By Caitlin Birdsall
A male killer whale alone near Gwaii Hanas. This was the report the BC Cetacean Sightings Network received twice in early August. If this had been a resident (fish-eating) killer whale, there would have been cause for concern; resident killer whales always travel with their matrilineal families. However, this sighting came with a crucial piece of the puzzle: photos! Upon further inspection of the dorsal fin and saddle patch (the ‘fingerprint’ of a killer whale), the Wild Whales team was able to identify this lone ranger as T12A (known as”Nitinat” to the Wild Killer Whale Adoption Program), a male transient (mammal-eating) killer whale.
Transient killer whales are genetically and acoustically different from resident killer whales. They have a much looser social organization- a sighting of a lone transient is not unheard of. They are stealthy hunters, feeding primarily on other marine mammals; seals, sea lions, dolphins, porpoises and even other whales! Compared to resident killer whales, transients tend to be elusive, unpredictable, and far ranging.
So who is this lone whale? And why is he alone? T12A was born in 1982, to T12 (“Pachena”). The T12 group is one of the better known south coast transient groups, first spotted off Race Rocks near Victoria by Dr. John Ford in 1980 and frequently seen around Vancouver Island and the Queen Charlotte Islands since then. T12A has been spotted solo for the past few years; his mother has not been seen since 2005. While female transients will often disperse from their mothers around the time of their own first calf, according to Dr. Ford of Fisheries and Oceans Canada, roving, solitary males are usually alone because their mothers are gone. This, however, doesn’t mean he’ll spend the rest of his life solo; T12A will most likely spend approximately half his time associating with other transient killer whales.
In fact, it is one of these associations that had T12A in the news 6 years ago. Transient killer whale groups will often join together to pursue larger prey. On October 15, 2002 T12A and his mother joined T11 and T11A to pursue a minke whale in the Ganges Harbour of Salt Spring Island. The entire predation event took over 7 hours of work for these whales, who contended with the tide and even had to pull the 9-m minke out of shallow water!! This event demonstrated the amazing coordination and effort used by hunting transients. During the pursuit the whales flanked the minke from all sides, preventing its escape, rammed its sides repeatedly, weakening the minke, and even swam up on top of it, forcing its head underwater. A photo of this event can be seen on the Wild Whales killer whale page.
While predation events like these showcase transients as formidable predators, it does not protect them from a greater threat in our ocean, persistent organic pollutants (POPs) such as PCBs and PBDEs. Work done by Dr. Peter Ross of Fisheries and Oceans Canada has shown that male transient killer whales, like T12A, are some of the most polluted marine mammals on earth. Their place at the top of the marine food chain amounts to a huge amount of persistent toxin accumulation which may affect development, reproduction and immune system function in these whales. T12A would hold higher levels than his female counterparts due to the nature of these toxins. They store in fat, and while both male and female whales have big blubber layers that store these toxins, females download some of their toxins to their calves while pregnant and lactating. Some of these toxins are now banned in North America and Europe, others like fire-retardants containing PBDEs are still being used. Learn more about these toxins and what you can do to reduce them here.
A recovery plan for transient killer whales like T12A has recently been finished by Fisheries and Oceans Canada. You can continue to follow T12A’s story and support wild killer whale research and conservation by adopting him through the Wild Killer Whale Adoption program. You can also help us learn about all marine mammals by reporting any whale, dolphin, porpoise and sea turtle sightings to Wild Whales.
For more information:
Killer whale natural history
Transient killer whales of British Columbia and South-east Alaska Photo Identification Catalogue