Tuna ID required!

A slightly fatter than usual longtail tuna methinks Andrew
the dots & dashes below the lateral line are not an unusual coloration variation in a number of species & do not provide a diagnostic coloration , rather they confuse the angler about the ID as they are not highly visible on every capture & attract attention when you do see them for the first time.
the dots & dashes are triggered by the state of excitement of the tuna.

For our US friends......................................... this species is not a true bluefin ( Atlantic,Pacific, or Southern) , Its found in the Indian Ocean & Western Pacific . Its a coastal species rather than oceanic like the true bluefins.
It makes lousy sashimi ( fibrous flesh )..............even makes a tough canned product ( but that doesn't stop some from labling it by its old name 'northern" bluefin.