Thunnus albacares
Yellowfin tuna, also known as “Ahi” lives in pretty much the same waters as yesterday’s Mahi-mahi. Another favorite of sport fisherman, this beautiful fish can grow to lengths of eight feet and weigh over 400 pounds. The dorsal and anal fins are bright yellow, thus the name, and the body is a dark, almost metallic blue with a silver belly.
Yellowfins like to school with other fish of their size, like porpoises, other tuna species, whales and whale sharks. They have a similar diet to the Mahi-mahi, enjoying other fish, crustaceans and squid.
Yellowfin is sold frozen, dried or canned, but it has become very popular as sashimi and as main course protein at home and on menus. Often treated like a premium meat, the fish is seared to rare or medium rare. Yellowfin tuna has flesh coloration that varies from pink in smaller fish to deeper red in larger fish. Larger fish typically have a higher fat content than smaller fish, and this is a desirable attribute for raw fish products, as well as for broiling.
Fresh yellowfin undergoes oxidation of pigmented protein when it is exposed to air. The exposed flesh changes from a beautiful red to a less desirable brown color in just a matter of days. For this reason, yellowfin should not be filleted until shortly before use. Yellowfin from Hawaii is most plentiful during the summer months.