date:Mar 20, 2013
onic tagging devices to bluefin tuna to follow their movements through the sea. But it's difficult for scientists to wrestle with a live, torpedo-shaped fish that can weigh more than 1,000 pounds.
With that technology, researchers still don't know where the fish has been before it was
tagged or how many tuna are making the trip each year.
What the chemical techniques, like radiocesium, can do is tell you where an animal came from, said Madigan, who has gathered samples from more than 400 blue