The
ciscoes (or
ciscos) are
salmonid fish of the genus
Coregonus that differ from other members of the genus in having upper and lower jaws of approximately equal length and high
gill raker counts. These species have been the focus of much study recently, as researchers have sought to determine the relationships among species that appear to have evolved very recently. The term
cisco is also specifically used of the North American species
Coregonus artedi, also known as lake herring.