Coregonus zenithicus
Shortjaw cisco

Key Characteristics

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
  • State Rank: S2
  • Global Rank: G3

Occurrences

County NameNumber of OccurrencesYear Last Observed
Alcona21980
Alger12001
Allegan22001
Baraga22001
Berrien11994
Chippewa22000
Emmet11998
Houghton12001
Iosco11982
Keweenaw72001
Manistee12001
Marquette42001
Ontonagon11999
Ottawa12001
Schoolcraft11999
Van Buren11994
Distribution map for Coregonus zenithicus

Updated 1/31/2017. 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.

Habitat

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

Methodology

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.

Management

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).

Active Period

Spawning from fourth week of November to second week of December

Survey Methods

Trawls should be 55-71m in summer, 73-90m in winter (Becker 1983)

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed May 27, 2017]

References

Survey References

Technical References

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