Feeding and Migration Patterns of Whales
Orca (Killer) Whales
In British Columbia, there are three distinctly and genetically-different populations of orca (killer) whales with highly-specialized feeding habits. They are residents, transients and offshore. Resident orcas feed primarily on salmon and travel in pods of six to 50 whales. Transient orcas feed on marine mammals including seals, whales and sea birds and travel in small groups of one to five whales. Offshore orcas live in the open ocean, travel in pods and eat only fish.
Resident orcas follow the salmon migration routes in the summer and disperse in the winter, but can typically still be seen all year long. A resident pod may travel up to 800 kilometres, where the transients’ range extends beyond the BC coast, up to 1450 kilometres along the coast from Alaska to California. Transients are found on the coast year-round, but are not common or predictable at any time. No reliable world population estimate exists for orca whales.
Gray Whales
Gray whales participate in the longest migration of any animal. A year for the gray whale begins in late December when hundreds of pregnant females, along with the rest of the herd, arrive in the warm calving lagoons of Baja, Mexico, after completing an arduous 8,000 kilometre swim, nonstop from the Arctic. Within days of arriving, each cow gives birth to a single calf.
In mid-February, the whales begin their migration north to their summer feeding grounds in the Bering Sea and Arctic Ocean. Approximately 20,000 gray whales migrate along the west coast of Vancouver Island. They stop to rest and feed in the Island’s protected bays, ending a fast that began the previous fall. These whales, with the exception of 40 to 50 resident whales who spend the entire summer feeding off Vancouver Island, reach the Artic by June.
The best locations to observe the resident and migrating gray whales are the Vancouver Island communities of Tofino, Ucluelet and Long Beach in Pacific Rim National Park. The giant, 30-ton whales can be seen from shore as early as February, with the females and calves passing in April and early May. Starting in September, the whales begin their return migration, by the same route, to their wintering areas in Baja.
The gray whale belongs to a family known as baleen whales and is the only bottom-feeding whale. It scoops mud from the ocean floor and feeds by straining huge mouthfuls of mud and seawater through filter-like baleen plates in its mouth. Tiny marine organisms are captured by the baleen and then swallowed by the whale. These large, slow whales are often encrusted with barnacles and other marine life that are visible when they surface.
Humpback Whales
There is a global population of approximately 10,000 humpback whales. Once considered a common species, the humpback whale is now currently listed as threatened and its numbers are recovering. About 2000 humpback whales inhabit the North Pacific. They breed in the waters off Mexico and Hawaii and then migrate to the North Pacific to feed in the summer.
The humpback whale is a medium-sized baleen whale. Like other baleen whales, humpbacks feed by filtering seawater through their baleen plates. To feed, several humpback whales will often create a ring of bubbles, called a "bubble-net", to concentrate small fish and crustaceans in one area where they can be more easily consumed. This technique is unique to this species of whale.
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