Albacore, Thunnus alalunga
The Albacore, Thunnus alalunga, whose common Spanish name is albacora, is a member of the Mackerel or Scombridae Family, known collectively as macarelas in Mexico. Globally, there are eight species in the genus Thunnus, six of which are found in Mexican waters, two in the Atlantic, one in the Pacific, and three in both the Atlantic and the Pacific.
The Albacore have elongated fusiform slightly compressed torpedo-shaped bodies that are designed aerodynamically for speed. They are dark blue dorsally transitioning to silver-white ventrally. They have a faint iridescent blue band along their sides. Their anal and second dorsal fins are light yellow; their anal finlets are dark; the margin of their caudal fin is white; and their first dorsal fin is deep yellow. Their body is deepest just anteriorly of the second dorsal fin. Their anal fin has 11 to 16 rays followed by 7 or 8 finlets and their caudal fin is deeply forked with two small keels separated by one large keel at the base. They have two dorsal fins, the first being larger and deeper than the second with a long base and 11 to 14 spines of which the anterior spines are high giving it a strong concave outline; the second dorsal fin has 12 to 16 rays followed by 9 finlets. Their pectoral fins are exceedingly long (a key to quick identification) approaching half the body length and reaching well past the origin of the second dorsal fin. They have 25 to 31 gill rakers on their first arch. Their body is covered with small scales.
The Albacore are a pelagic species found worldwide in tropical and subtropical waters. They are mainly found offshore from the surface to depths of 1,185 meters (3,890 feet). They reach a maximum length of 1.52 meters (5 feet 0 inches) and weight of 60 kg (133 pounds). The current IGFA world record is 40 kg (88 pounds) with this fish caught off Gran Canaria in the Canary Islands in 1977. They are a highly migratory species with juveniles of the Pacific making trans-Pacific migrations between Japan and the west coast of North America in the spring and early summer and returning in the late fall and winter. They are normally found in surface waters with temperatures between 15.6°C (60°F) to 19.4°C (67°F); larger Albacore and be found in 13.5°C (56°F) to 25.2°C (77°F) waters. They are always found in schools and can also form mixed schools with Bluefin Tuna (Thunnus maccoyii), Skipjack Tuna (Katsuwonus pelamis), and Yellowfin Tuna (Thunnus albacares), with whom they compete for food. These schools may be associated with floating objects, including sargassum weeds. They are opportunistic daytime feeders with juveniles consuming planktonic crustaceans and larger fish preying on a combination of fish, squids, and small crustaceans. They have the ability to undergo Diel vertical migrations and follow their prey to depths of 300 meters (985 feet) in the Pacific and 600 meters (1,970 feet) in the Atlantic but normally stay above the thermal incline due to their need for high levels of oxygen in the water. They remain near the surface at night. In turn they are preyed upon by billfish, dolphins, sharks, and other tunas. Reproduction is oviparous with fairly long reproduction times with sexual maturity not reached for five years in both sexes. Each female releases between 800,000 and 2.6 million eggs annually, which are released in two batches. Larger females produce more eggs than smaller females. Fertilization is external with eggs hatching in one or two days; eggs and larvae are both pelagic. They are fast growing but have a high mortality rate. Immature individuals have sex ratios of 1:1 but males dominate mature fish. They have a lifespan of up to 12 years.
In Mexican waters the Albacore are found in all waters of the Atlantic and the Pacific with the exception that they are absent from the northern half of the Sea of Cortez and south of Mazatlán along the coast of the mainland.
The Albacore is a straightforward identification due to its exceedingly long pectoral fins with one possible exception. Juvenile Bigeye Tuna, Thunnus obesus, also have long pectoral fins but those have rounded tips.
The Albacore are one of the four main tunas (Albacore, Bigeye, Skipjack, and Yellowfin) that are fished heavily commercially and that support global populations both economically and as an important food source. Commercially the Albacore are caught via pole and line, longlines, trolling, and purse seines. They are also a by-catch of the swordfish fisheries. They are an exceptional food with most sold canned. They are the only tuna sold as “white meat” which increases their price and reduces their demand. They are known to contain mercury with larger fish having higher concentrations. They are also a top recreational fish with heavily concentrated efforts made in waters off Northwest Baja during certain times of the year. They are found well offshore and require long runs; they are generally located by monitoring temperature breaks and rapidly trolled jigs and plugs and then caught on live bait such as anchovies, sardines, and herrings. They are known for their hard strikes and powerful runs. One of the complexities of determining the status of Albacore catches globally is that many other species are called “albacore” via local cultures including Blackfin Tuna, Kawakawa, Little Tunny, Swordfish, Yellowfin Tuna, and Yellowtail Amberjack. Albacore are relatively abundant, fast growing, and are very fecund but have long reproduction cycles with high mortality. From a conservation perspective they are currently classified as Near Threatened, with possible extinction in the near future. Their catch rates are heavily monitored globally. Current landing rates are on the order of 300,000 tons per annum and are continually increasing. Their global population has declined by as much as 37% (from 800,000 tons to 500,000 tons) over the last 20 years. In certain parts of the world where their populations are below maximum sustainable yield their fishery is believed to range from Moderately Exploited to Over Exploited. Annual catch quotas and a ban on the use of driftnets are currently in place.
Albacore, Thunnus alalunga. Fish caught from coastal waters off Ensenada, Baja California, April 2016. Length: 1.25 meters (4 feet 1 inch). Weight: 15 kg (33 pounds). Catch, photo, and identification courtesy of Chris Wheaton, Loreto, Baja California Sur.