ÿþ<HTML> <HEAD> <title>Ontario Crayfish Identification Guide - Orconectes immunis</title> <meta name="keywords" content="Orconectes immunis, Papershell Crayfish, papershell crayfish, crayfish identification, Crayfish identification, crayfish species identification, ontario crayfish identification"> </HEAD> <BODY BGCOLOR="#339999" VLINK="#811F78" ALINK="42426F"> <BASEFONT SIZE=1> <TABLE BORDER=3 CELLPADDING=40> <TR> <TD><TABLE ALIGN=LEFT CELLPADDING=150> <TR ALIGN=CENTER> <TD VALIGN=TOP ALIGN=LEFT BGCOLOR="#FFFFFF"><P><FONT FACE="ARIAL,SWISS"> <IMG SRC="oimmunis.jpg" WIDTH=496 HEIGHT=252 ALT="[Orconectes immunis]" ALIGN=TOP > <FONT FACE="COMIC SANS MS"> <H1 ALIGN=CENTER>Orconectes immunis</H1> <H2 ALIGN=CENTER>Papershell Crayfish</H2> </ALIGN=CENTER> <ALIGN=LEFT> <FONT SIZE=2> <H3>DESCRIPTION</H3> The Papershell Crayfish is also commonly known as the Calico Crayfish; ecrivisse-calicot. It is a small to medium- sized crayfish that is slender and fragile looking. It is distinguished from other orconectids by notch at base of inner side of dactyl of chela. Colouring is olive- green to brown with characteristic dorsal mottled pattern and no colour bands on tips of chela. <H3>HABITAT</H3> Found in slow moving streams, ponds and lakes, marshes and roadside ditches. It can construct deep burrows and as a result is able to survive in temporary waters. <H3>DISTRBUTION</H3> Canada/Ontario<BR><BR> Canada/Ontario Ð The documented Canadian range of this species appears to center on southern Ontario (Crocker and Barr, 1968; Berrill, 1978; David et al., 1997) but it has also been found in northern Ontario (Crab Lake, Sudbury District and Snake Bay in Lake of the Woods) and Quebec (parc de al Verendrye and the Laurentides region), as well as in Manitoba (Red River drainage south of Winnipeg) (Popham and Hancox, 1970; Dube and Renaud, 1994; Schueler unpublished). It is suspected that the Quebec records may be a result of introductions by New York anglers (Dube pers. comm.) but it is also possible that the species may have a much broader (undocumented) distribution in Canada. <BR><BR>North America<BR>This species range is in the northeast and midwest of North America. It is found in Quebec, Ontario, Manitoba, Vermont*, New York, New Hampshire, Maine*, Rhode Island*, Massachusetts*, Connecticut*, Michigan, Ohio, Wisconsin, Illinois, Kentucky, Tennessee, Alabama, Mississippi, Indian, Minnesota, Iowa, Missouri, Arkansas, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Montana, Wyoming and Colorado (Hobbs, 1989; Taylor et al., 1996) (*indicates suspected/known introduction). HABITAT AND ECOLOGY: The substrate in the habitats of this species is generally soft mud or clay with abundant aquatic vegetation(Crocker and Barr, 1968; Berrill, 1978). This species is thought to be tolerant of low oxygen concentrations often associated with certain types of pollution and habitat alteration (Page, 1985). It can also travel across dry ground, especially in wet weather and is thus able to move from pond to pond (Crocker and Barr, 1968). Burrows are mostly simple but can be more complex and capped with chimneys. This makes its presence easily confused with the occurrence of the other two burrowing species (the Chimney Crayfish and the Devil Crawfish). Like the other burrowing species, the Papershell Crayfish has a preference for soft substrates and a low ability to hold station in currents faster than 26 cm/sec (10.1 in./sec), the lowest slip-speed value of Canadian crayfishes tested (Maude and Williams, 1983). These factors are likely to exclude it from colonizing faster flowing rocky streams. In Ontario, this species occurs together with the Appalachian Brook Crayfish, the Chimney Crayfish, the Northern Clearwater Crayfish the Rusty Crayfish, the Virile Crayfish and the Obscure Crayfish (Berrill, 1978; David et al., 1996; Hamr unpublished data). <H3>ECOLOGY</H3> This species is most common in fast flowing, rocky areas which remain cool and well oxygenated in the summer(Crocker and Barr, 1968; Bousfield, 1969; Berrill, 1978; Hamr and Berrill, 1985; Guiasu et al., 1996). Shelters usually consist of excavations in gravel and sand under larger rocks (Crocker and Barr, 1968; Hamr, 1983). The species shows a remarkable ability to penetrate deep into the substrate. Excavations can go as deep as 1 m throughout several layers of rock and gravel (Hamr, 1983). On the Canadian Shield in Ontario, this species has been found in deep, high elevation lakes spanning abroad range of pH values (5.0->7.0)(David et al., 1994). In Canada, this species has been found together with Robust Crayfish, Northern Clearwater Crayfish, Virile Crayfish, Obscure Crayfish, Papershell Crayfish and Rusty Crayfish (Berrill, 1978; Hamr, 1983; David et al., 1997). In laboratory studies Cambarus bartonii was found to be clearly more aggressive than Virile Crayfish and Northern Clearwater Crayfish but less aggressive than Robust Crayfish (Guiasu and Dunham, 1997). <H3>LIFE HISTORY</H3> Little is known about the life history of Canadian populations of the Papershell Crayfish. In Chemong Lake, southern Ontario, ovigerous (mature) females ranged in CPL from 32-44 mm (1.25- 1.72 in.) while Form I (mature) males ranged from 30-48 mm (1.17-1.87 in.) CPL (Berrill, 1978). Few females carrying eggs were found in late summer and autumn suggesting that some females may extrude eggs in the fall and carry them over winter (Berrill, 1978). Hatching probably occurs in May and Ontario (Crocker and Barr, 1968). Form I males were found in April, July and August (Crocker and Barr, 1968) and Form II in June. Hatching occurs from April to early June and young reach CPLs of 13-29 mm (0.51- 1.13 in.) by the end of the first summer. Some become mature at this time but most do not reach maturity until the following spring. Males are in Form I from July to June and in Form II in May and June (Crocker and Barr, 1968). The average life span is 2-3 years and maximum recorded size is 49 mm (1.91 in.) CPL (Page, 1985). <H3>CONSERVATION STATUS</H3> Like the other burrowing species, the Papershell Crayfish is found in many habitats which are vulnerable and subject to pressure from agriculture and urbanization. However, its Canadian range is somewhat broader than those of the other two "burrowing" species due to the fact that it is not an obligate burrower and has a broader ecological niche and distribution. The physiological tolerance of the Papershell Crayfish to both organic pollution and low oxygen requirements allows this species to occupy habitats that would be unsuitable for less tolerant crayfish species. As such, this species should therefore be considered "Currently Stable''. <BR><BR><BR><I>(Used by permission: text by Premek Hamr, modified from "Baitfish of North America"2007<BR>painting by Aleta Karstad) </I> <BR> </TD> </TR> </FONT SIZE> </TD> </TR> </TABLE> </BODY> <FONT FACE="COMIC SANS MS"> <FONT SIZE=+2> <CENTER> <BR><BR> <A HREF="craydentpage.htm"><B>return to Identification Guide</B></A> <BR><BR> <A HREF="index.htm"><B>home</B></A> <BR><BR> </HTML>