Shortnose cisco (Coregonus reighardi) COSEWIC assessment and status report: chapter 11

Technical Summary

Coregonus reighardi

shortnose cisco – cisco à museau court

Range of Occurrence in Canada:

Lake Huron, Lake Ontario

Extent and Area Information

extent of occurrence (EO) (km²) Measured as combined areas of lakes Huron and Ontario.

  • Huron – 60,166
  • Ontario – 24,157
  • Total – 84,323

specify trend :

Decline

are there extreme fluctuations in EO (> 1 order of magnitude)?

No

area of occupancy (AO) (km²) Measured as combined areas of depths 35m-100m for lakes Huron and Ontario.

  • Huron – 28,450
  • Ontario – 6,229
  • Total – 34,679

specify trend:

Decline

are there extreme fluctuations in AO (>1 order magnitude)?

No

number of extant locations:

0

specify trend in # locations:

100% Decline

are there extreme fluctuations in # locations (>1 order of magnitude)?

No

habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat:

Stable

Population Information

generation time (average age of parents in the population) (indicate years, months, days, etc.)

5 years?

number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values):

Unknown, presumed none

total population trend:

Decline

if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period):

100%

are there extreme fluctuations in number of mature individuals (>1 order of magnitude)?

Unknown

is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., < 1 successful migrant / year)?

Yes, if consider lakes Huron and Ontario as two populations.

list each population and the number of mature individuals in each:

Presumed 0

specify trend in number of populations (decline, stable, increasing, unknown):

Decline

are there extreme fluctuations in number of populations (>1 order of magnitude)?

No

Threats

  • commercial overexploitation, introduced species?

Rescue Effect (immigration from an outside source):

None

does species exist elsewhere (in Canada or outside)?

No

status of the outside population(s)?

SX or SH

is immigration known or possible?

No

would immigrants be adapted to survive here?

Yes

is there sufficient habitat for immigrants here?

Yes?

Quantitative Analysis

No data

Existing Status

Nature Conservancy Ranks (NatueServe 2004)
  • Global – GH
  • National
    • US – NH
    • Canada – NH
  • Regional
    • US: IL – SX, IN – SX, MI – SH, NY – SX, WI – SH
    • Canada: ON – SX
  • Other
    • IUCN CR
    • AFS – E
Wild Species 2000 (Canadian Endangered Species Council 2001)
  • Canada – 0
  • Ontario – 0
COSEWIC
  • Endangered (May 2005)

Status and Reasons for Designation

Status: Endangered

Alpha-numeric Code: D1

Reasons for Designation: Endemic to three of the Great Lakes, this species was last recorded in Lake Michigan in 1982, in Lake Huron in 1985, and in Lake Ontario in 1964. Although it has presumably disappeared throughout its range, searches for this species have not been extensive enough to declare this species extinct.  The species’ apparent demise is suspected to be the result of commercial overfishing and possibly competition or predation from introduced species.

Applicability of Criteria

Criterion A (Declining Total Population): Not applicable - The species has disappeared from Lakes Michigan, Huron, and Ontario (last recorded occurrences were 1982, 1985, and 1964 respectively).  However the declines did not occur over the last 3 generations or 10 –15 years.

Criterion B (Small Distribution, and Decline or Fluctuation): Not Applicable - The current extent of occurrence and area of occupancy are presumed to be 0, as is the number of locations. However, continuing decline and extreme fluctuations do not apply for this species.

Criterion C (Small Total Population Size and Decline): Not Applicable - The number of mature individuals is already presumably 0, thus the criterion does not apply.

Criterion D (Very Small Population or Restricted Distribution): The number of mature individuals is presumably 0, so the criterion for Endangered D1 is met.

Criterion E (Quantitative Analysis): Not applicable.

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