When browsing the fish market counter or reading a menu at a seafood or sushi restaurant, the terms Yellowfin, Ahi, or Bigeye tuna may be used to describe different dishes. This has consumers wondering if there are differences between these fish and what they are. Yellowfin and Bigeye tuna are both subtypes of the Ahi species, so there aren't differences between the fish as much as there are distinctions that should be noted.
The Ahi name refers to two different types of tuna, Yellowfin and Bigeye. Ahi means "fire" in Hawaiian, and references the smoke that was produced from the fishing line going over the side of the boat so quickly. The Ahi species of tuna is valued for not only being a sport fish but also for their delicious flavor. In Hawaii, Ahi are most abundant in the spring and summer, though they can be fished year-round.
The dorsal, anal and finlet fins on a Yellowfin tuna are yellow, which is where it gets its name. It also has a slimmer profile than the related Bigeye tuna. Yellowfin tuna are heavily fished in Hawaii. In terms of flavor, Yellowfin tuna is known for its mild taste and firm texture, which makes it a preferred tuna for sashimi (a Japanese preparation of thinly sliced raw fish). Yellowfin can also be marinated and grilled.
Bigeye tuna, like Yellowfin, is found in tropical and subtropical ocean waters, and is popular in Hawaii for eating and sport fishing. Bigeye tuna is characterized by its plump body, larger head and unusually large eyes. Because this fish dwells in cooler waters, it has a higher fat content than Yellowfin, which is the main distinction between the two. Though Yellowfin is widely accepted for sushi and sashimi, Bigeye is prized by purists because the extra fat provides a buttery flavor and supple texture. This higher fat content also makes Bigeye good for the grill because it won't dry out as quickly.
Tuna has always been regarded as a healthy seafood because it's extremely lean, and Ahi tuna is no different. Both Yellowfin and Bigeye varieties are naturally low in saturated fat and sodium, while rich in vitamins B6 and 12 and phosphorous. They are also both good sources of Omega-3 fatty acids and magnesium. Next time you are grilling burgers or steaks, try adding in a tuna steak. Not only is tuna heart healthy, it's a delicious and extra lean source of protein.