Study Finds Great White Sharks Live Significantly Longer Than Previously Thought
Posted on January 10, 2014
A new study led by the Woods Hole Oceanographic Institution (WHOI) using bomb radiocarbon has found great white sharks live significantly longer than previously thought. The study also found great whites grow more slowly than previously thought. Age estimates were up to 73 years old for the largest male and 40 years old for the largest female. In previous studies, great white sharks were estimated to live to be only about 22 years old. The study was published here in PLoS One.
Li Ling Hamady, MIT/WHOI Joint Program student and lead author of the study, says in a release, "Our results dramatically extend the maximum age and longevity of white sharks compared to earlier studies. Understanding longevity of the species, growth rate, age at sexual maturity, and differences in growth between males and females are especially important for sustainable management and conservation efforts."
To determine the ages of sharks the researchers conducted radiocarbon analysis on collagen in the white shark vertebrae at National Ocean Sciences Accelerator Mass Spectrometry Facility at WHOI. Radiocarbon was produced by thermonuclear device testing done during the 1950s and 1960s. The researchers say this radiocarbon mixed from the atmosphere into the ocean, and was incorporated into the tissues of marine organisms living during that time period. The researchers were able to use this as a "time stamp" to help determine the age of an animal. Previous shark age studies assumed annual deposition of growth bands. The WHOI researchers say vertebrae bands in great white sharks don't necessarily signify annual growth.
Study co-author Greg Skomal, a WHOI adjunct scientist and MA Marine Fisheries biologist, says, "These findings change the way we model white shark populations and must be taken into consideration when formulating future conservation strategies."