Tuna Thunnus thynnus Other common names: Bluefin Size, Migration and breeding: Commonly 16 to 79 inches, can grow to 118 inches and 1,500+ pounds. Western Atlantic bluefin tuna are sexually mature at approximately age 8 (80 inches Curved Fork Length). Eastern Atlantic bluefin are sexually mature at about age 5 (60 inches CFL). Atlantic bluefin tuna spawn in the Gulf of Mexico (April - June) and in the Mediterranean Sea (June -July). Range: Bluefin are widely distributed throughout the Atlantic. They are found in the western Atlantic along Labrador and Newfoundland, southward to Tobago, Trinidad, Venezuela, and the Brazilian Coast. Distribution in east Atlantic extends as far north as Norway and Iceland, and as far south as northern West Africa. Also exists in the Mediterranean Sea. Description: Bluefin have a fusiform body, compressed and stocky in front. The pectoral fin does not reach the origin of the 2nd dorsal fin. The height of the 2nd dorsal fin is greater than that of the 1st dorsal fin. The liver is striated on the ventral surface, and a swimbladder is present. There are 34-43 gill rakers on the first gill arch. The back and upper sides are dark blue to black with a gray or green iridescence. The lower sides are silvery, marked with gray spots and bands. The 2nd dorsal fin is reddish-brown, and the anal fin is dusky with some yellow. The finlets are yellow, edged with black. The caudal keel is black at the adult stage, but is semi-transparent when immature.