The federal Department of Fisheries and Oceans plan to learn more about the giant bluefin tuna that are being landed off the coast of Prince Edward Island.

They're examining a small bone found in the inner ear of the fish called an otolith.

Inside a warehouse on the Tignish, P.E.I. wharf are large drums filled with about 20 tuna heads

Dheeraj Busawon is a DFO technician who is cutting the heads in two and then extracting a very tiny bone from the ears of each fish. From those bones they can tell the age of the tuna and the waters where they came from.

"Basically it's like reading rings on a tree," said Besawon. "There are rings in a section and once you place it on a microscope, that's how you determine the age."

Doug Fraser is one of the co-chairs of the Bluefin Tuna Advisory Committee. He says the information will go to the International Commission on the Conservation of Atlantic Tuna. The group is concerned about overfishing.

"We're hoping that they're born in the Gulf of Mexico to prove they're western-oriented fish which will hopefully help Canada and the United States have a better argument on future quotas," said Fraser.

Buyers from Japan and the U.S. pay thousands of dollars per fish — a key ingredient in sushi. But local fishermen like Kenny MacRae say the tuna being landed this year are smaller and the price in Japan is soft.

"It seemed like it maxed out at a top price of $5,000 or $6,000, that seems to be the top," said Macrae. "Last year you got as high as $10,000."

Fishermen are allowed to catch at least one tuna, and possibly more later, depending on how many are caught early.

And depending on the quality of the fish, it could mean a big pay day.

The fishermen and scientists are hoping that the tests will give experts a better understanding of tuna stocks.