Great White Sharks Live Way Longer Than We Thought: Jaws Could Have Been In His Seventies
A new study published Wednesday in PLOS ONE shows that great white sharks can live past 70 years — much older than other studies have suggested.
For years, biologists have been counting the number of marks on individual shark vertebrae to come up with its age. Add them up like tree rings, and a scientist would know how long the big fish had lived — or so they thought.That method was largely ineffective, according to the National Oceanic and Atmospheric Administration, which led the study. Sometimes the marks were tiny. Sometimes as the sharks get older, new marks don't show up every year like they used to. "Age is therefore frequently underestimated," said Lisa Natanson, a NOAA fisheries biologist who co-authored the paper, in a statement.
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The best way to measure their age, it turns out, has to do with Cold War nuclear weapons testing. Scientists call it "bomb radiocarbon dating" because it literally relies on the extra Carbon-14 that nuclear bomb detonations released into the atmosphere. That carbon settled into the oceans and was absorbed by sea creatures in the 1950s and '60s. The result is basically a time stamp that pretty accurately reveals the birthday of any fish old enough to remember the Cold War.
That's the method Natanson and her colleagues used to find the ages of eight great white sharks caught in the Northwest Atlantic Ocean between 1967 and 2010. The oldest male was 73 years old, 34 years older than the one made legendary in the Steven Spielberg film. Other studies of Pacific Ocean great whites using the vertebrae-counting method found massive sharks to be in their teens and early twenties. The oldest was 23. "Either white sharks are living significantly longer and growing slower in the [Northwest Atlantic] than either the Pacific or Indian Oceans, or longevity has been underestimated in previous studies," the authors concluded.
This new knowledge changes things about the great white. Already overfished in some parts of the world for soup and necklaces, they're considered a vulnerable species by the World Wildlife Fund. Their long lifespan makes them one of the oldest-living fish, which NOAA says actually makes the great white even more vulnerable. "Sharks that mature late, have long life spans and produce small litters have the lowest population growth rates and the longest generation times," they said. So not only are great white sharks older than previously thought, they're "more sensitive to fishing pressure than previously thought."
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