Cisco (fish)

The ciscoes (or ciscos) are salmonid fish that differ from other members of the genus Coregonus 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.

In previous taxonomic classifications, the ciscoes have been identified as a subgenus Leucichthys of the genus Coregonus. Based on molecular data this is not a natural classification however, as the ciscoes are polyphyletic, comprising two different lineages within the freshwater whitefishes.