The Orconectes limosus is a crayfish in the family Cambaridae.

Comes from the the east coast of North America, but has also been introduced in 1890 to Europe.

The Sihlsee has a big population of this crayfish – to the chagrin of the local crayfish. The Orconectes limosus is the carrier of the crayfish plague (Aphanomyces astaci), which is a water mold that infects local crayfish. Orconectes limosus is self immune against this disease deadly.

This shell was found in the Sihlsee, Schwyz, Switzerland.