Scientists have found a new way to determine the age of lobsters - by counting their rings, just like trees.

Lobsters are crustaceans that belong to a large group of arthropods that include shrimps, crabs and krill. Until now, it was estimated that lobsters live for more than 100 years.

Researchers have assumed the age of lobsters based on their size and other variables. But they have not been able to find the age of the lobsters as they lacked any permanent growth structures. It was previously thought that lobsters shed all the calcified body parts, which record the annual growth bands, reported Associated Press.

Moreover, these crustaceans do not show any signs of aging, which has made it hard for scientists to detect their age.

For the first time, a team of researchers led by Raouf Kilada, a research associate at the University of New Brunswick, has found a new method to determine lobsters' age.

The research team closely examined snow crabs, lobsters and shrimps. They proposed that the growth bands could be found in the eyestalk (mobile stalk-like structures that bears an eyeball at the tip) and gastric mills (arrangement of teeth and small bones in the stomach to grind food particles) of these crustaceans.

Experts dissected the eyestalk and gastric mills and observed them under a microscope to find the growth rings. Based on their study, the research team also found that the lobsters grow one ring every year.

"We've thought lobsters could live to 100 years old, and this new aging technique will be a way to document that," Bob Bayer, executive director of the University of Maine's Lobster Institute, told the Associated Press.

"Having the age information for any commercial species will definitely improve the stock assessment and ensure sustainability," said Kilada.

The findings of the study are published in the Canadian Journal of Fisheries and Aquatic Sciences.