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Cambarus bartonii (Common name: Brook Crayfish)
Cambarus bartonii or the Brook Crayfish are distinctly shaped relative to crayfish in the Faxonius genus, with inflated chelae, a stubby head, and curved, club-like first pleopods. They are native to Maine and are commonly found in the northern third of the state. The streams they inhabit are often swift, cold, and rocky. This crayfish was one of the first to be documented in the state.
Faxonius immunis (Common name: Calico Crayfish)
Calico Crayfish are slender and delicate looking, with delicate patterns and a pale jagged stripe down the tail in some individuals (see image below). They are found in stagnant pools and ditches, and in slow streams with muddy bottoms, which may explain why we have found very few in the state. Some may dig terrestrial burrows. They may or may not be native to Maine.
Faxonius limosus (Common name: Spiny Cheek Crayfish)
Spiny Cheek Crayfish have numerous hepactic spines on the cheek that distinguish them from all other native crayfish species currently found in Maine; the spines are easy to feel with a fingertip on even the smallest individuals (note: the spines are not to be confused with the one cervical spine on F. virilis). They are generally smaller than F. virilis, are less aggressive, and do not trap well. Generally considered a stream crayfish, but found in Maine lakes as well, this crayfish is native and fairly common (although usually not abundant) in the southern half of the state.
Faxonius obscurus (Common name: Obscure or Allegheny Crayfish)
We have very few specimens of the Allegheny Crayfish in Maine. We believe that they are non-native to the state. Those we have records of were found in streams and lakes. If you think you have found this species we would very much like to hear about it. There is some additional information about this species at this website.
Faxonius rusticus (Common name: Rusty Crayfish)
On live Faxonius rusticus individuals, claw tips often have a jet-black band followed by red tips at the end of their claws (see image below). Many will have a rusty spot on each side of the carapace, but some populations do not. The tail is often rusty-colored in the center, but again, some populations are quite dark or indistinct. The largest individuals have blue claws. However, in areas of the country where F. rusticus are invasive, coloration can vary by lake or stream.
Rusty Crayfish are non-native to Maine. They are often aggressive towards other crayfish and are easily caught in traps. Some records of F. rusticus in Maine are from the late 1960s, but it does not appear as if this species has spread as it has in other states. See this website for more information about this species.
Faxonius virilis (Common name: Northern or Virile crayfish)
F. virilis are overall brown in color and larger individuals develop bluish chelae (claws). This crayfish is native to Maine. They are common in rocky habitats and are sometimes found in muddy bottom slow moving streams or even farm ponds. They can be locally abundant and are widespread throughout the state. In some areas of the U.S. these crayfish are considered invasive. See this website for more information on the Northern crayfish.
Procambarus acutus (Commone name: White River Crayfish)
P. acutus have distinct, elongated chelae and small bumps on their carapace. Adults are usually reddish while juveniles have distinct black stripes down their carapace and tail. They are found in mucky backwaters and in slow to moderately flowing streams and lakes. Some references suggest that this species is native to parts of Maine (southern coastal areas) but we have not seen specimens from this region. See this website for more information about this species.
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