Sei whale (Balaenoptera borealis) COSEWIC assessment and status report: chapter 12

Technical Summary

Balaenoptera borealis

Sei whale (Pacific Population): Rorqual boréal

Range of Occurrence in Canada:
Eastern North Pacific

Extent and Area information

Extreme fluctuations in EO and AO suggested because of sporadic, unpredictable occurrence over large areas.

extent of occurrence (EO)(km²)
> 10,000 km²
specify trend (decline, stable, increasing, unknown):
Unknown
are there extreme fluctuations in EO (> 1 order of magnitude)?
Yes
area of occupancy (AO) (km²)
> 10,000 km²
specify trend (decline, stable, increasing, unknown):
Unknown
are there extreme fluctuations in AO (> 1 order magnitude)?
Yes

number of extant locations

specify trend in # locations (decline, stable, increasing, unknown):
Unknown
are there extreme fluctuations in # locations (>1 order of magnitude)?
Yes
habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat:
Habitat quality may be decreasing.

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.):
20 to 40 years
number of mature individuals (capable of reproduction) in the Pacific population (or, specify a range of plausible values):
Unknown
total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals:
Unknown
if decline, % decline over the last/next 10 years or 3 genera-
tions, whichever is greater (or specify if for shorter time period):
Unknown
are there extreme fluctuations in number of mature individuals
(> 1 order of magnitude)?
No
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)?
Unknown
list each population and the number of mature individuals in each:
n/a
specify trend in number of populations (decline, stable, increasing, unknown):
n/a
are there extreme fluctuations in number of populations
(>1 order of magnitude)?
Yes

Threats (actual or imminent threats to populations or habitats)

  • Interactions with vessel traffic
  • Interactions with mineral exploration and extraction
  • Noise pollution
  • Chemical pollution
  • Competition

Rescue Effect (immigration from an outside source)

Low

does species exist elsewhere (in Canada or outside)?
Yes
status of the outside population(s)?
Unknown
is immigration known or possible?
Yes, possible
would immigrants be adapted to survive here?
Likely
is there sufficient habitat for immigrants here?
Likely

Quantitative Analysis

None available

Balaenoptera borealis

Sei whale (Atlantic Population): Rorqual boréal

Range of Occurrence in Canada:
Northwest Atlantic Ocean

Extent and Area information

Extreme fluctuations in EO and AO suggested because of sporadic, unpredictable occurrence over large areas.

extent of occurrence (EO) (km²)
> 10,000 km²
specify trend (decline, stable, increasing, unknown):
Unknown
are there extreme fluctuations in EO (> 1 order of magnitude)?
Yes
area of occupancy (AO) (km²)
> 10,000 km²
specify trend (decline, stable, increasing, unknown):
Unknown
are there extreme fluctuations in AO (> 1 order magnitude)?
Yes
number of extant locations:
Unknown

specify trend in # locations (decline, stable, increasing, unknown)

are there extreme fluctuations in # locations (>1 order of magnitude)?
Yes
habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat:
Habitat quality may be decreasing.

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.):
20 to 40 years
number of mature individuals (capable of reproduction) in the Atlantic population (or, specify a range of plausible values):
Hundreds to several thousand
total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals:
Unknown
if decline, % decline over the last/next 10 years or 3 gene-
rations, whichever is greater (or specify if for shorter time period):
Unknown
are there extreme fluctuations in number of mature individuals
(> 1 order of magnitude)?
No
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)?
Unknown

list each population and the number of mature individuals in each:

  • Nova Scotia Stock
  • Labrador Stock (putative);
  • Populations unknown
specify trend in number of populations (decline, stable, increasing, unknown):
n/a
are there extreme fluctuations in number of populations
(>1 order of magnitude)?
No

Threats (actual or imminent threats to populations or habitats)

  • Interactions with vessel traffic
  • Interactions with mineral exploration and extraction
  • Noise pollution
  • Chemical pollution
  • Competition

Rescue Effect (immigration from an outside source)

Low

does species exist elsewhere (in Canada or outside)?
Yes
status of the outside population(s)?
Unknown
is immigration known or possible?
Yes, possible
would immigrants be adapted to survive here?
Likely
is there sufficient habitat for immigrants here?
Likely

Quantitative Analysis

None available

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