Giant Trevally: Bludger, Brassy Trevally, GT, Lowly Trevally, Turrum or Ulua

Giant Trevally: Bludger, Brassy Trevally, GT, Lowly Trevally, Turrum or Ulua

Giant Trevally is widely distributed throughout the tropical and subtropical waters. Namely; the Indian and Pacific Oceans, ranging along the coasts of three continents and many hundreds of smaller islands and archipelagos.

Scientific name: Caranx Ignobilis

Giant Trevally Alternate Common Names;

Bludger, Brassy Trevally, GT, Lowly Trevally, Turrum or Ulua.

Family Classification: Carangidae

Despite the similarity in their names, Trevally – Carangidae is 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.

Identification Characteristics:

There are at least 23 species of trevally found along the east coast of Australia. Also actively swimming; extremely strong and powerful fish and highly streamlined species due to its very fine scales.

Most of the species are silver in colour with some species having a blue or gold colouration. Also their body and head have silvery grey with a black back and a paler belly.

Mature males usually are darker than females, sometimes head and fins are completely black. Also, their fins are usually uniformly grey to black. In addition to their leading edge and tips of lobes on dorsal and anal fins paler. Juveniles and young adults body are 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 another trevally? Adults are very large, they have no scales on the underside, typically a patch of pre-pelvic scales. Also, the head has a steeply convex profile.

The most prominent features of the Giant Trevally are; The forked caudal or tail fin and the ridge of plates on each side of the base of the tail.


Giant Trevally is the most powerful apex predator in its habitats. Also known to hunt individually and in schools.

During the summer months found in southern waters of Australia’s east and the west coast. Also other all marine habitats, near rock edges of coral and rocky reefs. Also submerged Bomboras, tidal flats and channels. And near the narrow tidal formations between tropical waters. Often over large expanses of deeper sand banks and mud bottoms between the reefs.

Older individuals tend to move to deeper seaward reefs, Bomboras and drop off’s 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. Same estuaries where juveniles may also habitat.

In Hawaii protected inshore waters the juveniles and young adults are the largest in the Carangidae species.  With all the other species apparently preferring the outer, less protected reefs.

Giant Trevally relatively fast-growing. They can reach large sizes between 55 to 80kg and even heavier, with lengths up to 170cm. When they reach maturity five years of age reach approximately 95cm.

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 consumes 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 and Whitebait.


Poppers or Surface Lures.


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