Observations of claw differences in an invasive crayfish (Orconectes virilis)

The Northern Crayfish (Orconectes virilis) is a relatively new invasive species to Calgary, Alberta Canada. We observed unique morphological characteristics concerning the claws (cheliped) of four (3 males and 1 female) out of 31 crayfish captured using a sweep sampling method from a creek in Calgary, Canada. These specimens exhibited a notable difference in claw size between the right and left claws. Differences in claw sizes can be attributed to an ongoing process of regeneration due to loss of the crayfish’s cheliped.