Approximately 7,000 Humpback Whales Starved To Death Due To A Severe Marine Heat Wave Known As “The Blob,” Prompting Even More Concern About Climate Change
Between 2012 and 2021, the number of humpback whales in the North Pacific Ocean experienced a decline of 20 percent, likely from a massive marine heat wave that began in 2013 and lasted until 2016.
Over the last two decades, a team of researchers has been tracking the population trends of the species.
In 1986, the International Whaling Commission implemented a moratorium on commercial whaling, helping humpback whales bounce back from the brink of extinction. The whaling ban remains in place today.
The researchers believed that the number of humpback whales would have grown even more since then, but to their surprise, they found that the whale population had actually dropped.
From 2002 to 2012, humpback whales in the North Pacific Ocean went from 16,875 to 33,488. But then, between 2012 and 2021, only 26,662 humpbacks were left alive.
These findings suggest that the marine heat wave of 2013 to 2016, sometimes known as “the blob,” is to blame for the sharp decline. It was the largest one ever recorded in the world.
During this period, the ocean temperatures were four to 10 degrees Fahrenheit higher than usual, causing around 7,000 whales to starve to death.
The event contributed to the loss of resources. More marine animals were competing for food that was less available. Zooplankton became less nutritious, which meant that fish were smaller. Humpback whales depend on those fish for food, but they aren’t getting enough calories from them because of the marine heat wave.
The whales became thinner, more susceptible to contracting disease, and less likely to reproduce. Fewer whales and calves were spotted at breeding grounds during that time.
gudkovandrey – stock.adobe.com – illustrative purposes only, not the actual whale
Other factors, such as collisions with ships and entanglements in nets, may have also played a part in the humpback whales’ demise, but they can’t explain such a significant population decline in a short period of time. Therefore, the marine heat wave has to be the main cause.
The intensity of the heat wave is almost certainly the result of global warming. Researchers fear that marine heat waves will grow more frequent, leading to additional problems in the future.
While the loss of humpback whales is a major concern, mass die-offs of several other animals have occurred as well.
For instance, a million Pacific seabirds and around 10 billion snow crabs died due to the heat wave, which affected crab fishing, a source of income that local communities rely on. In addition, “the blob” has led to changes in sea turtle and salmon migration routes.
“This is unlikely to be a one-time event, and if we do not rapidly curb the causes of climate change globally, more marine heatwaves decreasing ocean productivity worldwide will be our future,” said Ted Cheeseman, the lead author of the study and a conservation biologist at the Southern Cross University in Australia.
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