The albacore (Thunnus alalunga), known also as the longfin tuna, is a species of tuna of the order Perciformes. It is found in temperate and tropical waters across the globe in the epipelagic and mesopelagic zones. There are six distinct stocks known globally in the Atlantic, Pacific, and Indian oceans, as well as the Mediterranean Sea. The albacore has an elongate, fusiform body with a conical snout, large eyes, and remarkably long pectoral fins. Its body is a deep blue dorsally and shades of silvery white ventrally. Individuals can reach up to 1.4 m (4.6 ft) in length.
Albacore are pelagic predators that eat a variety of foods, including fish, crustaceans, and cephalopods. They are unique among tuna in that their primary food source is cephalopods, with fish making up a much smaller portion of their diet. Reproduction usually occurs from November to February and is oviparous. An adult female can release over 2 million eggs in a single cycle. Fry generally stay near where they were spawned for about a year before moving on. Albacore form schools based on their stage in the life cycle, but also combine with other tuna like the skipjack tuna, yellowfin tuna, and bluefin tuna. Once grown, schools are highly migratory.
The albacore is a very economically important fish and is a target of commercial and recreational fisheries. It was originally the basis for the United States tuna-canning industry and is no less important today, making up significant percentages of the gross domestic products of various Pacific nations. It is listed as Near Threatened by the International Union for the Conservation of Nature (IUCN) because of the threat of overfishing. Several stocks are in significant decline and the species' overall population trend is decreasing.
The albacore has an streamlined, fusiform body with a conical snout, large mouth, and big eyes. Its body is dark blue dorsally, shades of silvery white ventrally, and covered by small scales. The pectoral fins begin slightly before the first dorsal fin and extend well beyond the front of the anal fin, usually as far as the second dorsal finlet, often as long as 30% of the fish's total length. Like the fish's body, the fins are dark blue on top, but change to a medium yellow color on the underside. They are markedly shorter in fish under 0.5 m (1.6 ft) in length, often resulting in confusion with T. obesus juveniles, which also have long pectoral fins, though these are rounded at the tips where the albacore's taper to a point. The first dorsal fin is a deep yellow and the second, which is smaller than the first, is a light yellow, as is the anal fin. It has 7-9 dorsal finlets and 7-8 anal finlets, dark blue and silvery white in color respectively, matching the part of the fish's body they are on. The caudal fin is also silvery white. At 1.4 m (4.6 ft) maximum length, the albacore is the smallest of the bluefin tuna. It reaches sexual maturity at 0.9 m (3.0 ft) and its common length is only slightly larger at 1.0 m (3.3 ft). Males and females exhibit no sexual dimorphism.[