Those countries fish nearly all the bluefin caught in the region. While their numbers have risen quickly, Pacific bluefin tuna are still ... have recorded them swimming from California to Japan ...

The Atlantic bluefin tuna is one of the largest ... among the most ambitiously migratory of all fish, and some tagged specimens have been tracked swimming from North American to European waters ...

Bluefin tuna are an ocean-going fish that grow up to 10 feet long and can weigh as much as 1,200 pounds. Unlike almost all fish, bluefin tuna are warm-blooded and able to regulate their body ...

Eventually, they'll go back to their own river, swimming and leaping back up to where they began life. Now, it's their turn to lay eggs that will hatch into young fish. Tuna fish live in salty water.