- The long disappearance of southern resident killer whales from their usual summer habitat raised alarm bells for researchers along the coast.
- Explanations like the decline in salmon populations don’t fully match up with the dramatic change in behaviour observed in the southern resident pods.
- Scientist Andrew Trites says the loss of the longest-known matriarch in the southern resident killer whale population is a somewhat overlooked crisis in the J pod structure.
This summer saw the disappearance of southern resident killer whales from the Salish Sea for over 100 days. Researchers, whale watchers, policymakers—all who had become dependent on the reliable schedule of the endangered mammals—were left in limbo as they waited for their return.
With heatwave after heatwave bringing the province to its knees, causing mass death of marine life along the coast, one could be led to believe it was the climate crisis that had chased the J pod from the region.
But for Andrew Trites, director of the University of British Columbia’s Marine Mammal Research Unit, a far greater change in the environment is influencing the behavior of the three pods, a change that J pod especially has been grappling with for the last three years.
“We’ve got decades and decades and decades of research that’s been done, and they just showed up like clockwork. And, all of a sudden, they’re not here anymore, or they’re coming in later and later and less predictably. And so a number of people went to, ‘Well, it’s because there’s a shortage of salmon.’”
Much has been said about the decline in salmon off the coast of B.C. But Trites believes that in this case, the salmon are only part of the story.
“A couple of things don’t quite sit right with that explanation. The first is to say, what changed in 2017? The decline of salmon has been a kind of a drawn-out decline. There wasn’t a major shift in salmon abundance for the last four years.”
What did change, Trites explains, was that the matriarch J2, nicknamed Granny, died in December 2016 at the age of roughly 106 years.
“She was the oldest known killer whale to ever live. And we know that in killer whale societies that the pods and therefore the decision-making is being led by the eldest female,” says Trites.
Death of southern resident killer whales’ matriarch appears more ‘catastrophic’ than environmental changes
Numerous environmental factors are affecting the local killer whale populations, such as noise disturbance from boats, ocean pollution and declining numbers of salmon, evidence does show. But the shifting hierarchy within J Pod, and the changing dynamics between all of the pods, was more sudden than these environmental factors, says Trites.
“If changes were paralleling the slow decline of salmon…we would have seen this change of behaviour slowly over time. But this change was like someone turned off the light switch. It was just such a dramatic change. What happened catastrophically in their environment? Well, the catastrophe, I think, was the death of the matriarch.”
Researchers have been following these killer whales since the 1970s, but that’s been entirely under the reign of J2, Trites says. Scientists have yet to understand how the granddaughters and great-granddaughters will strategize to survive in rapidly changing waters.
Though he says much research focuses on the matriarchal structure of pods and their complex culture and language, the question remains: What happens to resident killer whale pods when the eldest female dies?
For decades, the seasonal presence of J Pod in the Salish Sea between April and September had become so reliable that scientists and the tourism sector had structured observation seasons around it. But this was all according to the schedule of one matriarch, Trites says. And because J, K and L pods have overlapping maternal lines, Trites says changes are likely among all of these southern resident groups.
Since the death of Granny, scientists have seen the southern resident orcas come back to the Salish Sea from California coastal waters much later, in September and October.
“We set our clocks and field seasons based on knowing when they’re going to be here. But we’re watching history as well,” says Trites.
A ‘dramatic change’ in social order and culture
The jump to blaming humans solely for the change in J Pod’s behaviour overlooks a vital fact about killer whales, a species that are documented to have their own cultures, languages, practices and reactions to trauma like the death of a family member.
“Currently we only have research on the behaviour of the whales under the reign of a single matriarch, in the same way that you might have known only Queen Elizabeth. When she dies, I don’t know what the new monarchy would look like. Our lifetime understanding of how the British monarchy works in the Commonwealth is based on the reign of one monarch.”
The rush to find a clear-cut answer for the summer shift in behaviour overlooks the complexities of killer whales, says Trites.
“Either you recognize that killer whales have a culture, that they’re led by the eldest female, that some stay with their mothers their entire lives. Or you go the other way, ‘No, they’re only food-driven, they’re just basic animals, everyone’s in it for themselves.’ That just doesn’t fit. I think we have to interpret what we see in light of all the research and behavior and the culture that we’ve come to know.”
A clearer understanding of the culture of the pod under its emerging leadership may also inform how they can be best protected. The government has been experimenting with fishing closures and no-go zones for vessels in certain regions of the Salish Sea, based on what researchers knew about their previous movement patterns.
“We think we understand these animals, and then they throw us a curveball and we realize we don’t truly understand them. With each year that goes by, we learn more and more… and realize just the flexibility and different ways in which killer whales cope with the changes that they face.” [end]