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The Answer is Black and White
When driving the sea to sky highway, it can be tough to focus on the road between catching glimpses of the glimmering waters of Howe Sound.
Rightly so, because Howe Sound is a beautiful example of BCʼs coastline. Sadly, past and present human development including pollution, highway construction and even historical whaling have all compromised the health of this local marine environment. The good news is that Howe Sound is a shining example of what can be done to revitalize an entire ecosystem when communities and government cooperate. A water treatment facility has cleaned up heavy metal pollution from the Brittania copper mine, and wrapping creosote-covered pilings with non-toxic landscape fabric has provided a healthy platform for herring eggs to survive. Pink salmon have even returned to spawn. Perhaps one of the most obvious results of revitalization efforts is the presence of marine mammals in Howe Sound, especially cetacean species such as killer whales and Pacific white-sided dolphins.
Any long-time Howe Sound local can attest to the fact that whales, dolphins, and porpoises were not a very common occurrence in the last few decades- but things have changed! Pacific whitesided dolphins have been frequent visitors to the Sound in the last two years, but there is another, substantially larger, dolphin species that also seems to have re-discovered the bounty of the area. In the past few years, sightings of killer whales in Howe Sound have increased. In fact to-date in 2011, the BC Cetacean Sightings Network (BCCSN) has received 17 sightings of killer whales in Howe Sound. In 2010 it was 14 sightings, and in 2009 it was 9 sightings. What many people may not know however, is that killer whales in BC are found in three distinct populations, residents, transients, and offshores— and that the killer whales spotted in Howe Sound are most likely southern residents or transients.
Resident killer whales on the BC coast are divided into two groups referred to as the northern resident and southern resident communities. These two communities are in fact distinct populations and genetics have shown us they have not mated together for roughly 15,000 to 20,000 years. There is some geographical overlap between the ranges of northern and southern residents, however, the two communities are seldom observed in the same area at the same time and have not been seen to interact with one another. Killer whales are highly social and vocal animals, and residents in particular are a prime example. They are often surface-active, and can be seen breaching and tail-slapping. They also live in a complex matriarchal society, in which both males and females remain with their mother indefinitely, even after they have offspring of their own. Family units stemming from a living or recentlydeceased matriarch are called matrilines. Resident killer whales are salmon specialists, in fact research conducted by John Ford an Graeme Ellis of Fisheries and Oceans Canada has shown that ninety six percent of their summer diet is made up of salmonid species, primarily Chinook.
They often find their pretty using echolocation, which works just the way the name suggests—the whales produce loud clicking sounds and listen for the echoes. The whales use this echolocation frequently to build a picture of their surroundings to locate food or navigate underwater.
Transients (also known as Biggʼs killer whales) prey on marine mammals and can be found from Alaska to the southern California coast. They often hug the coastline, where seals and harbor porpoises are most common.
Harbour seal numbers in BC have increased since the 1970ʼs, and it is likely that transient killer whales are
benefitting from their rising numbers.
They are stealthy hunters and do not echolocate and vocalize nearly as often as their resident counterparts. This is because their marine mammal prey has excellent underwater hearing, and can easily detect a transient whale if it is noisy. Instead of making sounds to locate food, transients hunt in nearsilence by listening for prey. Probably for the same reason that transients are quiet acoustically, they rarely engage in conspicuous surface activity, unless of course, when attacking their prey.
Transients also usually travel in smaller groups than resident whales. Like residents, transients are matrilineal, but there can be dispersal from the family groups. Female transients will sometimes leave their mothers when they have had calves of their own.
As their name suggests, offshore killer whales inhabit areas well away from the coast. Not as much is known about offshore whales as encounters are few and far between. They are thought to be more closely related to resident killer whales than transients due to appearance, vocalization and genetics.
There is evidence to support that offshore whales feed on large ocean fishes such as sharks and halibut. Offshore killer whales are very vocal and use echolocation frequently, much like resident killer whales. They are typically encountered in groups of 30 – 70, but their social structure remains a mystery.
BCʼs four killer whale populations are all listed under Canadaʼs Species At Risk Act. Southern residents are listed as endangered, while northern residents, transients, and offshores are all listed as threatened. So what can the public do to help protect killer whales? Follow the Be Whale Wise Guidelines (online at lionsbay.net) while boating to minimize the risk of disturbance and injury to whales and dolphins, choose sustainable seafood to ensure a healthy ocean ecosystem, and participate in research by reporting your sightings to the BC Cetacean Sightings Network.
If you spot a killer whale, or any other whale, dolphin, or porpoise in BC waters, we want to know! Your reports will help us learn more about the occurrence, distribution and relative abundance of these animals. Visit www.wildwhales.org and fill out an online sightings form, or give us a call at 1-866-I-SAW-ONE. To learn more about killer whales, check out www.killerwhale.org.
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