Names in different languages:
Netherlands: Geelvintonijn, Spain: Rabil, Italy: Tunnu monicu, Denmark: Gulfinnet tun, Germany: Gelbflossen-Thun, Portugal: Atum Rabil, France: Thon à nageoires jaunes, Japan: Kidaha, Indonesia: Gantarangang, Papua New Guinea: Tetena keketina, China: 黄奇串, Philippines: Badla-an.
Habitat:
The Yellowfin tuna is an epipelagic, oceanic fish, able to live above and below the thermocline, at temperatures of 18 to 31°C. Most of them can generally be found in the upper 100 m of the water column.
Distinctive Features:
The Yellowfin is the second largest tuna species. Its body is strongly fusiform shaped, and is deepest under its first dorsal fin and tapering considerably towards the caudal peduncle. There are two dorsal fins present. In mature fishes the second dorsal fin and the anal fin (directly below the second dorsal) are very long, and they will become relatively longer in larger individuals. The pectoral fin is also quite long compared to other species, reaching beyond the space between the dorsal fins. The caudal peduncle is very slender and consists of three sets of keels. There are seven to ten dorsal and ventral finlets present. A band of large scales form a circle around the body behind the head, and scales are lacking behind the corselet. The Yellowfin tuna have small eyes and conical teeth. A swim bladder is present in this tuna species.
Coloration:
Their bodies have a metallic dark blue or greenish color in the upper part, while the belly and lower sides are silvery white and they are crossed by many vertical interrupted lines. Perhaps the most distinctive is a golden stripe that runs along the sides. The second dorsal, anal fins and finlets have bright yellow color, and the finlets are bordered by a narrow band of black.
Size, Age, and Growth:
Yellowfin tuna grow fairly fast, up to 175 kgs, and have a somewhat short life span of about 7 years. Yellowfin tuna feed near the top of the food chain on fish, squid, and crustaceans. They are also prey for top predators such as sharks and large fish.
Reproduction:
The size of Yellowfin tuna at maturity varies by region, and could also vary between individuals found near- and offshore. Yellowfin reach the status of mature by the time they reach a length of 105 cm in fork length or about 25 kgs at an age of about 2 to 3 years; however there are some exceptions where fish become mature at the size of 50 to 60 cm in fork length at an age of about 12 to 15 months. The sex ratio is approximately 1:1 in juvenile fishes and adults up to 140 cm.
The reproduction of Yellowfin tuna occurs all year-round, but is most frequent during the summer months in each hemisphere. In the tropical waters of Mexico and Central America, it has been determined that Yellowfin spawn at least twice a year. It is believed that 26°C is the minimum temperature for spawning and each female spawns several million eggs per year.
Among the tuna species, the larval of Yellowfin tuna can be identified by a lack of pigment on the tail and by the presence of a single spot of black pigment under the chin.
The Yellowfin juveniles grow quickly, weighing approximately 3.4 kg at 18 months and 63.5 kg at 4 years.
Stock Status of Yellowfin Tuna
Conservation:
The Yellowfin tuna got listed 2011 on the International Union for the Consercation of Nature and Natural Resources (IUCN) “red list” under the category Near Threatened.
For comments and to add additional information, please email to: support@atuna.com