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COSEWIC Assessment and Update Status Report on the Bowhead Whale in Canada

Technical Summary - Hudson Bay-Foxe Basin population

Balaena mysticetus

Bowhead Whale - Hudson Bay-Foxe Basin population

Baleine boréale

Range of Occurrence in Canada: Hudson Bay, Foxe Basin, Hudson Strait


Extent and Area Information

Extent of occurrence (EO) (km2)
For calculation see Table 1
approx. 350 000 km2
Specify trend in EOstable
Are there extreme fluctuations in EO?No
Area of occupancy (AO) (km2)
For calculation see Table 1
approx. 250 000 km2
Specify trend in AOstable
Are there extreme fluctuations in AO?seasonal
Number of known or inferred current locationsnot applicable
Specify trend in #not applicable
Are there extreme fluctuations in number of locations?not applicable
Specify trend in area, extent or quality of habitatunknown


Population Information

Generation time (average age of parents in the population)60 yearsa
Number of mature individuals< 1000
Total population trendpossibly increasing
% decline over the last/next 10 years or 3 generations-
Are there extreme fluctuations in number of mature individuals?unlikely
Is the total population severely fragmented?No
Specify trend in number of populationsnot applicable
Are there extreme fluctuations in number of populations?not applicable
List populations with number of mature individuals in each:not applicable

a Assuming that the average age of maturity is 25 years, and that the average bowhead lives to 120 years.


Threats (actual or imminent threats to populations or habitats)

Potential threats are man-made noise, climate change, and illegal hunting.


Rescue Effect (immigration from an outside source)

Status of outside population(s)?
Alaska/western Canadian Arctic; eastern Canadian Arctic/West Greenland
Endangered
Is immigration known or possible?possible
Would immigrants be adapted to survive in Canada?yes
Is there sufficient habitat for immigrants in Canada?yes
Is rescue from outside populations likely?uncertain


Current Status

COSEWIC: Threatened (May 2005)


Status and Reasons for Designation

Status:
Threatened
Alpha-numeric code:
D1
Reasons for Designation:
The population was severely reduced by commercial whaling between 1860 and 1915. Recent population estimates are uncertain, but indicate that there could be as few as 300 mature individuals, of which only half might be females. Threats to this small population include illegal hunting and increased vulnerability to killer whale predation as a result of reduced ice coverage.


Applicability of Criteria

Criterion A (Declining Total Population):
Criterion not met. The population is believed to have numbered at least 500 animals in the mid-1800s. Whaling reduced the population in the late 19th C, to the point that it was difficult for the commercial whalers to find a single whale. There is considerable uncertainty in the numbers of whales present in 2003. The 2003 partial estimate has extremely wide confidence limits and is believed to be biased upwards (mean = 1026, 95% CI = 338-3124 individuals). A precautionary approach is to therefore apply the lower confidence limit, which suggests the current population is lower than pre-exploitation levels--but the extent of the decline cannot be ascertained.
Criterion B (Small Distribution, and Decline or Fluctuation):
Criterion not met. EO and AO are large, and there is no evidence of fluctuations.
Criterion C (Small Total Population Size and Decline):
Criterion not met. Number of mature individuals is <2500, but there is no evidence of continuing decline.
Criterion D (Very Small Population or Restricted Distribution):
Meets Threatened D1. Number of mature individuals <1000. There is considerable uncertainty about population size due to uncertainties associated with the correction factor applied to the 2003 survey and the portion of the population that was outside the surveyed area. The best partial estimate in 2003 was 1026 individuals (95% CI = 338-3124) and is believed to be overestimated by 20%. Assuming a total population of 800 of which 59% are immature, there may be as few as 300 mature individuals and only 150 mature females. However, there could be even fewer mature females in the population if the lower confidence limit (338) more accurately reflects the total numbers present in 2003.
Criterion E (Quantitative Analysis):
Not available.

 

Technical Summary - Davis Strait-Baffin Bay population

Balaena mysticetus

Bowhead Whale - Davis Strait-Baffin Bay population

Baleine boréale

Range of Occurrence in Canada: Davis Strait, Baffin Bay and Lancaster Sound


Extent and Area Information

Extent of occurrence (EO) (km2)
For calculation see Table 2
approx. 800 000 km2
Specify trend in EOstable
Are there extreme fluctuations in EO?No
Area of occupancy (AO) (km2)
For calculation see Table 2
approx. 300 000 km2
Specify trend in AOstable
Are there extreme fluctuations in AO?seasonal
Number of known or inferred current locationsnot applicable
Specify trend in #not applicable
Are there extreme fluctuations in number of locations?not applicable
Specify trend in area, extent or quality of habitatunknown


Population Information

Generation time (average age of parents in the population)60 yearsa
Number of mature individuals< 1000
Total population trendpossibly increasing
% decline over the last/next 10 years or 3 generations-
Are there extreme fluctuations in number of mature individuals?unlikely
Is the total population severely fragmented?No
Specify trend in number of populationsnot applicable
Are there extreme fluctuations in number of populations?not applicable
List populations with number of mature individuals in each:not applicable

a Assuming that the average age of maturity is 25 years, and that the average bowhead lives to 120 years.


Threats (actual or imminent threats to populations or habitats)

Potential threats are man-made noise, climate change, and illegal hunting.


