How to Identify Giant Trevally

To identify Giant Trevally (Caranx ignobilis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults typically range from silvery-grey to dark grey or black dorsally, fading to a lighter silvery-white ventrally. Larger males, especially during spawning or aggressive displays, can become almost entirely black. Juveniles are silvery with 5-6 dark vertical bands on their flanks, which fade with age. The fins are generally dusky to black.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Steeply sloped head profile, particularly in larger individuals., Large, powerful, and deeply forked caudal fin., Prominent, keeled scutes (bony plates) along the posterior portion of the lateral line, numbering 26-38., Large, terminal mouth with strong jaws and numerous small, conical teeth., Absence of a dark spot on the operculum (gill cover), which distinguishes it from some other Caranx species.

Dorsal fin

Two dorsal fins; the first with 8 spines, the second with 1 spine and 18-21 soft rays. The anterior rays of the second dorsal fin are elongated.

Tail fin

Deeply forked, powerful caudal fin.

Pectoral fin

Long, falcate (sickle-shaped) pectoral fins, longer than the head.

Distinctive fins

Anal fin with 2 detached spines followed by 1 spine and 15-17 soft rays. Pelvic fins are relatively small.

Identification Tips

1. 1

   Size and Body Shape

   Look for a very large, robust, and compressed body. Adults can reach up to 170 cm (67 inches) in length and weigh over 80 kg (176 lbs).

2. 2

   Coloration

   Adults are typically dark grey to black dorsally, fading to silvery-white below. Large males can be almost entirely black. Juveniles have distinct vertical bands.

3. 3

   Head Profile

   Observe the steeply sloped head profile, especially in larger individuals, which gives it a blunt appearance.

4. 4

   Lateral Line Scutes

   Count the scutes (bony plates) on the posterior part of the lateral line; Caranx ignobilis typically has 26-38 strong scutes, which are very prominent.

5. 5

   Opercular Spot

   Note the absence of a dark spot on the operculum, a key differentiator from some other trevally species.

6. 6

   Fin Shape

   The long, falcate pectoral fins and deeply forked caudal fin are characteristic.

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