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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