Golden trevally

Species of fish

The golden trevally (Gnathanodon speciosus), also known as the golden kingfish, banded trevally or king trevally, is a species of large marine fish classified in the jack and horse mackerel family Carangidae, and the only member of the monospecific genus Gnathanodon. The golden trevally is widely distributed throughout the tropical and subtropical waters of the Indian and Pacific Oceans, ranging from South Africa in the west to Central America in the east, extending to Japan in the north and Australia in the south. The species predominantly occupies inshore waters where it inhabits both reef and sandy substrates. The golden trevally is easily distinguished from its relatives by its fleshy, rubbery lips and unique colouration, which ranges from bright yellow with black bars as a juvenile to a golden silvery colour as an adult. It is known to grow to in length and in weight. The golden trevally schools as a juvenile, often closely following larger objects including sharks and jellyfish. The species uses its protractile jaws to suck out prey from the sand or reef, and consumes a variety of fish, crustaceans and molluscs. Spawning aggregations gather at night at different times of the year throughout its range. The golden trevally is a considerable constituent of several Middle Eastern fisheries and being of minor importance to many others, with a worldwide annual catch of to recorded between 2000 and 2010. The golden trevally is a popular gamefish, taken by bait, lure, fly and also spear throughout its range. Several Asian countries currently farm the fish in caged aquaculture. Due to their brilliant colouration, juveniles are popular in marine aquaria.

The golden trevally is the only member of the monotypic genus Gnathanodon, which is one of the thirty genera in the jack and horse mackerel family Carangidae, which in turn is part of the order Carangiformes. The species was scientifically described for the first time by the Swedish naturalist Peter Forsskål in 1775. Forsskål referred the species to the genus Scomber, where many jacks were placed before the recognition of the family Carangidae. The species is initially referred with two epithets; Scomber rim, speciosus in this publication; however the following page names it as Scomber speciosus with 'rim' given as a transcription of the species' Arabic name. Consequently, authorities regard Scomber rim as a junior synonym. Forsskål's description was based on an individual from the Red Sea off Jeddah, Saudi Arabia. The holotype has since been lost and a neotype was invalidly designated by Ronald Fricke in 1999. The specific epithet speciosus is Latin for beautiful. The species was transferred to Caranx before the Dutch ichthyologist Pieter Bleeker placed it in its own genus Gnathanodon, with this name derived from the Latin for 'toothless jaws'. A study on the phylogenetic relationships of the Carangidae based primarily on osteology by Soko Gushiken found that Gnathanodon is closely related to and forms a monophyletic group with Caranx. The species has yet to be included in any molecular phylogeny study of the family.

The golden trevally is widely distributed throughout the tropical and subtropical waters of the Indian and Pacific Oceans. Golden trevally are recorded from many Indian Ocean islands including Madagascar, Seychelles and The Maldives. Golden trevally appear to prefer clear water to turbid waters, One known exception to this was the capture of several individuals in a shallow mangrove swamp in Baja California which appeared to be foraging for prey.

The golden trevally is a relatively large fish, growing to a maximum recorded size of 120 cm (47 in) in length and 15.0 kg in weight. It is similar to most other trevallies and jacks in having a compressed, oblong body, with the dorsal profile slightly more convex than the ventral profile, particularly anteriorly. The species' mouth is one of its defining features; the mouth is highly protractile and fleshy, with specimens greater than 90 mm having no teeth on the jaws, vomer or tongue. Smaller individuals have a series of small villiform teeth in both jaws. The dorsal fin is in two parts, the first with 7 spines, the second with 1 spine and 18 to 20 soft rays. The anal fin has 2 detached spines followed by 1 spine and 15 to 17 soft rays,