L47 (Marina), a southern resident killer whale belonging to L-pod, is missing and likely dead after not being seen by researchers since February.
The 47-year-old orca was a grandmother and a matriarch, with three surviving descendants. Researchers say her death will have a profound impact not only on her family, but the entire social structure of her maternal line.
“Females, especially older females, are the glue that holds the pod together,” said Monika Wieland Shields, co-founder and director of the Washington-based Orca Behavior Institute, which studies killer whales in the Salish Sea. . “We see a lot of changes in the pod’s social associations when an older female is lost.”
The institute plans to closely monitor L47’s remaining family members to find out how they react to the loss of their leader, she said. “Some matrilines will stay together, even after a loss, but others will fracture in some way. We’ll be looking to see how his two daughters and son react in terms of who they associate with.
While the adult female offspring of L47 have their own calves and will adapt more easily to loss, the 11-year-old male L115 (Mystic) may not fare as well without his dam’s leadership.
“There is heightened concern about the survival of descendants she leaves behind… especially her young son,” said Wieland Shields.
“He’s a juvenile whale, so making sure he’s going to be able to survive the loss of his mother (is vital).”
According to the Washington-based Center for Whale Research, which first reported L47’s death, L115 is three times more likely to die in the next two years than a man of the same age with a surviving mother.
Its reduced chances of survival – and those of other Southern Resident Killer Whales – are all the more worrisome given the declining conditions of killer whales in the Salish Sea.
“In an age where salmon are so few and noise and pollution are a stressor, threats to killer whales are only growing,” said Christianne Wilhelmson, Executive Director of Georgia Strait Alliance, an advocacy group committed to protecting the local marine environment. .
Killer whales can be identified by using markings on their dorsal fins and back. They are classified into types based on their appearance, diet, social structure, and coastal range.
Bigg’s Killer Whales and Southern Resident Killer Whales are found in the Salish Sea and differ not only in appearance, but also in their chances of survival.
Bigg’s killer whales hunt seals, sea lions and porpoises and have continued to thrive off the coast of British Columbia, while southern resident killer whales rely primarily on chinook salmon for food. Their ability to hunt has been severely restricted by the decline in the fish population.
Wilhelmson said restoring salmon numbers, along with reducing noise pollution and vessel traffic, are the best ways to ensure at-risk killer whales the best chance of survival.
“There have been measures put in place (to protect killer whales) over the past two years that have been positive, but they haven’t been enough,” she said. “The government does not want to go as far as necessary. “
With the loss of L47 and the confirmed summer death of member K-pod K21, the Center for Whale Research said there are now 73 Southern Resident Killer Whales swimming in the Pacific.
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