The rainbow runner (Elagatis bipinnulata), also known as the rainbow yellowtail, Spanish jack and Hawaiian salmon, is a common species of pelagic marine fish of the jack family, Carangidae. The species is widespread throughout the tropical and subtropical waters of the world, inhabiting both coastal and offshore areas. The species is the only member of the genus Elagatis, which was created 15 years after its initial description, and is closely related to the amberjacks. The rainbow runner is easily distinguished by its body shape, and the brilliant colouration which gives the fish its name. It is a fast-swimming predator, taking small fish, cephalopods, and a wide variety of planktonic crustaceans. The species reaches sexual maturity around 60 cm (24 in), and spawning takes place at different times, with some populations spawning year round, while others only spawn at certain times of the year. The species is a well known game fish, taken by a variety of fishing methods, and is a well-regarded table fish. Large numbers of the species are taken as bycatch in tuna- and shark-fishing operations and marketed.
The rainbow runner is the only species in the monotypic genus Elagatis, which is one of 30 genera in the jack family, the Carangidae. The Carangidae are perciform fishes in the suborder Percoidei.[3] The species was first scientifically described in 1825 by French zoologists Jean René Constant Quoy and Joseph Paul Gaimard based on the type specimen collected from the Indian Ocean, somewhere in the Malay Archipelago. They named the species Seriola bipinnulata, believing the species was related to the amberjacks.[4] This was later revised to the genus Seriolichthys by Bleeker before the species was found to warrant a new genus. The genus Micropteryx was initially created, but was already in use in the Lepidoptera.[5] In 1840, Frederick Debell Bennett created the genus Elagatis, taken from a name published in a whaling voyage memoir,[6] which he used in combination with the specific name bipinnulatus, which was deemed to be incorrect, as the genus name is feminine and the original spelling of bipinnulata was reinstated.[7] Phylogenetically, the species is most closely related to the amberjack genus, Seriola, being the most basal member identified of the carangid tribe Naucratini. This has been determined by the sequencing of the mitochondrial cytochrome b genome, as well as older morphological studies.[8]
The species' wide range has led to a wide array of local common names, with the most common English name being rainbow runner in reference to its colouring. Other names frequently applied include rainbow yellowtail,[4] Hawaiian salmon, salmon (incorrectly), Spanish jack, salmon del alto (Cuba), and over 20 other names in various languages.[2]