Giant Trevally are widely distributed throughout the tropical and subtropical waters of the Indian and Pacific Oceans, ranging along the coasts of three continents and many hundreds of smaller islands and archipelagos.
Scientific Name: Caranx Ignobilis.
Alternate Common Names:
Bludger, Brassy Trevally. GT, Lowly Trevally, Turrum, Ulua.
Family Classification: Carangidae.
Despite the similarity in their names, Trevallys – Carangidae are unrelated to Trevallas – Centrolophidae. Giant Trevally is classified within the genus Caranx, one of a number of groups known as the Jacks or Trevallies.
Caranx itself is part of the larger jack and horse mackerel family Carangidae, a group of percoid any of numerous spiny-finned fishes of the order Perciformes.
Many commercially harvested fish species are contained in this suborder, including the snappers, whitings, groupers, basses, perches, and porgies.
There are at least 23 species of trevally are found along the east coast of Australia, extremely strong and powerful fish actively swimming, highly streamlined species with very fine scales.
Most species are silver in colour with some species having a blue or gold colouration, their body and head silvery grey with black back, usually paler belly, mature males usually darker than females, sometimes head and fins completely black, fins are usually uniformly grey to black, their leading edge and tips of lobes on dorsal and anal fins paler. Juveniles and young adults body is generally more silvery and fins are also paler.
Fish from turbid coastal waters often have yellow fins and anal fin usually the brightest.
How to distinguish from other trevally, adults very large, they have no scales on the underside, typically a patch of pre-pelvic scales, head has steeply convex profile.
The most prominent features in Giant Trevally are the forked caudal or tail fin and the ridge of plates on each side of the base of the tail.
The Giant Trevally is a powerful apex predator in most of its habitats, and is known to hunt individually and in schools.
During summer months the Giant Trevally can be found in more southern waters of Australia’s east and west coasts, they are found in all marine habitats, near rock edges of coral and rocky reefs, submerged bomboras, tidal flats and channels and the narrow tidal formations between tropical waters, often over large expanses of deeper sand and mud bottoms between the reefs.
Older individuals tend to move to deeper seaward reefs, bomboras and drop offs away from the protection of fringing reefs, often to depths greater than 80m, also known to tolerate the low salinity waters of estuaries and rivers, with juveniles may occur in estuaries.
In Hawaii, the juvenile to young adult are the most common large carangid in the protected inshore waters, with all other species apparently preferring the outer, less protected reefs.
Giant Trevally relatively fast-growing and can reach larges sizes between 55 to 80kg even heavier with lengths up to 170cm, at approximately 95cm and five years of age when they reach maturity.
Spawning adults can form massive congregations, however other than these spawning periods larger adults are often solitary to an area of reef .
The species predominantly takes various fish as prey, although crustaceans, cephalopods and molluscs make up a considerable part of their diets in some regions.
Fish flesh, Garfish, Hardyheads, Pilchard, Prawn, Squid, Whitebait.
Poppers, Surface Lures.