Bering cisco (Coregonus laurettae) COSEWIC assessment and status report: chapter 13
Technical Summary
Coregonus laurettae
Range of Occurrence in Canada: Yukon Territory
Extent and Area Information
Extent of occurrence (EO)
[estimated from Figure 2]
<1000 km2
Trend in EO
Unknown
Are there extreme fluctuations in EO?
Unknown
Area of occupancy AO
[estimated from Figure 2, the river is nowhere more than 1 km wide]
<1000 km2
Trend in AO
Unknown
Are there extreme fluctuations in AO?
Unknown
Number of known or inferred current locations (see Figure 2)
1
Trend in # locations
Stable
Are there extreme fluctuations in # locations?
Unknown
In area, extent or quality of habitat?
Unknown, but probably Stable
Population Information
Generation time (average age of parents in the population)
4-6 yr
Number of mature individuals
Unknown
Total population trend
Unknown
% decline over the last/next 10 years or 3 generations
Unknown
Are there extreme fluctuations in number of mature individuals?
Unknown
Is the total population severely fragmented?
No
Trend in number of populations
Unknown
Are there extreme fluctuations in number of populations?
Unknown
List populations with number of mature individuals in each
Not Applicable
Threats (actual or imminent threats to populations or habitats)
- low to moderate, possibility of increased oil development and habitat alterations in coastal regions throughout its range
- potential for hydroelectric development on rivers where they are known to migrate
- potential for increased commercial utilization
- possible threats to the species in Canadian waters would be related to harvest and any activities which might restrict migration such as the building of power dams.
Rescue Effect: High
Status of the outside population(s)?
Asia: Unknown
USA: Secure
Is immigration known or possible?
Not known if Canadian migrants are separate stock from US population
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants here?
Probably
Quantitative Analysis
Not Applicable
Existing Status
Nature Conservancy Ranks
Global – N4
National
US – N4
Canada – N1
Regional
US – Alaska – S?
Canada – Yukon S?
COSEWIC – Data Deficient, 1990
Status and Reasons for Designation
Status: Special Concern
Alpha-numeric code: Not applicable
Reasons for Designation: This is an anadromous species that depends on barrier-free access to upstream spawning sites. In Canada, it is known only from the Yukon River. The numbers utilizing Canadian portions of the Yukon River are low compared to lower sections of the river in United States parts of the range and could be negatively impacted by hydroelectric development and expansion of commercial or subsistence fisheries, targeting other species in the river.
Applicability of Criteria
Criterion A (Declining Total Population):
Not applicable, no evidence of population decline.
Criterion B (Small Distribution, and Decline or Fluctuation):
Not applicable, although the species has a small Canadian distribution, its extent and nature of the range is uncertain, and there is no evidence of decline or fluctuation.
Criterion C (Small Total Population Size and Decline):
Not applicable, population size and trends not known. Numbers counted annually since the 1980s have been low, but counting is not consistent and the species may be easily confused with other sympatric coregonids.
Criterion D (Very Small Population or Restricted Distribution):
Not applicable. Although the species does meet the numeric thresholds under Threatened D2, i.e., restricted distribution, known only from 1 location. However, there are no immediate threats exposing the species to imminent extirpation and there is a high potential for rescue from U.S. populations.
Criterion E (Quantitative Analysis):
Not applicable, - no data.