Aquatic Species at Risk - Killer Whale (Northwest Atlantic / Eastern Arctic population)
Species - Details
Dr. Lance Barrett-Lennard
SARA Status: Under Consideration
COSEWIC Status: Special Concern November 2008
Region: Nunavut, Manitoba, Quebec, New Brunswick, Prince Edward Island, Nova Scotia, Newfoundland and Labrador, Arctic Ocean
Did You Know?
With no natural predators, killer whales can live to between 50 and 80 years of age. That’s if they survive their infancy. Sadly, nearly half of all killer whales die between birth and the age of six months. This brings down this species’ average lifespan to 17 years for males and 29 years for females. Additionally, they calve only once every five years on average. All of these factors combined mean that killer whale populations tend to have extremely low growth rates. And that can make any threat to their survival a severe one.
Five designatable units (DU) have been identified for Killer Whales based on their genetic and demographic distinctions. Within the Northwestern Atlantic and Eastern Arctic designatable unit, this species has been identified as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is currently being considered for listing under the federal Species at Risk Act (SARA). Protection is currently afforded under the federal Fisheries Act. If listed under SARA, it will be afforded additional protection and a management plan will be developed.
The Killer Whale (Orcinus orca) is a member of the dolphin family, Delphinidae. It is easily recognized by its distinct black and white patterns. The Killer Whale is known as ‘aarluk’ in Inuktitut and has the following characteristics:
- Tall, uniquely-shaped dorsal fin on individual whales;
- Dorsal fin height of males is greater than that of females;
- Pectoral fins and tail flukes are longer in males than in females;
- Tail fluke tips curve downward in males;
- Unique grey-white area at the base of the dorsal fin, known as the ‘saddle patch’, helps to distinguish individuals;
- Longest male recorded at 9.0 m; longest female at 7.7 m;
- Heaviest male weighed 6,600 kg (7.65 m); heaviest female 4,700 kg (6.58 m); and
- Calves range from 2.2 to 2.5 m in length at birth.
Killer Whales are found in all of the world’s oceans. In the northern hemisphere, Killer Whales are found along the west coast of North America, near Iceland, and along the coast of northern Norway. In the southern hemisphere, they are often observed off the coasts of New Zealand, Tasmania, Argentina and southern Brazil. They are also abundant in the Antarctic. Killer Whales are present in all three oceans bordering Canada, as well as in Hudson Bay.
Their Canadian distribution includes the coastal waters of British Columbia from Haida Gwaii in the north to Vancouver Island. Little is known about the range and distribution of the northwestern Atlantic and eastern Arctic Killer Whales. Historically, they were common in the Gulf of St. Lawrence and St. Lawrence estuary; however, they are now most often recorded in the coastal waters of Newfoundland, particularly in the Strait of Belle Isle. Sightings in the eastern Arctic have increased over the past few decades, particularly within the Hudson Bay region, whereas Killer Whales are uncommon in the western Arctic.
Habitat and Life History
The specific habitat requirements and life history in the northwestern Atlantic and eastern Arctic Killer Whales are not well understood. They can tolerate wide ranges of salinity, temperature and turbidity. Females reach sexual maturity between the ages of 12 and 17, when they may give birth to a single calf. The time interval between pregnancies can vary between 2 and 11 years. Females prefer to mate with males who have different dialects than their own. Killer Whales are long-lived, with life expectancies between 30 and 46 years for females, and between 19 and 31 for males.
Killer Whales are predators. In the northwestern Atlantic and eastern Canadian Arctic, they have been observed feeding on marine mammals, fish and seabirds, as well as discarded fish from longline operations. Food preferences and foraging techniques, as well as knowledge of geographic and seasonal patterns of prey abundance, appear to be learned traits.
Little is known about threats to Killer Whales in the northwestern Atlantic and eastern Arctic. Degraded habitat quality due to physical and acoustical disturbances, and increasing levels of contaminants are likely threats to Killer Whale populations. Killer Whales on the east coast of Canada may also be vulnerable to toxic spills. In the Arctic, Killer Whales are also hunted.
There are no similar species.
Text Sources: Update COSEWIC Status Report 2008.
For more information, visit the SARA Registry website at www.SARAregistry.gc.ca and the Fisheries and Oceans Canada website below.
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