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Water chestnut (Trapa natans)
Photo credit: © Aleta Karstad/Flickr

Big Water Crayfish

(Cambarus robustus)

Report this Species!

Note: The Big Water Crayfish is native to portions of Pennsylvania.

View a map of this species' native range within Pennsylvania.

If you believe you have found this species in Pennsylvania, please report your findings to iMapInvasives by submitting an observation record.

Species at a Glance

The big water crayfish is a large, non-burrowing crayfish that lives on rocky substrates in fast moving streams and some lakes (Berrill and Chenoweth 1982; Hamr and Berrill 1984). Breeding occurs in the late summer (Hamr and Berrill 1984). 


The overall body color is greenish-brown. This species possesses large, strong chelae and a long, narrow rostrum (Guarino et al. 2012; Massachusetts Division of Fisheries and Wildlife 2015). The corners of the rostrum are rounded and the chelae have two rows of bumps on the margin of the palm (Guarino et al. 2012).


Size:  Up to 6 cm carapace length (Hamr and Berrill 1985).


Most likely introduced by accidental bait release.


Established in Connecticut and New York; the status is unknown in Vermont (Guarino et al. 2012).


Unknown. However, Guiasu and Dunham (1999) found that, in its native range, C. robustus exhibited dominant aggressive behavior towards Cambarus bartonii bartonii during direct encounters.


Information for this species profile comes from the USGS NAS Big Water Crayfish fact sheet.

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