From left, Carl Huntsberger, graduate student, UMaine School of Marine Sciences; Dr. Raouf Kilada, University of New Brunswick; and Dr. Rick Wahle 
of UMaine
From left, Carl Huntsberger, graduate student, UMaine School of Marine Sciences; Dr. Raouf Kilada, University of New Brunswick; and Dr. Rick Wahle of UMaine
University of Maine research professor Dr. Rick Wahle and UM?graduate student Carl Huntsberger are testing a new technique for determining the age of lobsters at UMaine’s Darling Marine Center in Walpole, in a project jointly funded by Maine Department of Marine Resources and Maine Sea Grant. 

Lobsters molt as they grow, discarding their outer layer and with it any external record of growth. The traditional way of estimating a lobster’s age by its size is inaccurate, because the creature’s growth rate is affected by ocean conditions. This poses problems for scientists and fishery managers trying to measure the animals’ health and the sustainability of the stock. 

Dr. Raouf Kilada, of University of New Brunswick, has found that lobsters (and crabs) have internal structures that exhibit patterns similar to tree rings — bands, less than a millimeter thick, in the wall of the gastric mill, a part of the stomach that grinds up food. Kalida is working with laboratories like DMC to validate that those bands do indeed show annual growth, and he visited Walpole this winter to share with Wahle and Huntsberger the analysis technique he developed. Lobsters have their gastric mill stained with fluorescent dye. After being held in captivity for three years, they are dissected, samples of the gastric mill wall are embedded in epoxy, and the researchers use a microscope to count the bands. Preliminary research results indicate that the bands do represent annual growth patterns.