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Some Whales Live Much Longer Than Previously Thought, a Discovery That Could Change How We Protect Them
Some Whales Live Much Longer Than Previously Thought, a Discovery That Could Change How We Protect ThemIn a new study, researchers use novel techniques to uncover more accurate life expectancy estimates of southern and North Atlantic right whales One in ten southern right whales lives past the age of 131, new research suggests. Paula Ribas / Getty ImagesRight whales are among the rarest whales on Earth, and their populations are highly endangered. Now, scientists say some of the gentle giants may live nearly twice as long as previously thought. The new findings, published December 20 in the journal Science Advances, makesouthern right whalesthe mammal with the second-longest known life span, behind only the bowhead whale. The findingsand the novel methods used to achieve themcould help inform conservation efforts moving forward.We were thinking about these whales all wrong, says study co-author Peter Corkeron, a marine ecologist at Griffith University in Australia, to the Guardians Petra Stock. Its impeded our ability to get it right when it comes to doing the science for conservation to stop these whales from going extinct.Estimating the age of some individual whales is relatively easy. For example, a bowhead whale (Balaena mysticetus) killed in 2007 had a harpoon tip stuck in its blubber that was manufactured in the late 1800s, allowing researchers to surmise it was at least 115 years old.But deducing the average life expectancy of an entire species can be more challenging. For one, past methodssuch as analyzing their earwax, which builds up each year like the rings of a treehave required whales to be dead. In addition, commercial whaling was so intense throughout the 19th and early 20th centuries that most of the largest, oldest animals were likely missing from researchers calculations. Most of todays longevity estimates are probably skewed by an overrepresentation of younger whales, the team writes in the paper.So, for the new study, researchers deployed some new tactics. Using photos of right whales dating back to the 1970s, they identified individual females based on their appearance and noted when they stopped showing up in photos, presumably because they died. Then, they incorporated this information into statistical models that are similar to those used by life insurance companies to estimate human life expectancy.These novel methods are quite impressive, as C. Scott Baker, an ecologist at Oregon State University who was not involved with the paper, tells Sciences Mitch Leslie. They make a good case for the plausibility of their results.The findings suggest southern right whales (Eubalaena australis) have a median lifespan of about 73 years. But up to 10 percent might live to be 131 years oldand a handful may even approach 150. Thats much higher than previous estimates, which suggested the marine mammals had a maximum life expectancy between 70 and 80 years.Researchers used the same techniques for North Atlantic right whales (Eubalaena glacialis), a critically endangered species with an estimated 372 individuals remaining. The study finds that North Atlantic right whales have a median lifespan of just 22 years, with the longest-living 10 percent surpassing the age of 47.Overall, the findings reinforce the idea that these animals are still bouncing back from the damage wrought by commercial whaling, a practice that ended less than four decades ago.To attain healthy populations that include old animals, recovery might take hundreds of years, says study lead author Greg Breed, an ecologist at the University of Alaska Fairbanks, in a statement. For animals that live to be 100 or 150 and only give birth to a surviving calf every 10 years or so, slow recovery is to be expected.Why such a big life expectancy gap between southern and North Atlantic right whales? Scientists suspect North Atlantic right whales are much more vulnerable because of where they live. They primarily inhabit Atlantic coastal waters near Canada and the United Statesa bustling region with lots of commercial activity.This month alone, three North Atlantic right whales were seen tangled in fishing gear off the East Coast of the U.S. Theyre also susceptible to boat strikes and climate change.Its a maze of rope these animals need to get through, and theres huge ports coming into the U.S., theres lots of shipping, Corkeron tells the Australian Broadcasting Corporations Sam Bradbrook and Samantha Goerling.The Southern Ocean, meanwhile, is not nearly as congested. One takeaway from the study is that its important to keep it that way, Corkeron adds.Moving forward, researchers say their methods could be applied to other species, such as blue, fin, sei, humpback, gray and sperm whales. And, in the meantime, their recent findings could lead to the development of more effective conservation plans.Understanding how long wild animals live has major implications for how to best protect them, Corkeron and Breed write in the Conversation. Animals that have very long lifespans usually reproduce extremely slowly and can go many years between births. Conservation and management strategies that do not plan accordingly will have a higher chance of failure. This is especially important given the expected impacts of climate disruption.Get the latest stories in your inbox every weekday.Filed Under: Aging, Animals, Atlantic Ocean, Conservation, Endangered Species, Health, Mammals, New Research, Oceans, Water, Whales, wildlife
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