Cisco (Coregonus artedi) is the only native fish from the salmon family found in Indiana waters outside of Lake Michigan. It is a coldwater species that inhabits waters as far north as Canada and as far south as the upper Midwestern United States. Cisco are small and slender, silver-colored fish. They feed primarily on zooplankton, a diverse group of microscopic animals that live in aquatic environments. In Indiana, cisco grow to 7 inches by age 2, 12 inches by age 4, 15 inches by age 6, and they have been known to reach 19 inches at around 10 years of age.
The glacial lakes of northern Indiana represent the southernmost extent of cisco’s range in North America. Glacial lakes are lakes formed by receding glaciers and water from melting glaciers. Only about 24% of Indiana lakes, primarily in the northern glacial lakes region, provide late-summer coldwater habitat (≤ 68°F and ≥ 3.0 mg/L dissolved oxygen) suitable for cisco.
The number of lakes supporting cisco populations in Indiana has declined precipitously since 1955 as a result of coldwater habitat loss at many lakes. Failing Lake (Steuben County), Indiana Lake (Elkhart County), North Twin and South Twin lakes (LaGrange County), Lake Gage (Steuben County), Eve Lake (LaGrange County), and Crooked Lake (Noble/Whitley counties) are the only remaining Indiana lakes containing cisco.
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The Division of Fish & Wildlife (DFW) has taken several steps to conserve cisco populations over the last half century. The DFW has attempted to reintroduce cisco at two coldwater lakes, including Gilbert Lake (Noble County) in 1979 and Green Lake (Steuben County) in the early 1990s. Both of these attempts to reintroduce cisco failed to establish self-sustaining populations.
Gill netting during the fall (Nov.-Dec.) for cisco was once the preferred method anglers used to capture cisco. Early gill netting regulations required anglers to purchase a cisco license and restricted gill net mesh sizes. The harvest of cisco using gill nets was discontinued in the late 1970s to protect declining cisco populations.
Today, cisco are listed as a Species of Greatest Conservation Need and are classified as a Species of Special Concern in Indiana. The 2015 State Wildlife Action Plan (SWAP) used the lake catchments of known cisco populations to define six Conservation Opportunity Areas (COAs) in northern Indiana to focus the conservation community’s efforts on coldwater habitat protection and restoration. The long-term protection of Indiana’s remaining cisco populations will rely largely on collaborative efforts to preserve coldwater habitat through the application of best management practices (BMPs) that reduce the quantity of nutrients entering Indiana’s waterways.
Matthew D. Linn
Fisheries Research Biologist
Indiana Department of Natural Resources
1353 South Governors Drive
Columbia City, IN 46725