Study Reveals Technique to Measure Lobster's Age

First Posted: Dec 01, 2012 01:26 AM EST

Scientists from the University of New Brunswick say a lobster's age can be determined by counting its rings just like in trees.

Lobsters belong to an extremely diverse group of marine invertebrates. They have a reputation for being scavengers and even cannibals. They are capable of living up to over 100 years.

 Until now only guestimates were made about the age of lobsters based on size and other variables. Initially it was thought that when lobsters, shrimp and crabs molt, they shed all parts of their bodies that might record annual growth bands. But a team of international scientists have for the first time devised a technique to determine the age of lobsters.

"But knowing, rather than simply guessing their age and that of other shellfish could help scientists better understand the population and assist regulators of the lucrative industry," a research associate Raouf Kilada at the University of New Brunswick, lead author of a scientific paper documenting the process told the Huffington Post.

Marine biologists calculate a fish's age by counting the growth rings that are present in the bony part of the inner ear. They count the rings present on the shark's vertebrate to calculate its age and rings on the shells of clams determine their age. But when it came to lobsters and crabs, they found it challenging to calculate their ages as these lack the identifying parts mentioned above. The reason being they shed their calcified shells every year.

In order to decode this mystery, Kilada and five other Canadian researchers took a closer look at lobsters, snow crabs, northern shrimps and sculptured shrimps.

They noticed that two body parts of these animals don't molt off and this could provide evidence regarding the age of these crustaceans.

First is the 'eyestalk'- a stalk connected to the body with an eyeball at the end. Next is the 'gastric mills'-parts of the stomach with three teeth like structure that is used to crush the food.

The eyestalks and the gastric mills were dissected by the scientists to trace the growth bands accurately.  

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

"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 was quoted in Huffington Post.

Bayer agreed that this is the first time scientists have a direct method to place an accurate age on crustaceans.

The research was published in this month's Canadian Journal of Fisheries and Aquatic Sciences.

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