Grey whale (Eschrichtius robustus) COSEWIC assessment and status report: chapter 13
Technical summary
Grey whale
Eastern North Pacific population
Baleine grise
Range of Occurrence in Canada: Coastal waters of British Columbia (BC) and southern Beaufort Sea
Extent and area information
(Coastal waters of British Columbia and shallow sections of southern Beaufort Sea between Alaskan border and Cape Bathurst)
(Coastal waters of British Columbia)
Population information
BC summer resident community: 110
(numbers represent 60% of population estimate)
BC summer resident community: stable or increasing
1998–2002: 10% annual decrease (calculated from population estimates, see page 15)
post-2002: trend unknown but probably stable or increasing (based on mortality and calf production)
Threats (actual or imminent threats to populations or habitats)
- Habitat loss or degradation (e.g., development of breeding lagoons in Mexico, oil and gas exploration along migratory pathways and on feeding grounds in US and Canadian waters,
- Mortality from entanglement in fishing gear and marine debris
- Mortality from boat collisions
Rescue effect (immigration from an outside source)
Quantitative Analysis
None
Other Status
COSEWIC: Not at Risk, April 1987.
Status and reasons for designation
Reasons for Designation: Grey whales migrate each year from their winter calving grounds in Mexico to their summer feeding areas in northern Alaska, Russia and Canada. Most of the population passes along the BC coastline, and some individuals repeatedly spend the entire summer feeding in BC (about 80). The population increased by 2.5% per year following the cessation of whaling, and peaked, within the range of pre-exploitation estimates, at about 27 000 animals in 1998. The extent of recovery of the summer resident group is unknown. However, over one-third of the population died from 1998 to 2002 (possibly due to a lack of food in Alaska). Birth rates, survival rates and other indicators suggest that the decline has ceased and that the population is stable or increasing since 2002. The whales are susceptible to human activities in their 4 breeding lagoons in Mexico, as well as to entanglement in fishing gear and collisions with boats throughout their range. Underwater noise associated with proposed oil development in BC could alter migration patterns. The small group of summer-resident whales could also be threatened by subsistence whaling in the USA.
Applicability of criteria
Criterion A: does not apply, although Criteria A4 (Threatened) is close to being met. However, the documented decline appears to be a fluctuation. Vital rates and other indicators suggest the population will not continue to decline.
Criterion B: does not apply. The extent of occurrence is > 20 000 km2.
Criterion C: does not apply.
Criterion D: does not apply. The number of mature individuals is 11 000.
Criterion E: no quantitative analysis has been undertaken.
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