Study: Bluefin Tuna Cross Atlantic Ocean
By examining the chemical composition of the otolith, or ear stone, of bluefin tunas, researchers found that tunas from North America and the Mediterranean intermix as juveniles, a discovery that could affect how tuna fisheries are managed.
While bluefins from both sides of the Atlantic return home to spawn, researchers found that the largest tuna, sought by commercial fishermen off North America, tend to be local fish, and smaller ones caught by sport fishermen often have Mediterranean origins.
The study, led by Jay Rooker of Texas A&M University and David Secor of the University of Maryland Center for Environmental Science, is published in this week's edition of the journal Science.
"Juveniles are not conforming to the principal premise of how they've been managed - that fish keep to their own side of the Atlantic," says Secor. "This could be particularly troubling if North American juveniles head to the Mediterranean. High exploitation there might mean that few make it back. Evaluating where Mediterranean juveniles originate should be our next highest priority."
The International Commission for the Conservation of Atlantic Tunas meets next month in Morocco to discuss declining tuna stocks and ways to better manage the species.