Rainbow runner

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.

Distribution

The rainbow runner has a circumtropical distribution, inhabiting tropical and some subtropical waters worldwide. In the Western Atlantic, the species occurs from Massachusetts and Bermuda to northeastern Brazil, including the northern and southern Gulf of Mexico, the Bahamas, and the Greater and Lesser Antilles, extending east to at least the Azores.

The species is widespread throughout the Pacific Ocean, but appears to be slightly less abundant in parts of the Indian Ocean, and rare or absent in the Persian Gulf.

The species is an occasional visitor to the Mediterranean Sea, generally as a Lessepsian immigrant through the Suez Canal, but has not taken up permanent residence like other species. The species also inhabits the nearby Canary Islands, possibly entering the Mediterranean from the east, also.

The species is primarily pelagic, inhabiting the upper 164 m of the water column,

sometimes close to land over rock and coral reef systems, as well as far offshore. The species occasionally comes quite close to shore, known to inhabits lagoons for short periods, and juveniles have even been reported in a Taiwanese estuary system. Rainbow runners, like other carangids such as yellowtail kingfish, are easily attracted to special fish-attracting devices (FADs), floating buoy-type structures. The species has been shown to occupy a water zone outside of the FADs up to 12 m deep and 10 m wide, treating them as if they were stationary objects.

Behaviour

Rainbow runners are fast-swimming carnivores that take a wide range of prey, including a wide variety of small fishes, cephalopods, and pelagic or planktonic crustaceans, including, shrimp and crabs. The species shows selectivity of its prey, with fish in the Pacific Ocean taking higher numbers of Decapterus macarellus, a small fish, than any other prey available. Rainbow runners may increase their swimming and prey-searching abilities rapidly with their growth, becoming more efficient at finding their preferred prey items. Rainbow runners are also one of a number of pelagic fishes that prey on open-ocean species of sea-skaters (Halobates spp.), a type of insects which rest on the surface of the ocean.

Rainbow runner themselves are important prey items for a number of larger species, with positively identified predators being Fraser's dolphin (Lagenodelphis hosei), and a number of seabirds of the family Laridae.