Lake whitefish (Coregonus clupeaformis) in Lake Simcoe COSEWIC assessment and status report: chapter 11
Technical Summary
Coregonus clupeaformis
Lake whitefish, Lake Simcoe population – Grand corégone, population du lac Simcoe
Range of Occurrence in Canada:
Ontario
Extent and Area information
extent of occurrence (EO) [see Distribution]:
725 km²
trend:
Stable
are there extreme fluctuations in EO?
No
area of occupancy (AO) [less than EO as the species is not found throughout the lake]:
<725 km²
trend:
Stable
are there extreme fluctuations in AO?
No
number of extant locations:
1
trend in # locations:
Stable
are there extreme fluctuations in # locations?
No
habitat trend:
Decline
Population Information
generation time (average age of parents in the population):
Wild fish - <30 years Stocked fish - 10 years
number of mature individuals (capable of reproduction) in the Canadian population
Estimated to be in the area of 200,000 including stocked fish, which probably represent 90% of whitefish in the lake: Unknown
total population trend:
Wild fish declining
if decline, % decline over the last/next 10 years or 3 generations, whichever is
15 year decline of 60% for wild fish
are there extreme fluctuations in number of mature individuals?
No
is the total population severely fragmented?
No
list each population and the number of mature individuals in each?
Not Applicable
trend in number of populations:
Not Applicable
are there extreme fluctuations in number of populations?
Not Applicable
Threats (actual or imminent threats to populations or habitats)
- Lack of natural reproduction resulting from habitat loss due to cultural eutrophication and its effects on spawning and hypolimnetic habitat
- Inter-specific competition with introduced exotics i.e., rainbow smelt
- Potential of negative impact from introduction of zebra mussels and spiny waterfleas
Rescue Effect (immigration from an outside source)
does species exist elsewhere (in Canada or outside)?
Not the Lake Simcoe strain
status of the outside population(s)?
Good
is immigration known or possible?
No
Would immigrants be adapted to survive here?
Probably
is there sufficient habitat for immigrants here?
No
Quantitative Analysis
Not Done
Existing Status
Nature Conservancy Ranks (Natureserve 2004)
- Global – T2
- National
- US – N/A
- Canada NNR
- Regional
- US – N/A
- Canada – ON: SNR
- Wild Species 2000 (Canadian Endangered Species Council 2001) – NR
- COSEWIC – Data Deficient (May 2005)
Status and Reasons for DesignationFootnote1
Status: Data Deficient
Alpha-numeric code: Not Applicable
Reasons for Designation: Although this population is on its way to extirpation, there is inconclusive evidence regarding its distinctiveness and the best evidence available at this time is insufficient to resolve the species’ eligibility for assessment.
Applicability of Criteria
Criterion A (Declining Total Population): The wild component of the population has severely declined and remains depressed (A2b), habitat quality and quantity generally is degraded (A2c), exploitation continues and appears to be increasing (A2d), and exotics continue to threaten the integrity of both the ecosystem and the population (A2e); recovery may be further impacted by hatchery propagation procedures. The wild component qualifies for Endangered; the total population (wild+stocked) qualifies for Threatened; however, there is insufficient evidence to establish eligibility.
Criterion B (Small Distribution, and Decline or Fluctuation): One lake containing one population with a limited or unknown number of stocks present in a continued depressed state. The number of mature wild individuals has declined, appears to consist mostly of very old fish from recruitment events >30 years ago, thus will decline in future as these individuals die from either natural or fishing causes (B2a,b(v)). Although attempts at reversing habitat degradation have occurred and some success has been realized, rehabilitation to levels necessary for population recovery is unlikely; however, there is insufficient evidence to establish eligibility.
Criterion C (Small Total Population Size and Decline): No information regarding actual abundance is available for wild fish, but it is likely quite low relative to what should be present in a lake this size.
Criterion D (Very Small Population or Restricted Distribution): Criterion not met; however, there is insufficient evidence to establish eligibility.
Criterion E (Quantitative Analysis): Data not available; however, there is insufficient evidence to establish eligibility.
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