Knowledge Bank

Field studies during the past five years indicate that the crayfish Orconectes obscurus (Hagen) is not an endangered species. However, the introduction of 0. rusticus (Hagen) into Sunfish Creek has almost eliminated 0. obscurus from this watershed. Orconectes sloanii Bundy is considered threatened because it has not been collected recently from many localities where it was found formerly. Additional information is needed to determine the status of four other taxa. Orconectes virilis (Hagen) occurs only in the East Branch of the Chagrin River. This stream should be investigated to determine if 0. rusticus is eliminating 0. virilis. Orconectes propinquus (Girard) apparently has been extirpated from the Maumee, Portage, Sandusky, and Rocky rivers. The status of this species in the Grand and Ashtabula rivers and Conneaut Creek is unknown. Orconectes sanbornii erismophorous Hobbs & Fitzpatrick has been collected from only one locality in the lower Scioto River basin. The taxonomic status and distribution of what has been called 0. juvenilis (Hagen) in Ohio needs special attention. This species is either 0. spinosus (Bundy) or a closely related undescribed species that has been collected, usually in small numbers, from the Little Miami River, lower Scioto River, and Eagle and Pine creeks in southern Ohio.