They can reach a maximum known size of 170 cm and a weight of 80 kg
As far as we can tell, the giant horse mackerel, Caranx ignobilis (also known as the giant king fish, trevally humble, trevally barrier, ulua, or GT) does not attack humans, which is a good thing because this feeding frenzy is a spectacle to contemplate.
The giant horse mackerel is a species of large marine fish classified in the Carangidae family. The giant horse mackerel is distributed throughout the tropical waters of the Indo-Pacific region, with a range extending from South Africa in the west to Hawaii in the east, including Japan in the north and Australia in the south. Two were documented in the eastern tropical Pacific in 2010 (one captured in Panama and another seen in Galapagos), but it remains to be seen if the species will be established there.
The giant horse mackerel is distinguished by its steep head profile, strong tail shields, and a variety of other more detailed anatomical features. It usually has a silver color with occasional dark spots, but males can be black once they mature. It is the largest fish of the genus Caranx, growing to a known maximum size of 170 cm and a weight of 80 kg.
The giant horse mackerel inhabits as a juvenile a wide range of marine environments, from estuaries, shallow bays and as an adult lagoons to the deepest reefs, offshore atolls and large inlets. It is known that the juveniles of the species live in waters of very low salinity, such as coastal lakes and upper rivers, and tend to prefer turbid waters.
It is an apex predator in most of its habitats, and is known to hunt individually and in schools. The species predominantly consumes various fish as prey, although crustaceans, cephalopods and molluscs constitute in some regions a considerable part of their diets.
The species has some quite novel hunting strategies, including following monk seals to choose prey that escape, as well as using sharks to ambush prey.
It reproduces in the warmer months, with different peaks per region. Spawning occurs at specific stages of the lunar cycle, when they congregate in large schools to spawn in reefs and bays, with reproductive behavior observed in nature. The fish grows relatively fast, reaching sexual maturity to a length of about 60 cm at three years of age.
The giant horse mackerel is an important species for commercial fishing and a recognized delicacy, with the species captured with nets and lines by professionals and bait and lures by fishermen. Catch statistics in the Asian region show hauls of 4,000 to 10,000 tons.