TAMPA (CBS Tampa) – New research shows great white sharks can live past 70 years, which is a surprise to marine biologists.
“White sharks in the northwest Atlantic are considerably older than previous age estimates,” Li Ling Hamady, an oceanography graduate student at Woods Hole Oceanographic Institute in Massachusetts and co-author of this study told LiveScience.
Previously, scientists would look at a shark’s teeth, ear bones, or vertebrae and count each stripe to correspond to its age, like counting rings in a tree.
Hamaday and her team looked at the carbon-14 that fell into the ocean after nuclear bomb testing between the 1950s and 1960s. They were able to analyze the radiocarbon from the vertebrae of four female and four male great white sharks that were captured from the Atlantic Ocean between 1967 and 2010.”The nuclear testing provides a time stamp for us to determine when these tissue layers were deposited,” Hamaday added to LiveScience.
The authors were able to count the rings before and after. They found that the “tree rings” were laid down in annual stripes for small to medium-size sharks but there was a change in how often the bands appeared.
Researchers were able to determine that the oldest male shark was 73, and the oldest female shark was 40.
Hamaday and her associates suggest that sharks may have a similar life cycle to humans. The study showed that sharks mature slowly and take longer to reproduce.
“The longer lives of great white sharks are consistent with increased life spans being found using the same method in sandbar and tiger sharks,” Allen Andrews, a biologist at the National Oceanic and Atmospheric Administration Fisheries – Pacific Island Fisheries Science Center in Honolulu, but was not involved in this study told LiveScience. “There’s basically missing time in the vertebrae of these sharks. We’re finding the vertebrae just stop growing, and very likely if there is growth there, it’s too small to see, or maybe it’s lost in the cleaning process.”
The study was published in the journal PLOS ONE.