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How far do Southern Resident Orca pods travel?
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Orca whale families — often referred to as “pods”— may travel an average of 75 miles a day, and are capable of sustaining an average speed of over 6 knots (nearly 8 miles per hour) for long periods of time. These whales are also capable of traveling over 30 miles per hour for short periods.
Whether they are a small “transient” pod or a large group of “resident” whales, orcas are in constant motion, socializing, foraging, feeding, resting, playing or just traveling. The whales navigate the ocean depths day in, day out in a generally constant search for food — salmon, seals, or even large whales.
When photo-identification studies first began in British Columbia during the early 1970s, it was quickly found that there were two separate and distinct populations in Pacific Northwest coastal waters.
These two communities were designated the “Southern community” and the “Northern community,” in direct relation to their travel patterns in and around the waters of Vancouver Island.
The Southern community whales were most often encountered off the southern end of Vancouver Island — including the inland marine waters of Washington state — whereas the Northern community whales were most often encountered off the northern Vancouver Island region, including Queen Charlotte Sound and southern Southeast Alaska.
As a result of more than thirty years of study, it is now well known that the annual summer feeding grounds for Southern community orca whales encompass the inland marine waters of Washington state, particularly around the San Juan Islands and lower British Columbia. |
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This focused distribution is due to large numbers of Pacific Northwest salmon returning to the Fraser River in British Columbia.
During the autumn months in recent years the whales shift their travel patterns southward, following salmon heading to rivers draining into Greater Puget Sound.
During the winter months, however, the whales spend a increasing amounts of their time in the outer coastal waters; and, in recent years some members of the Southern community — K- and L-pods — have been observed as far south as Monterey, Calif., and as far north as Langara, Queen Charlotte Island.
On several occasions all three Southern community pods have been observed returning to the inland waters of Vancouver Island from the north in late spring — through Johnstone Strait — on their way to the San Juan Islands. They circumnavigate Vancouver Island.
Over the past three decades of study employing photo-identification methods developed here, an astonishing amount of bio-geographical information has been learned about orca populations world-wide.
For example, there are separate and distinct salmon-eating populations frequenting the Soviet Kamchatka Peninsula, the Aleutian islands, Prince William Sound and Southeast Alaska, northern British Columbia, and southern British Columbia (our whales).
There is a more oceanic population of fish-eaters that have been found to be related to the ancestors of all of these populations.
And finally, there is a meat-eating population, called “Transient” that travels widely in smaller groups feeding upon seals, sea lions, other whales, dolphins, and porpoises. Some transients have even been observed in the San Juan islands only to be seen in northern Southeast Alaska just a few weeks later.
— with Ken Balcomb, director of the Center for Whale Research.
Illustration courtesy Kelley Balcomb-Bartok/All Rights Reserved
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