J.W. Fetzner Jr. 2004. Morphological and genetic comparisons of golden crayfish, Orconectes luteus, and rusty crayfish, O. rusticus, with range corrections in Iowa and Minnesota. Journal of Crustacean Biology. 24:603-617

Additional Literature:

Bills, T.D. and L.L. Marking. 1988. Control of nuisance populations of crayfish with traps and toxicants. The Progressive Fish-Culturist. 50:103-106

Bouchard, R.W. and H.W. Robinson. 1980. An inventory of the decapod crustaceans (crayfishes and shrimps) of Arkansas with a discussion of their habitats. Arkansas Academy of Science Proceedings 34:22-30

Capelli, G.M. and J.J. Magnuson. 1983. Morphoedaphic and biogeographic analyses of crayfish distribution in Northern Wisconsin. Journal of Crustacean Biology. 3:548-564

Capelli, G.M. and B.L. Munjal. 1982. Aggressive interactions and resource competition in relation to species displacement among crayfish of the genus Orconectes. Journal of Crustacean Biology 2:486-492

DiDonato, G.T. and D.M. Lodge. 1993. Species replacements among Orconectes crayfishes in Wisconsin lakes: The role of predation by fish. Canadian Journal of Fisheries and Aquatic Sciences 50:1484-1488

Garvey, J.E., R.A. Stein, and H.M. Thomas. 1994. Assessing how fish predation and interspecific prey competition influence a crayfish assemblage. Journal of Ecology 75:532-547

Helgen, J.C. 1990. The distribution of crayfish in Minnesota. Section of Fisheries Investigational Report Number 405. Minnesota Department of Natural Resources. 106 pp

Hill, A.M. and D.M. Lodge. 1999. Replacement of resident crayfishes by an exotic crayfish: The roles of competition and predation. Ecological Applications 9:678-690

Hill, A.M., D.M. Sinars, and D.M. Lodge. 1993. Invasion of an occupied niche by the crayfish Orconectes rusticus: Potential importance of growth and mortality. Oecologia 94:303-306

Hobbs, H.H. and J.P. Jass. 1988. The crayfishes and shrimp of Wisconsin. Milwaukee Public Museum, Milwaukee, WI. 177 pp

Lodge, D.M., T.K. Kratz, and G.M. Capelli. 1986. Long-term dynamics of three crayfish species in Trout Lake, Wisconsin. Canadian Journal of Fisheries and Aquatic Sciences 43:993-998

Luttenton, M.R., M.J. Horgan, and D.M. Lodge. 1998. Effects of three Orconectes crayfishes on epilithic microalgae: a laboratory experiment. Crustaceana 71:845-855

Jones, P.D. and W.T. Momot. 1983. The bioenergetics of crayfish in two pothole lakes. Freshwater Crayfish 5:193-209

Seiler, S.M. and A.M. Turner. 2004. Growth and population size of crayfish in headwater streams: Individual- and higher-level consequences of acidification. Freshwater Biology 49:870-881

Stein. R.A. 1977. Selective predation, optimal foraging and the predator-prey interaction between fish and crayfish. Journal of Ecology. 58:1237-1253

Taylor, C.A. 2000. Systematic studies of the Orconectes juvenilis comples (Decapoda: Cambaridae), with descriptions of two new species. Journal of Crustacean Biology 16: 547-551

Web Sites

http://www.issg.org/database/species/ecology.asp?si=217&fr=1&sts=

http://www.great-lakes.net/envt/flora-fauna/invasive/rusty.html

http://www.seagrant.umn.edu/exotics/rusty.html