Animal Diversity Web

Ge­o­graphic Range

The rusty cray­fish is an in­vader species in north­ern lakes and streams of the Great Lakes re­gion. Na­tive to the Ohio River Basin and Ohio, Ken­tucky, Ten­nessee, In­di­ana, and Illi­nois, they have ex­panded their range to Michi­gan, Min­nesota, Wis­con­sin, Mis­souri, Iowa, Penn­syl­va­nia, New York, New Jer­sey, New Eng­land (ex­cept Rhode Is­land), and parts of On­tario, Canada. (Gun­der­son, 1995)

• Biogeographic Regions
• nearctic
  • introduced
  • native

Habi­tat

This cray­fish in­hab­its per­ma­nent streams, lakes and ponds that have rocky sub­strate and logs or de­bris as cover. They will in­habit pools of still water or fast-flow­ing streams. (Cran­dall and Fet­zner, 2003; Gun­der­son, 1995)

• Habitat Regions
• freshwater

Phys­i­cal De­scrip­tion

Rusty cray­fish have ro­bust claws un­like other mem­bers of the genus Or­conectes. They are dark red­dish, brown and have dark, rusty spots on each side of the cara­pace at the base of the cephalotho­rax. (Gun­der­son, 1995)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Range length

  10.2 (high) cm

  4.02 (high) in

De­vel­op­ment

De­pend­ing on the water tem­per­a­ture, rusty cray­fish eggs hatch in 3 to 6 weeks. Young cray­fish will un­dergo 3 to 4 molts while at­tached to the mother's swim­merets and re­main with the mother for sev­eral weeks. Once the young have left, they un­dergo 8 to 10 molts be­fore be­com­ing ma­ture. Ma­tu­rity usu­ally oc­curs the fol­low­ing year. Ma­tu­rity is con­sid­ered to be at a length of 4.4 cm. After ma­ture, adult males will molt twice an­nu­ally, and adult fe­males will molt once an­nu­ally. (Gun­der­son, 1995)

Re­pro­duc­tion

Rusty cray­fish mate in late sum­mer, early fall or early spring. Males trans­fer sperm to the fe­males, but ex­ter­nal fer­til­iza­tion does not occur until the water tem­per­a­ture in­creases. The ex­pelled eggs are fer­til­ized by the sperm and are at­tached to the swim­merets un­der­neath the cray­fish's ab­domen with white patches. These white patches are called glair, and and the eggs ad­here to this mu­cus-like sub­stance. From 80 to 575 eggs are laid. (Gun­der­son, 1995)

• Key Reproductive Features
• fertilization
  • external
• delayed fertilization

Lifes­pan/Longevity

The rusty cray­fish typ­i­cally lives to be 3 to 4 years old. (Gun­der­son, 1995)

Be­hav­ior

The rusty cray­fish does not ex­ca­vate deep bur­rows. They may dig shal­low pock­ets under rocks or de­bris. The rusty cray­fish are ag­gres­sive and will force na­tive cray­fish from day­time hid­ing areas. When threat­ened, they as­sume a "claws-up" pos­ture to pre­vent fish pre­da­tion.

In ad­di­tion, their ag­gres­sion oc­curs with dis­crete pos­tures that lead to fight­ing. When one rusty cray­fish comes in con­tact with an­other, the meral spread is the first threat dis­play pos­ture to occur. Next, wrestling oc­curs, but claw use is re­strained as the rusty cray­fish par­take in this phase of an ag­gres­sive en­counter over a pe­riod of time. Fi­nally, un­re­strained use of the claws oc­curs dur­ing a brief pe­riod of time. (Gun­der­son, 1995; Huber, 1999)

• Key Behaviors
• motile
• territorial
• dominance hierarchies

Com­mu­ni­ca­tion and Per­cep­tion

Dur­ing en­coun­ters, rusty cray­fish re­spond to each other de­pend­ing on the pres­ence of urine. The stronger the odor, which serves as a chem­i­cal cue, the shorter in du­ra­tion and the lesser the ag­gres­sion dur­ing a first ag­o­nis­tic in­ter­ac­tion. In ad­di­tion, urine serves as a recog­ni­tion cue in that a rusty cray­fish that won a first fight over an op­po­nent will rec­og­nize that op­po­nent and dis­play dom­i­nance dur­ing a sec­ond ag­gres­sive en­counter, but the sec­ond en­counter will be shorter in du­ra­tion. (Zu­landt-Schnei­der, et al., 2001)

• Communication Channels
• chemical

Food Habits

The rusty cray­fish is a vo­ra­cious feeder be­cause of its high meta­bolic rate. Ju­ve­nilles feed on ben­thic in­ver­te­brates and fish eggs.

