Atlantic walrus (Odobenus rosmarus rosmarus) COSEWIC assessment and status report: chapter 14
Technical Summary
Odobenus rosmarus rosmarus
Range of Occurrence in Canada: Maritime provinces and Hudson Bay north to central and eastern high Arctic
Extent and Area Information
Extent of occurrence (EO)(km2)
~750 000 km2
Specify trend in EO
Depends on the time frame but perhaps stable
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km2)
Unknown
Specify trend in AO
Depends on the time frame but perhaps stable
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations
Many. Walruses are widespread and some are migratory.
Specify trend in #
Unknown
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat
Depends on the time frame but perhaps stable
Population Information
Generation time [(age at first reproduction + age at last reproduction) / 2]
21 y
Number of mature individuals
No complete comprehensive population survey has ever been undertaken. The number of mature animals is 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?
No
Is the total population severely fragmented?
No
Specify trend in number of populations
there is a single overall population
Are there extreme fluctuations in number of populations?
No
List populations with number of mature individuals in each
Threats (actual or imminent threats to populations or habitats)
- Hunting: The ability to sustain current removal rates is uncertain. Some portion of the population is vulnerable to hunting in Greenland waters.
- Disturbance: Walruses are sensitive to noise and habitat disturbances. Human activities on or near traditional haulout sites (uglit) can stampede herds causing mortality. Repeated disturbances can cause habitat abandonment.
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
Central West Greenland--declining;
Is immigration known or possible?
Immigration is possible but may be very slow.
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
Yes. But the reason walruses disappeared from an area may determine whether it is reoccupied.
Is rescue from outside populations likely?
Unknown
Quantitative Analysis
Not available
Current Status
COSEWIC: Eastern Arctic Population: Not at Risk, 1987;
Northwest Atlantic Population: Extirpated 1987, reconfirmed in 2000
Combined designation for all Atlantic walrus in Canada: Special Concern, 2006
Status and Reasons for Designation
Status: Special Concern
Alpha-numeric code: Not applicable
Reasons for Designation: Five populations ranging from Nova Scotia to the high Arctic are recognized for management purposes based on geographical distributions, genetics and lead isotope data. Some of the populations appear to be at greater risk than others due to over-hunting, and may be threatened. However, knowledge about population structure is insufficient to assess them separately.
The Nova Scotia-Newfoundland-Gulf of St Lawrence population was hunted to extirpation by the late 18th century. Sporadic recent sightings of individuals and small groups in the Gulf of St Lawrence and off Nova Scotia are not considered evidence of re-establishment.
The South and East Hudson Bay population is believed to number in the low hundreds, although population size and structure are poorly known. Observations from the late 1930s to the present suggest that numbers declined significantly, but the rate of decline cannot be quantified and it is not known whether the decline is continuing. The small population size suggests it may be vulnerable to disturbances and small increases in hunting effort.
The total size of the Northern Hudson Bay-Davis Strait population could be as small as 4000-6000 individuals. Its ability to sustain minimum current removals is questionable. Some portion of this population is hunted in Greenland waters.
The Foxe Basin population was estimated to be 5500 in 1989. It is unknown if current exploitation rates are sustainable.
Hunting is believed to have reduced the Baffin Bay (High Arctic) population to only a few percent of the number present in 1900. Limited information suggests the current population is small and that a portion of it continues to be hunted at unsustainable levels in the North Water area of Canada and northwest Greenland. However, satellite tracking and genetic information suggests that some animals in this population are resident in the Canadian Archipelago (west Jones Sound and Penny Strait / Lancaster Sound) and are not exposed to over-hunting.
Better information is needed on population sizes and composition, seasonal movements, vital rates, and hunting mortality. The biggest threat is over-hunting, particularly on populations that inhabit the southern and northern ends of the species’ current range. The species is near to qualifying for threatened status and requires an effective plan to manage hunting. No Management Plans are currently in place for the species. Although quotas have been set in few communities, it is not known if they are adequate to prevent over-hunting.
Applicability of Criteria
Criterion A (Declining Total Population):
Not applicable.
Criterion B (Small Distribution, and Decline or Fluctuation):
Not applicable.
Criterion C (Small Total Population Size and Decline):
Not applicable.
Criterion D (Very Small Population or Restricted Distribution):
Not applicable.
Criterion E (Quantitative Analysis):
Not applicable.
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