Little tunny, Euthynnus alletteratus
The little tunny is found widespread in temperate and tropical waters of the Atlantic Ocean, Black Sea and Mediterranean Sea. It is the most common tuna and is highly migratory, with a range from Cape Cod, Massachusetts to Brazil in the Western Atlantic. In the Eastern Atlantic it is found from Skagerrak to South Africa. The little tunny will form schools close to the shoreline, around inlets, and sandbars that can cover up to two miles. This fish prefers warm water and will migrate south in the fall and winter. And migrate north in the spring and summer.
The little tunny has a small stream-lined body built for speed and endurance. The mouth is fairly large with a protruding lower jaw that contains cone shaped teeth that curve inward. The front dorsal fin has 10 to 15 spines that descend in height and the second dorsal fin is followed by eight smaller fins. The anal fin has 11 to 15 rays with 7 smaller fins trailing toward the tail. The only scales on the little tunny are a band along a lateral line the length of the body and on another band circling the body.
The typical color of the little tunny is a metallic blue or bluish-green with dark wavy stripes extending forward from the tail to the middle of the first dorsal fin. The belly is white with several dark spots around the pectoral and pelvic fins. These spots distinguish the little tunny from other tuna of the same size like the skipjack, frigate, Atlantic bonito, and bullet tunas.
The little tunny can reach a weight of 26 pounds but the average being 15. The average length of this species is 33 inches but can reach 40 inches or more. The largest little tunny on record was 48 inches and weighed 36.5 pounds.
The little tunny lacks a swim bladder so it must constantly keep moving to keep the fish afloat; the pectoral fins are used to maintain the fish’s position in the water. The stomach sac of the little tunny stretches almost the length of its body.
The little tunny is a nocturnal feeder with a diet that consists mainly of small fish that swim in schools. However, it will also consume crustaceans, cephalopods, gastropods, sardines, and squid. Seasonal changes and food availability determines what food the little tunny will eat.
The little tunny will spawn in water temperatures of 77 degrees or more during the months of April through November in the Atlantic. In the Mediterranean the spawning occurs between May and September. The little tunny will spawn in waters 100 to 130 feet deep and during the mating season the female can lay almost 2 million eggs. The male will fertilize the eggs after being released from the female. The eggs are spherical and transparent with an amber tint.
The larvae will hatch 24 hours after fertilization and are approximately a tenth of an inch long. Eye pigmentation is visible 48 hours after hatching and teeth and fins begin to develop when the fish reach about a half inch. When the larva reaches about 4 inches long it will begin to take on the adult form. Sexual maturity begins when the fish reaches three years of age and about 15 inches in length.
The little tunny is a predatory fish but it is also preyed upon by marlins, sharks, rays, and other larger tuna. Sea birds and whale sharks will prey upon the larvae and small little tunny.
The little tunny is not considered a food fish because of its coarse texture, strong flavor, and dark color. However, it can be eaten, but should be bled first, baked then remove the dark stripes to reduce the fishy taste. It is also used for bait to catch other larger species of fish. There is no regulation on the capture of this fish, no size limit, no bag limit, and no closed season.
Image Caption: Drawing of the Little tunny by former FishBase staff member Robbie N. Cada. Credit: Robbie N. Cada/Wikipedia