Foods eaten in­clude: aquatic plants, snails, clams, leeches, aquatic in­sects, other aquatic crus­taceans and fish eggs. (Gun­der­son, 1995)

Pre­da­tion

Rusty cray­fish will used their hooked claws in a de­fen­sive pos­ture to pro­tect them­selves from fish preda­tors. (Gun­der­son, 1995)

• Known Predators

  • fish

Ecosys­tem Roles

Be­cause of its ag­gres­sive na­ture, the rusty cray­fish is re­plac­ing na­tive Great Lakes cray­fish such as Or­conectes propin­quus. Many or­gan­isms live on the ex­oskele­ton and other or­gan­isms are in­ter­nally par­a­sitic in cray­fish. (Crocker and Barr, 1968; Gun­der­son, 1995)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Among agen­cies con­cerned about ecosys­tem man­age­ment in the Great Lakes re­gion, there is a de­bate about using rusty cray­fish to con­trol Eurasian wa­ter­mil­foil, an in­va­sive aquatic plant. (Gun­der­son, 1995)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

These cray­fish have dis­placed na­tive species. They may af­fect the fish­eries in­dus­try since they feed heav­ily on aquatic plants that are im­por­tant habi­tat for other in­ver­te­brates (food­stuffs for fish), shel­ter for fish, nest­ing sub­strate for fish, and aid in ero­sion con­trol. (Gun­der­son, 1995)

Con­ser­va­tion Sta­tus

This species is not af­forded any spe­cial con­ser­va­tion sta­tus.

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Com­ments

Ini­tially, the rusty cray­fish was in­tro­duced to the north­ern part of the Great Lakes re­gion by fish­er­men who used them as bait. As the pop­u­la­tion of rusty cray­fish in­creased, they were har­vested for use as fish bait and sold to bi­o­log­i­cal sup­ply com­pa­nies. This pro­vided im­pe­tus to breed­ing rusty cray­fish, and sub­se­quently, re­leas­ing them, in­ten­tion­ally or oth­er­wise, into non-na­tive wa­ters.

There is also con­cern about hy­bridiza­tion of this species with the na­tive north­ern clear­wa­ter cray­fish, Or­conectes propin­quus.

An­other com­mon name for cray­fish is craw­fish or craw­dad. (Gun­der­son, 1995; Lodge and Feder, 2001)

Con­trib­u­tors

Renee Sher­man Mul­crone (ed­i­tor).

Jan­ice Pap­pas (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Cran­dall, K., J. Fet­zner. 2003. "Or­conectes (Pro­ceri­cam­barus) rus­ti­cus" (On-line). The Cray­fish Home Page. Ac­cessed Oc­to­ber 02, 2003 at http://​crayfish.​byu.​edu/​astacidea/​cambaridae/​orconectes/​procericambarus/​orconectes_​rusticus.​html.

Crocker, D., D. Barr. 1968. Hand­book of the Cray­fishes of On­tario. Life Sci­ences Mis­cel­la­neous Pub­li­ca­tions, Royal On­tario Mu­seum. Uni­ver­sity of Toronto Press: Toronto.

Gun­der­son, J. 1995. "Min­nesota Sea Grant/rusty cray­fish fact­sheet" (On-line). Ac­cessed Jan­u­ary 23, 2002 at http://​www.​seagrant.​umn.​edu/​exotics/​rusty.​html.

Huber, R. 1999. "Lab Ex­er­cise 3-Ag­o­nis­tic Be­hav­ior in Cray­fish, An­i­mal Be­hav­ior-Bi­ol­ogy 420/543, Bowl­ing Green State Uni­ver­sity, Fall 2001" (On-line). Ac­cessed Jan­u­ary 24, 2002 at http://​caspar.​bgsu.​edu/​~courses/Ethol­ogy/Labs/Cray­fishAgon/.

Lodge, D., J. Feder. 2001. "Illi­nois-In­di­ana Sea Grant Col­lege Pro­gram" (On-line). Dis­per­sal of Ex­otic Species in the Great Lakes:Cray­fish as a Model Sys­tem for Ben­thic Species. Ac­cessed July 19, 2004 at http://​iisgcp.​org/​research/​projects/​biolresc/​res0598.​htm.

Zu­landt-Schnei­der, R., R. Huber, P. Moore. 2001. In­di­vid­ual and sta­tus recog­ni­tion in the cray­fish, Or­conectes rus­ti­cus: the ef­fects of urine re­lease on fight dy­nam­ics. Be­hav­iour, 138: 137-153.