by Dan O’Keefe, Michigan Sea Grant

The cisco (aka lake herring, Coregonus artedi) was one of the most abundant fish in Lake Michigan before unregulated commercial fishing, invasive species, and habitat degradation took their toll. By the mid-1960s, cisco were nearly wiped out. Most of their deepwater cousins also disappeared from the lake. Six out of seven native deepwater ciscoes are no longer found in Lake Michigan. The only deepwater cisco that still survives in Lake Michigan is the Bloater (Coregonus hoyi).

To confuse matters, not all cisco (Coregonus artedi) look and act the same. According to a recent monograph, there are different “minor forms” of the cisco species. Body depth and mouth shape vary somewhat from one minor form to the next, but the reasons for this variability are poorly understood.

Michigan Sea Grant/Univ. of Michigan