Rescue Effect (immigration from an outside source)

Status of outside population(s)?
USA:
Endangered
Is immigration known or possible?possible
Would immigrants be adapted to survive in Canada?Yes
Is there sufficient habitat for immigrants in Canada?Yes
Is rescue from outside populations likely?No


Current Status

COSEWIC: Threatened (May 2005)


Status and Reasons for Designation

Status:
Threatened
Alpha-numeric code:
Meets criterion for Endangered, A1b, but assessed as Threatened, A1b, because commercial whaling--the primary cause of population reduction--has ceased.
Reasons for Designation:
The population numbered at least 11 000 animals when commercial whaling began. Whaling reduced the population to less than 30% of its former abundance. Recent estimates indicate that the population is growing and is larger than previously thought, but is likely to still number fewer than 3000 individuals of all ages. The population qualifies for endangered, but is not judged to be in imminent danger of extinction. Threats include illegal hunting and increased vulnerability to killer whale predation as a result of reduced ice coverage.


Applicability of Criteria

Criterion A (Declining Total Population):
Meets Endangered A1b. The population numbered at least 11 000 animals in the early 1700s. Commercial whaling reduced the population to less than 30% of its former abundance. Recent partial population estimates indicate that there may be between 1539 (95% CI = 631-3770) and 1944 individuals (95% CI = 797-4762). This suggests a population that could number less than 3000 individuals of all ages. Even the most optimistic population estimate for all of the eastern Canadian Arctic is less than 50% of pre-exploitation numbers (i.e., 5016: 95% CI = 2611-9633 for Davis Strait-Baffin Bay population and Hudson Bay population).
Criterion B (Small Distribution, and Decline or Fluctuation):
Criterion not met. EO and AO are large.
Criterion C (Small Total Population Size and Decline):
Criterion not met. Population is small, but there is no evidence of a continuing decline.
Criterion D (Very Small Population or Restricted Distribution):
Meets Threatened D1. Number of mature individuals <1000. There is considerable uncertainty about population size due to uncertainties associated with the correction factors applied to the 2003 survey data, and the unknown portion of the population that summered outside the survey area. The best partial estimate in 2003 was between 1539 individuals (95% CI = 631-3770) and 1944 individuals (95% CI = 797-4762), of which 41% could be considered mature individuals.
Criterion E (Quantitative Analysis):
Not available.

 

Technical Summary - Bering-Chukchi-Beaufort population

Balaena mysticetus

Bowhead Whale - Bering-Chukchi-Beaufort population

Baleine boréale

Range of Occurrence in Canada: Canadian Beaufort Sea and Amundsen Gulf


Extent and Area Information

Extent of occurrence (EO) (km2)
Calculation found in Distribution Section, Canadian range, Bering-Chukchi-Beaufort population.
approx. 200 000 km2
Specify trend in EOstable
Are there extreme fluctuations in EO?No
Area of occupancy (AO) (km2)
Calculation found in Distribution Section, Canadian range, Bering-Chukchi-Beaufort population.
approx. 90 000 km2
Specify trend in AOstable
Are there extreme fluctuations in AO?seasonal
Number of known or inferred current locationsnot applicable
Specify trend in #not applicable
Are there extreme fluctuations in number of locations?not applicable
Specify trend in area, extent or quality of habitatunknown


Population Information

Generation time (average age of parents in the population)60 yearsa
Number of mature individuals4118 bowheads
(41.1% of population)
Total population trendincreasing
% decline over the last/next 10 years or 3 generations-
Are there extreme fluctuations in number of mature individuals?No
Is the total population severely fragmented?No
Specify trend in number of populationsnot applicable
Are there extreme fluctuations in number of populations?not applicable
List populations with number of mature individuals in each:not applicable

a Assuming that the average age of maturity is 25 years, and that the average bowhead lives to 120 years.


Threats (actual or imminent threats to populations or habitats)

Potential threats are climate change, man-made noise, and oil spills.


Rescue Effect (immigration from an outside source)

Status of outside population(s)?
USA:
Endangered
Is immigration known or possible?possible
Would immigrants be adapted to survive in Canada?Yes
Is there sufficient habitat for immigrants in Canada?Yes
Is rescue from outside populations likely?No


Current Status

COSEWIC: Special Concern (May 2005)


Status and Reasons for Designation

Status:
Special Concern
Alpha-numeric code:
Not applicable
Reasons for Designation:
This population was hunted to low levels during commercial whaling. Although supporting a regulated hunt, it is recovering and is currently at about 50% of its historical population size. The population is not yet secure and is potentially negatively affected by climate change, and by oil and gas development.


Applicability of Criteria

Criterion A (Declining Total Population):
Threatened A1 is almost met. The last census in 2001 suggested that the population was still reduced from historical levels by almost 50%. However, the population has been increasing for at least the last decade, and the hunts in Russia, Alaska, and Canada are regulated to allow for continued recovery.
Criterion B (Small Distribution, and Decline or Fluctuation):
The population is widely distributed, and there is no evidence of change in EO and AO.
Criterion C (Small Total Population Size and Decline):
Number of mature individuals is <10 000, but there is no evidence of continuing decline.
Criterion D (Very Small Population or Restricted Distribution):
Number of mature individuals >1000 and distribution is not restricted.
Criterion E (Quantitative Analysis):
Not available.