How old is a lobster? Check his eyestalk

The age of a lobster, or a crab or shrimp, can be determined by counting growth rings, as is done with trees. But scientists aren't sure yet how old a lobster can live to be.

|
(AP Photo/Robert F. Bukaty
Scientists have now figured out that growth rings can be found in the eyestalk - a stalk with an eyeball on the end. Growth rings are also found in gastric mills - the teeth-like structures in their stomachs used to grind up food.

For the first time, scientists have figured out how to determine the age of a lobster — by counting its rings, like a tree.

Nobody knows how old lobsters can live to be; some people estimate they live to more than 100.

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, said Raouf Kilada, a research associate at the University of New Brunswick who was the lead author of a scientific paper documenting the process.

Before now, scientists deduced a lobster's age judging by size and other variables. But it's now known that lobsters and other crustaceans, such as crabs and shrimp, grow one ring per year in hidden-away internal spots, Kilada said.

RECOMMENDED: Are you scientifically literate? Take the quiz

"Having the age information for any commercial species will definitely improve the stock assessment and ensure sustainability," he said after presenting his findings Thursday at a scientific conference in Portland.

Scientists already could tell a fish's age by counting the growth rings found in a bony part of its inner ear, a shark's age from the rings in its vertebrae and a scallop or clam's age from the rings of its shell.

But crustaceans posed a problem because of the apparent absence of any permanent growth structures. It was thought that when lobsters and other crustaceans molt, they shed all calcified body parts that might record annual growth bands.

For their research, Kilada and five other Canadian researchers took a closer look at lobsters, snow crabs, northern shrimp and sculptured shrimp.

They found that growth rings, in fact, could be found in the eyestalk — a stalk connected to the body with an eyeball on the end — of lobsters, crabs and shrimp. In lobsters and crabs, the rings were also found in the so-called "gastric mills," parts of the stomach with three teeth-like structures used to grind up food.

To find the growth bands, the scientists dissected the eyestalks and the gastric mills, cut out sections and viewed them under microscopes.

Lobsters don't lose reproductive capabilities or organ functions or exhibit signs of aging as they get older, but nobody knows for sure how old they can live to be.

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

The paper was published in this month's Canadian Journal of Fisheries and Aquatic Sciences, a well-regarded peer-reviewed scientific journal based in Ottawa, Ontario, that has been published since 1901. Kilada's was one of more than 50 scientific presentations at the conference, attended by more than 100 lobster scientists from the U.S., Canada and Europe.

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

"Right now we're just guessing at their age," he said.

Kilada said he saw lobster specimens that were 16 or 17 years old during his research. He estimates that there are lobsters 60 or 70 years old living in the wild.

Susan Waddy, a lobster researcher with Canada's Department of Fisheries and Oceans, said she has kept lobsters in her laboratory that are more than 30 years old. She suspects they live to be 40 or 50.

"We know they don't live forever," she said.

RECOMMENDED: Are you scientifically literate? Take the quiz

Copyright 2012 The Associated Press.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to How old is a lobster? Check his eyestalk
Read this article in
https://www.csmonitor.com/Science/2012/1130/How-old-is-a-lobster-Check-his-eyestalk
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe