LThat same month, a sick orca living in the southern Pacific Ocean gave researchers a rare moment of hope. A new baby whale has been spotted swimming with its mother. To that point, only one calf had appeared this year, which died a few months later.
But by mid-October, the new calf, named L128, appeared to be in poor health, and researchers at the Whale Research Center observed the older orca swimming with the calf over its nose. He looked “stubby and thin.”
Another whale “was shaking its calf, as if desperately trying to revive it.” Field biologist Mark Malleson believes he saw the calf “take a faint breath” and resume swimming. the center saidHowever, it is unknown whether she is still alive.
The tragedy of the endangered southern killer whale, long seen as a reflection of an ecosystem in crisis, has sparked intense debate among fishermen, whale-watching companies and the shipping industry. There is a lot of criticism.
Underlying this responsibility is the idea that whales cannot consume Chinook salmon, a species that is their main food source and has suffered a catastrophic collapse.
But a new study from the University of British Columbia overturns that assumption, revealing that whales can consume far more Chinook salmon than their much healthier relatives, the northern killer whales. This new discovery deepens the mystery of what is driving whales to the brink of extinction.
“That really surprised us. And we look at the data very diligently because we're sure we've made a mistake somewhere. We checked everything three times, and then after peer review, the numbers are still the same. ,” said Andrew Treitz, co-author of the report and head of the university's Marine Mammal Research Unit.
Research published in journals Pro Swan, They investigated the food available to southern residents of 73 whale ecotypes spanning a geographic range from southern British Columbia to California. Split into three pods, the whales spend the summer off the coast of Vancouver Island. The researchers also investigated food availability for northern killer whales. There are 34 killer whales in the population from Alaska to southern British Columbia, and their population is increasing along with the southern whales around Vancouver Island.
“If you ask anyone ahead of time what they're going to find, it's clear: There's not enough fish for people in the south,” Trites said. However, after meeting with sport anglers and whale watching crews, the team discovered that Chinook available to whales in the south were relatively abundant.
“In the Salish Sea, with all the protections and restrictions in place, access to food doesn't really seem to be an issue. You need to think about feeding every day of the year, not just when you're there,” Trites said. “What should I do about my winter and spring diet?'' This may become a bottleneck. So we spend so much time focusing on our backyards that we may not be thinking about what happens when they're not in our backyards. ”
Although prey is more readily available to whales, Trites cautions that this does not mean they have access to fish.
The study found that the noise of maritime traffic can “mask” communication between killer whales and impede their hunting ability. The presence of large ships can also interfere with their foraging activities.
“Orcas are more likely to encounter ships in the Salish Sea than in the north.” [Vancouver] “Despite the abundance of Chinook in island waters, this may mean southern residents have less access to salmon than northern residents,” the study said.
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Environmental groups have long been concerned about the impact of increased shipping traffic along British Columbia's southwest coast, as construction of the Trans Mountain oil pipeline ramps up and construction of a liquefied natural gas (LNG) terminal progresses. Ship traffic is expected to increase rapidly in the coming years. Opened.
“There is no question that southern resident killer whales will encounter more ships and shipping traffic. Will they be able to adapt to that, or will they have yet another straw on their backs and add stress to their recovery? Does it just make it more difficult?'' Trites said.
As Trites points out, the southern killer whale population has remained relatively stable for more than half a century, though it is thought to have numbered more than 200 individuals in the early 20th century.
Much of the decline can also be traced back to its dark history in the early 1900s, when whales known as “blackfish” were slaughtered by fishermen and then harvested in large numbers for use in aquariums. It was only when Canada banned the capture of orcas in the 1970s that the orca population found a respite.
“If you look at the marine mammals in the Salish Sea, it's only the southerners who have a problem,” Trites said. The Salish's nutrient-rich waters were once a renowned whale habitat until rampant whaling pushed humpback and fin whale species to local extinction. However, with the end of the large-scale killing, the population has recovered. The area is currently home to record numbers of harp seals, as well as healthy populations of California sea lions and porpoises.
“So the only outliers are the southern killer whales,” Trites said. “Is it a Salish Sea problem?” Or are they bringing the problem with them? ”
