Little Tunny, Euthynnus alletteratus
Little Tunny, Euthynnus alletteratus. Fish caught from coastal waters off Ft. Lauderdale, Florida, May 2021. Length: 70 cm (2 feet 4 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Little Tunny, Euthynnus alletteratus. Fish caught from coastal waters off Sebastian, Florida, May 2021. Length: 71 cm (2 feet 4 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.
Little Tunny, Euthynnus alletteratus. Fish caught from coastal waters off Manasquan, New Jersey, September 2014. Length: 71 cm (2 feet 4 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
The Little Tunny, Euthynnus alletteratus, is one of the smaller members of the Mackerel or Scombridae Family, also known as Bonito and the False Albacore and in Mexico as bacoreta. Globally, there are three species in the genus Euthynnus, and all three are found in Mexican waters, one in the Atlantic and two in the Pacific Ocean.
The Little Tunny has an elongated fusiform small-sized tuna-like body. They are metallic blue or blue-green dorsally and transition to silver ventrally. They have dark wavy “worm-like” markings on the upper back that extend backwards from the middle of the dorsal fin. They have 3 to 7 dark spots on their lower sides between their pelvic and pectoral fins, a key to rapid identification. Their head has a short snout, and a large mouth, with conical teeth set into slender jaws. Their anal fin has 11 to 15 rays and 7 to 10 finlets; their caudal fin is large and crescent-shaped with 2 small keels separated by 1 large keel at the base with a very slender peduncle; their first dorsal fin has 9 to 16 steeply descending spines giving a strongly concave appearance; their second dorsal fin has 11 to 13 rays, is set very close to the first, is much smaller than the first, and has 7 to 10 finlets; their pectoral fins have 26 or 27 spines and are short and broad; and, their pelvic fins are short and broad. They have 19 to 45 gill rakers on the first arch. They do not have scales, except along the lateral line on the corselet where a thick band is found encircling the body.
The Little Tunny is a migratory pelagic species found from the surface to depths up to 150 m (492 feet), usually in large schools of mixed species, including the Atlantic Bonito, of similar size. The juveniles form larger schools near shore; the adults are found in smaller, loosely packed groups in the open ocean. They frequent coastal areas with swift currents, near shoals and offshore islands. They prefer waters that are between 24oC (75oF) and 30oC (86oF). They are known to make seasonal migrations, moving southward in the winter and northward in the spring. They reach a maximum of 1.22 m (4 feet 0 inches) in length and 16.5 kg (36 lbs 5 oz) in weight. As of March 31, 2023, the International Game Fish Association world record for length stood at 91 cm (3 feet 0 inches) with the fish caught from coastal waters off Spain in September 2016. As of March 31, 2023, the International Game Fish Association world record for weight stood at 16.78 kg (36 lbs 16 oz) with the fish caught from coastal waters off Spain in June 2020. The Little Tunny is an opportunistic nocturnal predator that primarily feed on schooling pelagic small fish and schooling invertebrates and smaller amounts of cephalopods, crustaceans, and gastropods. In turn they are preyed upon by dorado, marlins, rays, sailfish, sharks, swordfish, wahoo, and sea birds. They are exceedingly fast swimmers, capable of reaching speeds of 64 km/hr (40 mph). Reproduction involves batch spawning with each female spawning several times releasing up to 1,750,000 annually. Their eggs and larvae are pelagic and take on an adult appearance very quickly. They have live spans of ten years. The Little Tunny is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Little Tunny can be confused with the Atlantic Bonito, Sarda sarda, the Bullet Mackerel, Auxis rochei, the Frigate Mackerel, Auxis thazard, and the Skipjack Tuna, Katsuwonus pelamis, from the Atlantic (all of which lack the black spotting between the pectoral and pelvic fins) and its close relatives from the Pacific Ocean, the Black Skipjack, Euthynnus lineatus and the Kawakawa, Euthynnus affinis.
The Little Tunny is the most common tuna in the Atlantic Ocean with a wide range in all warm temperate and tropical waters. In Mexican waters they are only found along the east coast of the Yucatán Peninsula in the Caribbean; they are absent from the Gulf of Mexico.
From a conservation perspective, the Little Tunny is currently considered to be of Least Concern, with stable widely distributed populations. A limited number of regulations have recently been put in place in some parts of their range. However, catch levels of small tunas (estimated to be on the order of 100,000 tons per year) are poorly documented as most catches of small tunas are made by artisanal fishermen utilizing gill nets and go unreported. They are caught as a by-catch by purse seiners, mid-water trawlers, troll line, drift nets and gill nets and often discarded. They are also targeted by recreational fishermen, famous for their speed and stamina, that can also be caught off the beach. They are also utilized as a live bait, targeting marlin, sailfish and sharks. Their meat is coarse in texture, strong in flavor, and dark in color and they are not favored by some but they are sold fresh, frozen or canned for human consumption. They are known to have a short shelf life and there are reports that they contain ciguatera toxin. They are utilized extensively by the pet food industry.