Description: The body of the bluefin tuna is cigar-shaped and robust. The head is conical and the mouth rather large. The color is dark blue above and gray below. Bluefin tuna can easily be distinguished from other members of the tuna family by the relatively short length of their pectoral fins. Their livers have a unique and definitive characteristic in that they are covered with blood vessels (striated). In other tunas with short pectoral fins, such vessels are either not present or present in small numbers along the edges.