Plants and Animals
Coregonus zenithicus Shortjaw cisco
Shortjaw cisco usually have a lower jaw that is shorter than the upper jaw. They have no symphyseal knob on jaw and upper jaw often reaches to the middle of pupil. This cisco has 32 to 46 gill rakers in Lake Superior and between 34 and 44 in Lakes Huron and Michigan.
Status and Rank
State Status: T - Threatened (legally protected)
Global Rank: G3 - Vulnerable
State Rank: S2 - Imperiled
|County||Number of Occurrences||Year Last Observed|
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
The shortjaw cisco is a deep, cold water species that spawns at depths of 36 to 73 m over clay substrates.
Specific Habitat Needs
Clay substrates needed in: Great lake, pelagic, midwater;
Deep water, 18-183 m in depth needed in: Great lake, pelagic, midwater;
Natural Community Types
- Great lake, pelagic, midwater
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Exotic species are a threat to this species. Manage introduced species to limit competition (e.g. alewife, rainbow smelt) or food web disruption (e.g. loss of Diporeia). Other threats include: habitat loss, contaminants, itrogressive hybridization with bloater (Houston 1988).
Spawning from fourth week of November to second week of December
Trawls should be 55-71m in summer, 73-90m in winter (Becker 1983)
Survey Period: From first week of November to fourth week of October
- Murphy, B.R. and D.W. Willis, eds. 1996. Fisheries Techniques, 2nd ed. American Fisheries Society, Bethesda. 732pp.
- Bailey, R.M., W.C. Latta, and G.R. Smith. 2004. An Atlas of Michigan Fishes. Museum of Zoology, University of Michigan, No. 192, Ann Arbor. 215p.
- Becker, G.C. 1983. Fishes of Wisconsin. The University of Wisconsin Press, Madison. 1052 pp.
- Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
- Houston, J.J. 1988. Status of the shortjaw cisco, Coregonus zenithicus, in Canada. Canadian Field-Naturalist 102(1):97-102.
- Page, L. M. and B.M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston. 432pp.
- Scott, W.B. and E.J. Crossman. 1973. Freshwater fishes of Canada. Bulletin 184, Fisheries Research Board of Canada, Ottawa. 966pp.