bluefin tuna, any of a number of types of tuna characterised by their blue fins.
A member of a species of tuna, Thunnus genus, having blue fins, including
Thunnus orientalis, Pacific bluefin tuna, found widely in the northern Pacific Ocean and locally in the south.
Thunnus tonggol, longtail tuna, found in tropical Indo-West Pacific waters.
Thunnus thynnus, Atlantic bluefin tuna, found in both the western and eastern Atlantic Ocean, and also
in the Mediterranean Sea.
Thunnus maccoyii, southern bluefin tuna.